Environmental Impact Assessment of Aerial Spraying Btk in NZ for painted apple moth

February 2003

Contents

• Summary

1. Introduction
2. Proposed Method Of Eradication
3. The Environmental Impacts Of Spraying Btk
4. Preventing Or Reducing Any Adverse Effects
5. Comparison Between The Proposed Means Of Eradication And Alternative Options For Responding To Painted Apple Moth
6. Consultation
7. References

• Glossary
• Appendix 1

Summary

Painted apple moth (Teia anartoides) is a potentially significant pest of New Zealand's natural and planted forests, horticultural crops, amenity trees and gardens. MAF is planning an eradication programme for painted apple moth using the biological insecticide based on Bacillus thuringiensis kurstaki (Btk). Btk would be applied in an aerial and ground-based spraying programme. This environmental impact assessment (EIA) evaluates the potential environmental impacts of the proposed spray programme. The EIA has been written so that it may apply in any part of New Zealand to which painted apple moth may spread in the future. An evaluation of whether an assessment on impacts of Btk to native flora and fauna is required for significant natural areas should be determined on a case by case basis in the event of painted apple moth establishment outside the Auckland region.

Btk is most effective against the early instar larvae of moths and butterflies. Spraying with Btk is therefore not likely to have any long-term adverse effect on New Zealand's soils, waters, plants, food sources or native animals, birds and fish. Non-target moth and butterfly species will undoubtedly be affected in areas where the insecticide is applied. However, numbers of moths and butterflies should be restored within three years of a spray programme, provided that the species are able to migrate back into the sprayed area. If a target area contains moth or butterfly species, which are rare or endangered and have restricted distributions, spraying with Btk may have an adverse effect on these species. There are a number of rare species reported from the general area of infestation of painted apple moth, which will need to be considered during any spray programme¹. Other non-target invertebrate species will not be affected by Btk.

The spray programme could affect birds, which are dependent upon caterpillars as their food within the spray zone. The spray zone is currently limited to a small area of Auckland and such effects would be found where any bird was restricted in feeding to within the spray zone.

The spray programme may affect businesses involving the rearing of butterflies or moths², and may also cause traffic disruptions. In addition, a level of public concern inevitably accompanies spray programmes. Apart from these potential effects, no other economic, social or cultural impacts have been identified.

The main means for reducing the potential adverse effects of the spray programme are compliance with various relevant Acts, regulations, policies and plans; a public communications strategy; a contingency plan for emergencies; safe storage, transportation and disposal of Btk; safeguards for workers, sensitive individuals and sensitive receiving environments; and monitoring the environmental effects of the programme.

Alternative responses to painted apple moth include:

• doing nothing (this may result in painted apple moth spreading throughout New Zealand);
• using an insecticide such as Decis, Dimilin or Spinosad (not favoured because of adverse effects on non-target organisms or lack of information);
• using biocontrol to reduce painted apple moth populations (no biocontrol agents have been tested at this stage, and these techniques are unlikely to eradicate painted apple moth); or
• using other population control measures (techniques such as trapping and mating disruption, which are reliant on synthetic attraction pheromones- these have not yet been developed for painted apple moth).

1. Introduction

1.1 Why is this Environmental Impact Assessment being prepared?

An exotic insect, the painted apple moth (scientific name Teia anartoides) was found in Auckland suburb of Glendene on 5 May 1999. Painted apple moth is known to be polyphagous, and has a wide known host range including over 60 plant species. It is considered that painted apple moth could become a significant pest of New Zealand's natural and planted forests, horticultural crops, amenity trees, and gardens, if it spreads throughout the country.

There are several methods available for eradicating or controlling the painted apple moth. Eradication programmes aim to completely eliminate a pest species, whereas control programmes aim to reduce the pest population to a level at which the amount of damage the pest causes is acceptable³. The New Zealand government decided on an eradication campaign, based on the use of a biological insecticide Foray 48B, containing the bacterium, Bacillus thuringiensis kurstaki (Btk) as the active ingredient (Anon. 2001b).

The main purposes of this Environmental Impact Assessment (EIA) are:

• to evaluate the potential environmental effects of the programme;
• to consider how any adverse effects might be prevented or reduced; and
• to compare the programme with alternative methods (including controlling the moth, rather than eradicating it, and doing nothing).

This document is not an operational document and therefore does not contain details of sites to be treated, methods of application, contingency planning or monitoring programmes. A Health Risk Assessment (Auckland District Health Board 2002) for the painted apple moth programme has been completed, the impacts of the programme on human health are reviewed in it.

The content of this EIA represents the MAF's current thinking and is not official Government policy.

1.2 Painted apple moth

In May 1999, the Ministry of Agriculture and Forestry (MAF) reported the discovery of a type of moth related to the white-spotted tussock moth on three properties in an industrial area in the western Auckland suburb of Glendene. This was the first find of the painted apple moth, Teia anartoides (Lepidoptera: Lymantriidae), in Auckland⁴. The painted apple moth is a native of parts of Australia (in South Queensland through to Victoria and the ACT, the south east of South Australia, and Tasmania) where it is an occasional pest of a wide variety of plants, including apple and stonefruit trees and various ornamentals (cypress pine, roses, gladioli and geraniums). Painted apple moth has sometimes caused more serious problems on pines and acacias. The caterpillars damage foliage during spring, summer and autumn. They also feed on skins of developing fruit in Australia. There are several generations of painted apple moth each year. In its native Australia the painted apple moth prefers acacia and wattle trees but has been found feeding on and damaging a wide range of host plants, including pines and fruit trees. In New Zealand, it has been found feeding on a number of additional hosts including many common native and introduced plants.

1.3 What is the response to painted apple moth in New Zealand?

The government has approved an eradication programme for the moth including an aerial and land-based spraying programme using an insecticide based on Bacillus thuringiensis kurstaki (commonly known as Btk), Foray 48B. Foray 48B is a biological insecticide - that is, it contains a strain of a naturally occurring bacterium (Bacillus thuringiensis).

2. Proposed method of eradication

2.1 What is Btk?

2.1.1 Bacillus thuringiensis

The bacterium Bacillus thuringiensis (Bt) is a rod-shaped bacterium which occurs naturally throughout the environment (soil, foliage, water and air) in most countries of the world, including New Zealand⁵. Currently there are 82 known "serovars" which have the status of subspecies and over 40,000 isolates are thought to be held in collections around the world (Glare and O'Callaghan 2000).

Like many bacteria, Bt has a two-phase life cycle composed of a vegetative cell stage, which occurs when environmental conditions are favourable and the cells are young, and a spore-forming stage (known as sporulation), which occurs during adverse environmental conditions or when cells approach old age. The spores are termed endospores once they are released from the vegetative cells. A special characteristic of Bt is that at the stage when spores form, the vegetative cells of the bacterium produce substances known as protein crystals. These crystals are released into the environment, along with the endospores, when the vegetative cell degrades. The protein crystals produced by various strains of Bt contain toxins which have varying toxic properties, depending on the strain of Bt involved. Over 170 distinct endotoxins have been identified from various Bt isolates.

2.1.2 Commercial development of Bt

In the 1930s, French scientists developed a Bt formulation that could be used to control caterpillar populations. Scientists of the United States Department of Agriculture (USDA) further developed the Bt formulation in the 1960s so that it could be mass produced economically. Research is continuing in several countries on the many Bt strains to test their effectiveness against caterpillars and other insects. Over 100 commercially available products have been based on Bt and Bt-based biopesticides make up over 90% of all biopesticide sales world-wide. The most important commercial subspecies are israelensis (Bti), which controls aquatic mosquito and sandfly larvae, and kurstaki (Btk), which is active against Lepidoptera (caterpillars).

Bt formulations are used in New Zealand in both conventional and organic agriculture. In terms of organic certification Bt is a permitted pest management material under Bio-Gro and Certenz standards. However Foray 48B, as a product, is not a certified organic product. Some Btk-based formulations have been organically approved, including Dipel, which is organically certified and available for use. Unfortunately, Dipel is not suitable for aerial application.

Foray 48B based on Btk was used in the 1996-7 Operation Ever Green eradication programme for white-spotted tussock moth in Auckland.

2.1.3 Bacillus thuringiensis kurstaki (Btk)

Btk is widely used to control moth and butterfly (Lepidoptera) pests as it specifically affects the larvae (caterpillars) of some of these species. Btk formulations are produced commercially by a number of companies in the US and Europe. Large quantities of Btk have been used over the past 30 years in North America, especially to control gypsy moth populations.

Natural epizootics (widespread insect disease) caused by Btk have been observed only very rarely in the natural environment, and usually when caterpillars are in a confined environment (USDA 1995; Glare and O'Callaghan, 2000).

2.1.4 How does Btk work?

The protein crystal produced by Btk includes a substance known as a delta-endotoxin which is toxic to members of the Order Lepidoptera (moths and butterflies). Endospores of Btk are also toxic to the caterpillars of many moths and butterflies. The spores and endotoxins in the protein crystal are known as the "active ingredients" in Btk formulations, because it is these ingredients which kill the insects. However, the protein crystal is not toxic until it is swallowed by a caterpillar - it must be present on a leaf and eaten by a caterpillar before it takes effect.

Once the crystal is eaten by the caterpillar it is activated by the specific conditions found in the caterpillar gut (namely, alkaline conditions and the presence of certain digestive enzymes). The toxin works by attacking the gut lining. This causes paralysis of the gut and the caterpillar stops feeding as little as two minutes after eating the Btk. The caterpillar will die of starvation two to five days later, depending on environmental conditions. Vegetative growth of Btk within the caterpillar and septicaemia caused by Btk may also help to kill the caterpillar.

Susceptibility to Btk depends on (BC MOH 1992):

• the pH of the gut (a pH of 9.0-10.5 is ideal);
• the presence of specific digestive enzymes which dissolve the crystals (these enzymes are present only in Lepidoptera larvae);
• age and biomass of the larvae (early instar⁶ larvae are more susceptible); and
• temperature (feeding rates and cell regeneration are inhibited by low temperatures).

2.1.5 Why is Btk used in preference to other subspecies of Bt?

Btk is used in moth eradication programmes because it is readily commercially available, it specifically targets the larvae of moths and butterflies (Lepidoptera), and it doesn't produce any toxic exotoxins⁷. Btk is the most widely used subspecies in Lepidoptera control.

2.1.6 What other ingredients are found in commercial formulations of Btk?

A distinction must be made between the bacterium Btk and commercial preparations based on Btk. Formulations of Btk are complex chemical mixtures, the exact ingredients of which are kept confidential for commercial reasons (although regulatory agencies have access to this information for assessment purposes). Commercial preparations may contain a large number of ingredients including spores, whole or partially degraded protein crystals, fermentation medium residuals, cell wall debris and trace amounts of vegetative cells (Seligy et al. 1997). Btk is cultured in large vats, which contain water and nutrients such as sugars, starches, proteins and amino acids. Small quantities of essential elements, minerals or salts may also be added to create good growing conditions for Btk (USDA 1995). Commercial formulations consist largely of water, Btk (figures of 2.1% to 2.5% by volume have been specified by two major manufacturers), and traces of these fermentation materials.

Other substances are also added to the formulations. These substances are known as "inert ingredients" to distinguish them from the "active ingredients" (Btk). Some common additives are:

• thickening agents (which provide uniform suspension in a spray);
• wetting agents (which provide better leaf coverage);
• phagostimulants (which encourage the insect to feed);
• anti-evaporants;
• stickers (to increase retention of spray deposits on leaves); and
• sunscreens (to decrease degradation of crystals by UV radiation).

Reference to the toxicity of inert ingredients is made in the Health Risk Assessment (Auckland District Health Board 2002).

2.2 What formulation of Btk would be used?

Foray 48B is manufactured by Abbott Laboratories in Chicago, USA. It is a flowable concentrate formulation (i.e., it is provided in liquid form) specifically designed for low volume and ultra low volume spraying.

Foray 48B has been registered for use in New Zealand under the Pesticides Act 1979 for use on forests, parks, shrubs and trees for the control of Asian gypsy moth and white-spotted tussock moth. The registration was extended in 2001 to include use on painted apple moth. It is used for both aerial and ground application (Foray 48B label information). It was used in the successful eradication campaign for the white-spotted tussock moth, Operation Ever Green in 1996-7.

2.2.1 Inert ingredients in Foray 48B

The USDA evaluated the inert ingredients in Foray 48B and found that they are all on US Environmental Protection Agency (EPA) Lists 3 or 4. List 4 contains substances which are "generally recognised as safe" and List 3 contains substances for which there is insufficient information to classify their safety (USDA 1995). The additives include substances to inhibit the growth of bacterial or fungal contaminants. These additives are approved for use in foods in the US and Canada. All of the inert ingredients have been assessed by the US EPA and various agencies in Canada with no public health threats from any of the ingredients identified (USDA 1995).

A Canadian publication has stated that the inert ingredients in Foray 48B include residual bacterial food (from potato, glucose or sucrose, corn or soya), sodium hydroxide (a pH adjuster used in chocolates, margarine and ice cream), potassium phosphate (a yeast food used by the wine industry) and a thickening agent (used in cream cheese and ice cream) (Agriculture Canada, c.1992). The manufacturer has indicated that Foray 48B contains no volatile solvents (Novo Nordisk, no date), and this has been confirmed by assessment authorities in New Zealand during the white-spotted tussock moth eradication programme (MOH 1996)⁸. A recent study by van Netten et al. (2000) examined the presence of volatile organic agents that could be released during spraying of Foray 48B, which could pose a potential health problem. The study concluded that the volatile agents with Foray 48B are not released into the air in any significant quantities from the bulk material and would therefore not pose a health hazard during spray operations.

2.2.2 Potential for contamination

One common concern about biological insecticides is that they may become contaminated with other micro-organisms such as yeasts, moulds and the faecal bacterium Streptococcus facecium. Since 1988, when strict quality control requirements were placed on North American manufacturers of Btk formulations, no substantial levels of bacterial or yeast contaminants have been found in Btk samples (USDA 1995). Each fermentation batch of Btk undergoes quality assurance tests for mammalian toxicity, microbial contaminants and formulation potency (Ellis 1991). The quality control measures are also designed to detect any changes in the Btk produced from the Btk parent strain. In addition, independent tests have confirmed a lack of contamination of the Btk formulation Foray 48B⁹.

Similarly, concerns that the close relationship between Bacillus anthracis and Bt could lead to contaminated broths is highly unlikely. Mammalian safety tests and other biochemically-based tests which are conducted on each batch would detect any B. anthracis.

2.2.3 Why would Foray 48B be used in preference to other formulations of Btk?

In some eradication programmes overseas, when public exposure to Btk was a consideration, formulations containing gamma-ray inactivated Btk spores were used. However, formulations of this type are not being used in New Zealand, as the need for inactivating the spores has never been demonstrated (BC MOH 1992) and irradiation of spores may cause additional public concern.

Other formulations of Btk, which are registered for use in New Zealand, are Agree, Delfin and Dipel. However, these formulations are registered for use only on horticultural crops.

Foray 48B is the preferred choice for a painted apple moth eradication programme in New Zealand as it is formulated and registered specifically for use on forests, parks, shrubs and trees. In addition, Foray 48B was used in the white-spotted tussock moth "Operation Ever Green" and has been widely used in Canada in gypsy moth eradication programmes, including programmes in urban areas, so there is a relatively large amount of information on potential environmental effects relevant to this formulation.

2.3 Where and how would the Btk be applied?

Decisions on the areas to be sprayed, how Btk will be applied and other operational matters are detailed in the painted apple moth project documentation.

3. The environmental impacts of spraying Btk

3.1 Introduction

This section identifies the actual and potential environmental impacts, both positive and negative, of the proposed Btk spraying programme. The term "environment" is used widely to include the natural and physical environment as well as effects on people (although human health issues are detailed in the Health Risk Assessment) and social, cultural and economic values.

The impacts addressed include those of the Btk formulation, and those associated with the spraying programme (aircraft noise etc.). Where available information permits, the impacts identified are specific to the Btk formulation proposed in Section 2 (i.e., Foray 48B). More commonly, the available information refers to the effects of Btk formulations generally, or occasionally, simply to Bt.

Each section in this chapter addresses potential impacts on one aspect of the environment. At the end of each section in this chapter, a conclusion is drawn about the likely impacts of a Btk spraying programme in New Zealand, based on the available information.

3.2 Sources of information

Identification of the potential impacts of Btk relies heavily on North American studies. This is inevitable, as it is in North America where Btk has been widely used in insect eradication programmes (e.g., for gypsy moth). Two sources, in particular, are quoted frequently in the following sections of the EIA. These are:

• BC MOH 1992 - a publication entitled "Bacillus thuringiensis" prepared by the British Columbia Ministry of Health as part of environmental impact information submitted in support of a gypsy moth eradication programme using Foray 48B in Vancouver in 1992; and
• USDA 1995 - a multi-volume environmental impact statement prepared by the United States Department of Agriculture, the Forest Service and the Animal and Plant Health Inspection Service on gypsy moth management in the United States. One of the methods of control discussed in this comprehensive document involves the use of Btk.

In addition, a recent book by two New Zealand scientists covers the potential environmental impacts of Bt in greater detail than can be covered in this assessment.

• Glare, T.R. and O'Callaghan, M. 2000. Bacillus thuringiensis; Biology, Ecology and Safety. John Wiley and Sons, Chichester, UK. 350 pp.

The World Health Organisation have also recently reviewed the environmental impacts of Bt (Anonymous1999. Microbial Pest Control Agent Bacillus thuringiensis. Environmental Health Criteria 217. World Health Organisation, Geneva).

3.3 How effective will Btk be in eradicating painted apple moth?

Bioassays of Foray 48B against painted apple moth have shown high potency (M. Kay et al., unpublished data). There are no previous examples of Btk being used to eradicate painted apple moth populations.

Painted apple moth is not a major pest in Australia or elsewhere in the world and, therefore, there have been no efforts to control or eradicate it. Information that is available on the efficacy of Btk in eradicating moth species relates to spray programmes to eradicate or control gypsy moth populations in North America. As gypsy moth is a relative of both painted apple moth and white-spotted tussock moth, the gypsy moth data provides the best available indication of the likely effect of a Btk spray programme on painted apple moth in New Zealand¹⁰.

3.3.1 Gypsy moth eradication programmes

In North America, Btk has been used for many years to eradicate and control gypsy moth populations, with inconsistent results. In British Columbia, monitoring information is available for 80 of the at least 102 separate gypsy moth introductions that have occurred in the past 18 years. 81.2% of the infestations died out by themselves and the remaining 18.8% were sprayed and successfully eradicated¹¹ (Environmental Appeal Board 1996). In some cases, eradication was achieved in one year. In other cases, two years of spraying were required. Failure of eradication programmes in the first year was often attributed to the area sprayed being too small (Agriculture Canada 1993).

A recent decision of the BC Environmental Appeal Board upheld an appeal against Agriculture Canada to ground spray Foray 48B. The main reason for declining permission to spray was that the applicant failed to show that the benefits of the spray programme outweighed the risks. In particular, the Appeal Board found that a ground spray programme alone was unlikely to eradicate the gypsy moth. The minor health risks associated with the use of Btk were balanced against the lack of demonstrable benefits of the ground spraying programme, and permission to spray was declined (Environmental Appeal Board 1996). As gypsy moth is so widespread in North America, some groups are now questioning the ability of Btk spray programmes to effectively eradicate the moth (e.g., see STOP 1995).

In the US, Btk is frequently used to control gypsy moth, rather than to eradicate it. US data on the efficacy of Btk shows that Btk spray programmes met their population reduction targets only 60% of the time in 1989-90. Since then, higher dose rates (60 BIU/ha¹²) and the use of undiluted formulations may have improved the efficacy of the programmes (USDA 1995).

Inconsistent efficacy of Btk has been attributed to the fact that it has to be ingested and has poor residual toxicity. These features tend to make efficacy more dependent on favourable conditions¹³. In the US, factors which were found to affect efficacy include correct timing of the applications with regard to insect and leaf development, weather conditions during and after application, and quality of application (e.g., good pilot skills, properly functioning equipment). The most important factors were making sure that Btk was applied to foliage on which the caterpillars were actively feeding, and applying the Btk in sufficient quantity to kill the insects (USDA 1995).

3.3.2 Likely effect in New Zealand

The New Zealand situation differs from the North American situation with gypsy moth in that the moth is not yet widespread. These factors both favour successful eradication. Results of the North American gypsy moth eradication programmes suggest that Btk is likely to be effective in eradicating painted apple moth in New Zealand, provided that:

• all infested areas are identified;
• a sufficiently large area around each infestation is treated with six to eight effective applications of Btk;
• dose rates are high enough to kill the insects (dose rates of approximately 60 BIU/ha are proposed);
• there are sufficient rain-free days at the ideal time of application; and
• the treatment is carried out by properly trained and equipped professionals.

3.4 How does Btk affect soil?

3.4.1 Persistence in soil

Bt occurs naturally in soils throughout the world¹⁴. The vegetative form of Btk does not generally persist in soil, and it requires the specialised habitat of susceptible insects to persist. However, Bt endospores can survive in most types of soils for extended periods. Experimentally determined half-lives of spores are usually in the range of 100-200 days (Hansen et al. 1996) and several studies have detected Bt spores in soil months to years after application. Estimates on persistence of Bt toxins vary widely; while it was previously thought that Bt toxins were inactivated within days in soil, there is some evidence to suggest that binding of Bt toxins to humic acids, organic supplements or onto soil particles protects the toxins from microbial degradation, without eliminating their insecticidal activity (Crecchio and Stotzky 1998). Retention of insecticidal activity can vary widely, depending on soil type.

Gribben et al. (2002) monitored the fate of Btk spores following aerial application of Foray 48B for control of white-spotted tussock moth in Auckland, 1997. Leaf litter and soil samples were collected from pre-spray and at 2 months post-spray (May 1997) and 2 years post-spray (October and December 1999). Samples were collected from 8 sites consisting of native vegetation and park environments. Prior to aerial application of Btk, no Btk-like isolates were found at any of the 8 sites (limit of detection <1 x 10³ spores /g soil). All samples collected 2 months after spraying contained Btk-like isolates, with populations ranging from 1.2 x 10⁴ - 8.5 x 10⁵ Btk-like spores /g soil. Samples collected from the same sites 2 years later showed similar results, with a slight reduction in the numbers of spores recovered from soil and leaf litter.

3.4.2 Accumulation and movement in soil

Repeated applications of insecticides containing Bt do not appear to increase levels of Bt activity in the soil. Bt applied to leaves for control of foliage feeding pests will become diluted well below insecticidal levels when it reaches the soil. The degradation rate in the soil would probably exceed the rate of acquisition from repeated foliar sprays, so populations of applied Bt reaching the soil should decline over time to a fluctuating natural level. Researchers have found that Bt does not move much in soil. This was determined by spraying two types of Bt in close vicinity. No cross-contamination of types was observed (BC MOH 1992).

3.4.3 Soil fertility and productivity

Changes in soil productivity and fertility due to Btk are not likely because of the natural occurrence of Bt in soil, lack of accumulation, and relatively short persistence of activity in soil (USDA 1995).

3.4.4 Soil micro-organisms

There have been few studies on the impact of Btk on soil micro-organisms. One North American study showed increased numbers of several soil micro-organisms (bacteria, actinomycetes, fungi and nematodes) in Btk treated areas when compared with untreated areas. Visser et al. (1994) examined the impact of Btk (Dipel 176) on soil microflora and decomposition processes. There was no effect on microbial respiration, soil biomass and soil processes such as cellulose decay at the recommended field rate. When applied at 1000x field rate, substrate induced respiration and biomass were increased over levels in the control soil. These experiments were of relatively short duration and it seems unlikely that the changes in microbial processes would be anything other than short-lived in field soils. Bernier et al. (1990) reported no effect of a strain of Btk on soil micro-organisms even at 100x the concentration recommended for aerial spraying. There was also no significant build-up of spores over a period of 11 months.

3.4.5 Likely effect in New Zealand

The information cited above suggests that Btk is unlikely to have any measurable effect on New Zealand soils although spores may persist for some time. No information is available regarding soil threshold levels and the effect on soil dwelling caterpillars (Porina) in New Zealand.

3.5 How does Btk affect water?

Bt may enter water through direct application to surface water, runoff, or through the faeces of animals who have ingested Bt. Following aerial application of Btk (Thuricide 16B) for control of a tortricid pest in eastern Canadian forests, Btk was recovered from rivers up to 13 days after spraying (Menon and de Mestral 1985), presumably as a result of continual leaching into the water.

3.5.1 Persistence in freshwater

Field studies indicate that Btk may persist for several months in water. A Nova Scotia study found that 50% of Btk endospores remained viable in fresh lake water for 70 days at 20^oC before being inactivated by other micro-organisms in the water (Menon and De Mestral 1985).

3.5.2 Persistence in seawater

Btk persists for a much shorter time in seawater. The study cited above showed that 50% of endospores survived only 40 days in seawater, possibly due to the bactericidal effect of seawater (Menon and De Mestral 1985).

3.5.3 Groundwater

It is unlikely that Bt could enter groundwater, as studies have shown that it does not leach out of soil (BC MOH 1992).

3.5.4 Water quality

Water quality should not be directly affected by Btk as it is not likely to affect most aquatic organisms. Some North American laboratory studies have shown decreases in detritus decomposition rates at high doses of Btk. However, these effects are unlikely in the environment because of the lower doses of Btk used and the purification processes in natural systems (USDA 1995).

3.5.5 Drinking water supplies

The Nova Scotia study referred to above detected Btk in a municipal water system during the spraying programme. This implies that chlorination of the water supply (a common means of ridding water supplies of bacterial contaminants) was not sufficient to kill the Btk - a finding backed up by laboratory studies (Menon and De Mestral 1985). It is possible, therefore, that a small amount of Btk may enter public water supplies as a result of aerial spraying programmes in areas which contain water catchments or water supply reservoirs. Btk contamination may also occur if spray enters air vents of local drinking water distribution reservoirs. Ingestion of Btk through water supplies is unlikely to have any adverse effects on human health as it is not a human pathogen (see Section 3.8 below for further details on human health effects).

3.5.6 Aquatic organisms

See Sections 3.6 and 3.9.

3.5.7 Likely effects in New Zealand

The information cited above suggests that Btk may be detectable in New Zealand water following a Btk spray programme, but is unlikely to have any effect on water quality. It is possible that Btk may be present in municipal water systems if spraying takes place near water supply catchments. Btk may also enter water supplies if spraying takes place in an area supplied by tank water. However, the presence of Btk in water is not considered to cause any adverse effects on human health.

3.6 How does Btk affect plants?

3.6.1 Terrestrial plants

Phytotoxicity (i.e., adverse effects on plant health) from Btk has never been observed at field rates of application (BC MOH 1992; USDA 1995). If anything, applying Btk is likely to have positive effects on the health of plants by reducing populations of leaf-feeding caterpillars. In some cases, however, this effect could be undesirable. For example, Btk may reduce the population of an insect imported for the biological control of a weed species, thereby allowing the weed to thrive. Plants which are pollinated exclusively or mainly by moths and butterflies may experience a temporary drop in seed set.

3.6.2 Aquatic plants

North American studies have found aquatic plants to be unaffected by Btk formulations (USDA 1995).

3.6.3 Likely effect in New Zealand

Btk is highly unlikely to have any direct toxic effects on New Zealand plants. Potential indirect effects on plants caused by Btk reducing Lepidoptera populations include:

_ positive effects on garden and other plants due to the reduction of leaf-feeding caterpillars (e.g., cabbage white butterfly caterpillars (Pieris rapae) will be killed by Btk if they are in a susceptible stage of development, thereby improving the health of some garden vegetables);

_ negative effects due to reduced populations of biocontrol agents. Lepidopteran biocontrol agents in New Zealand include the ragwort moth Tyria jacobaeae (introduced to control ragwort) and three species of moth recently introduced to assist in the control of gorse. Moths have also been introduced to control alligator weed and hieracium. Spraying with Btk could affect populations of the lepidopteran biocontrol agents in the area, but as with native moth populations, these effects would be limited to the duration of the spraying period, after which the agents would be expected to recolonise the area through migration¹⁵.; and

_ negative effects on plants pollinated by moths and butterflies. Again, it is unlikely that spraying with Btk would have any adverse effects on native plants, as New Zealand's native plants are generally unspecialised in terms of pollination (i.e., they are not reliant on single specialised forms of pollinator) (Wardle 1991). Introduced plants are also unlikely to be affected in the long term by reduced pollination, although those species that are solely reliant on moth or butterfly pollination may undergo a decrease in pollination during the spraying programme. Moths and butterflies are expected to recolonise the area when spraying ceases.

3.7 Does Btk leave a residue on crops or other sources of food?

3.7.1 Persistence of spores on foliage

Estimates of persistence of Btk spores on foliage vary from hours to several weeks, and typically the half-life¹⁶ of spores on foliage is much shorter than in soil. Hansen et al. (1996) reported that experimentally determined half-lives were usually in the range of less than one to three days and these estimates are supported by many field studies. Pedersen et al. (1995) showed an initial half-life (1^st week) was 16 hours for Btk applied to cabbage foliage, with numbers declining by five log units during the first four weeks after spraying. Similarly, Btk (in Foray 48B) spores applied to needles of Pinus in Lithuania decreased rapidly in the first 1-2 days, bacterial mortality reached 68% after 2 days on needles and 88% by 5 days (Bartninkaite and Ziogas 1996). In another study, Smith and Barry (1998) examined persistence of Btk after applications in Utah (72 BIU per acre per year for 5 years for eradication of gypsy moth). They found that while spores persisted in soil for over two years, there was no difference in the numbers of Bt spores on sprayed and unsprayed leaves sampled 12 months after application.

3.7.2 Persistence of Bt toxin activity on foliage

Persistence of Bt toxin activity at operational doses in the phyllosphere has been well studied. Since crystals survive damage by UV radiation in sunlight much better than spores, insecticidal activity reflects activity of crystals because viable spore numbers can be considerably reduced without significantly lowering activity against most insects. In the phyllosphere, the half-life of toxins can be as short as one day (Hansen et al. 1996). Several field studies have detected short residual activity on foliage, while in contrast other studies have demonstrated insecticidal activity for quite long periods. This was at least 64 days in a study on the foliage of Douglas Fir (Miller and West 1987), up to 18 days on Prunus (Hamed 1978) and several studies have shown one to two days is normal. One study showed activity

in stored grain of up to 255 days (Salama et al. 1995). Persistence of toxin activity varies in response to many factors including environmental conditions, type of foliage, formulation used etc. Persistence on various types of foliage has been reviewed in Glare and O'Callaghan (2000).

3.7.3 Presence on vegetables

Btk occurs naturally in the New Zealand environment. As part of a major study on the effects of Foray 48B Btk aerial spray programmes in Vancouver, food samples were analysed for Btk. The researchers were able to cultivate Btk from a variety of vegetables during and after the spray programme. They concluded that it was most unlikely that all of the Btk on the food came from the aerial spraying programme (Noble et al. 1992).

Effects of the presence of Btk in food on human health appear to be negligible as Btk does not grow in warm blooded organisms and passes through the digestive system without producing any toxic effect. This is indicated by the lack of human health effects demonstrated in several studies (see Section 3.7) and by the fact that Bt is exempt from any requirements for a maximum residue limit when applied to crops (BC MOH 1992 and NZ Food Regulation 275 (15)).

Bt is closely related to the bacterium Bacillus cereus, which can cause food poisoning in humans. Pathogenicity of B. cereus, in terms of food poisoning by diarrhoeal enterotoxins, is caused by ingestion of vegetative cells rather than pre-formed enterotoxin. Therefore, the product contents of Bt insecticides, spores and endotoxins are not considered toxic to mammals. The most recent Re-Registration Eligibility Decision documents released by the Environmental Protection Agency, USA (EPA, 1998) stated that the agency has no valid evidence to link actual usage of Bt insecticides with episodes of diarrhoea following ingestion of food.

3.7.4 Cumulative effect in the food chain

Btk is unlikely to have any effect in food chains because it has not been found to replicate or accumulate in predators (BC MOH 1992).

3.7.5 Likely effect in New Zealand

The New Zealand situation is likely to be similar to that found in Vancouver, that is, the population is exposed to sources of Btk in food other than aerial spraying. A number of Bt formulations are registered in New Zealand for use on kiwi fruit, citrus trees, grapevines and berry fruit. Btk formulations have been approved for use in organic agricultural regimes and are relatively widely used on organic crops. It is therefore unlikely that an aerial spray programme for painted apple moth would have any significant effects on Btk residues on food. However unintentional spraying of organic crops with Foray 48B may result in the loss of certification for the affected crop.

3.8 What effects may Btk have on non-target invertebrates?

Non-target invertebrates are any invertebrates (i.e., animals without backbones such as insects, spiders, crustaceans, molluscs) other than the target organism (painted apple moth). These organisms may be exposed to Btk either directly by encountering it in the environment (e.g., by eating leaves, litter, or the uppermost layer of the soil) or indirectly, by eating caterpillars which have been infected with Btk. Aquatic invertebrates may also be exposed to Btk through direct application of the spray to water or run off, but few studies have examined the effect of Btk on aquatic ecosystems. The few studies reported have generally found few effects on aquatic invertebrates (Kingsbury 1975; Eidt 1984; Kreutzweiser et al. 1992; 1994; 1996), even at 10x the normal concentration.

Evidence from ecosystem studies in the USA show that even among Lepidoptera populations affected by Btk sprays, populations rebounded within two years (Glare and O'Callaghan 2000).

The toxicity range of Btk is wider in laboratory bioassay than found in the field. It can be toxic to some Coleoptera, Diptera and Hymenoptera in the laboratory, but it is clearly more toxic to Lepidoptera with 234 genera recorded as containing susceptible species (Glare and O'Callaghan 2000).

3.8.1 Caterpillars

Btk is expected to kill all exposed early instar caterpillars (i.e., caterpillars which have hatched relatively recently) located within the target area and in adjoining areas that are exposed to spray drift. More than 300 moth and butterfly species have been reported as having caterpillars that are susceptible to at least one isolate of Btk (Glare and O'Callaghan 2000), but dose rate, life cycles of insects, inherent variability within species with regards susceptibility all contribute to reduced non-target impacts with field use.

In the US, Btk spraying commonly resulted in an 80% reduction in the number of caterpillars, with population recovery taking up to two years (Abbott 1994). Other US reports indicate that, although data are sparse on the effects of multiple applications of Btk within one year, it is reasonable to expect that both the numbers and types of non-target caterpillars may be reduced and that these effects could persist for one year or longer (USDA 1995). One study (Miller 1990) that did address multiple applications of Btk within a year was carried out in Oregon in 1986-88. It found that the number of species of leaf-eating Lepidoptera was significantly reduced for three years after spraying with Btk, and the number of individual non-target caterpillars in the trial area was significantly reduced for two years. Factors which influenced the ability of non-target species to recover included the stage of larval development at the time of spraying, the number of generations in a year (species with a single generation take longer to recolonise), and the insect's ability to disperse.

Permanent changes in non-target caterpillar populations do not appear likely except, possibly, in habitats that support small isolated populations of Lepidoptera that are highly vulnerable to Btk. This is particularly so if there are physical or biological barriers which may prevent the insect from moving back into the sprayed area (USDA 1995).

In some well-studied species (e.g. gypsy moth), caterpillars which are exposed to Btk but do not die, grow more slowly and remain in the larval stage for longer periods, and therefore may be more susceptible to parasites (USDA 1995).

Halwas (2001) and Boulton et al. (1999) reported on a study on non-target Lepidoptera on Garry Oak and common snowberry within the Vancouver Island spray area of 1999. Most lepidopteran species appeared to reduce in numbers 4-5 weeks after application of Btk. Individual species were collected too infrequently for analysis. Total lepidopteran abundance and species richness were significantly reduced by Btk compared to control plots in both the year of spraying and the next year. Not all species were affected equally.

It is likely that the aerial application of Btk will impact on non-target Lepidoptera within the area treated.

It is noted that extinction of sensitive, rare species is one potential outcome of the spray treatment. Fortunately, most rare moth or butterfly species (cited in Appendix 1) will have reservoir populations outside the treated area and will thus survive in the long-term. Common species will move back in. the balance of species diversity will probably shift in favour of common, vagile species as a result of repeated spray treatement.

3.8.2 Beneficial insects

Many studies have been carried out on the effect of Btk on honeybees. The overall conclusion of these studies is that Btk is non-toxic to bees, even at high levels of exposure (Ellis 1991; Lehnert and Cantwell 1978). At field rates, no impacts have been reported.

Invertebrate parasites and predators which feed on Btk-infected insects may experience temporary decreases in population numbers. These decreases may be caused by lack of food supply, rather than Btk toxicity. The fact that Btk does not affect natural caterpillar predators and parasites is one reason why it can be successfully used in integrated pest management programmes (Ellis 1991). Glare and O'Callaghan (2000) reviewed a number of studies on predators and parasites of insect pests; Btk was rarely considered harmful. In 70 of 87 predator studies little or no effect was shown, the remainder showed effects such as reduced egg laying, delayed growth, or delayed mortality in the next generation. Direct toxicity was very rare. Similarly, in parasites direct toxicity was very rare. Of 153 individual studies 114

showed no effect or increased parasitism (Glare and O'Callaghan 2000). Others showed some effect, often as a result of competition between Bt and parasitoids for a cadaver.

3.8.3 Other insects and spiders

Studies have shown that Btk does not affect the overall abundance of beetles, sucking insects such as aphids, leaf hoppers, cicadas or spiders. Neither are immature and adult stages of mayflies, caddisflies, dragonflies, damselflies, midges or dobsonflies generally affected (USDA 1995). However, a blackfly (known as sandfly in New Zealand) and a stonefly species were affected by Btk in a laboratory study and a mayfly population decreased after Btk was applied in a field study (USDA 1995). In a field study, a stonefly species was the only one of 12 aquatic insects significantly affected by Btk (Kreutzweiser et al. 1992).

A number of field studies have shown no appreciable adverse effects on the abundance and composition of aquatic invertebrates following Btk application (USDA 1995), even at dose rates more than 10-100 times greater than those which would occur during normal Btk treatments (Perrin and Richardson 1993). However, while there have been no studies specifically on aquatic lepidopteran caterpillars in the USA (USDA 1995) in New Zealand only one wide-spread aquatic species (Hygraulia nitens) is know. H. nitens is widespread and common and would not be under threat from Btk treatment. Invertebrates in marine and estuarine environments are also unaffected by Btk (USDA 1995; Glare and O'Callaghan 2000).

3.8.4 Earthworms

Experiments involving earthworms and the Btk formulation Dipel found no significant difference in worm density between treated and untreated plots, even when the Btk was applied at a rate 100 times greater than the recommended dose for field application (Ellis 1991). Addison and Holmes (1996), however, reported 1000x concentration of a formulation of Btk (Dipel 8L, formulated in oil) reduced survival, growth and cocoon production of earthworms, although another formulation (Dipel 8AF formulated in water) did not.

3.8.5 Other invertebrates

Other invertebrates which field studies show to be unaffected by Btk include planaria, flatworms, nematodes, roundworms, leeches, crustaceans, crayfish, water mites, snails¹⁷, clams and mussels (these were studied in a stream in Ontario) (Ellis 1991). Further studies indicate that Btk is not toxic to shellfish (including oysters, mussels and periwinkles) and shrimp (Ellis 1991).

3.8.6 Insects reared for scientific, domestic or commercial purposes

Any business involved in rearing moths and butterflies commercially, for example butterfly farms, would carry a heavy risk of damage if located within or near a spray area. Scientific institutions with insect rearing facilities for biological control work or study of Lepidoptera species would similarly be at risk.

School biology classes or private individuals rearing caterpillars, such as monarch butterflies on swan plants, could expect caterpillar mortality if they were exposed to the spray. Because there is a residual population of these insects there will be a gradual return of the natural population once spraying operations have been completed.

3.8.7 Likely effects in New Zealand

North American studies confirm that members of Order Lepidoptera (moths and butterflies) are generally the only invertebrates that are likely to be significantly affected by application of Btk. Commercially important species such as honeybees are not at risk from Btk. Similarly, there is no reason to suspect that other insects, including New Zealand species for which no overseas data exists, or other invertebrates, including earthworms, snails and crustaceans (e.g., crayfish) will be affected by Btk.

New Zealand has 1761 recorded species of Lepidoptera. This figure includes 63 vagrant species (recorded in New Zealand only occasionally) and 73 species introduced since European settlement (Dugdale 1988). An additional study by Robert Hoare (Landcare Research) has been carried out to assess which native genera of Lepidoptera would be at risk from Btk (Hoare, 2002).

If an area to be sprayed contained indigenous Lepidoptera species with restricted distributions, Btk may have an adverse impact on those species. Further detail of species likely to be affected cannot be provided except on a case-by-case basis, depending on the location and time of spraying. If there were Lepidoptera species present in an area to be sprayed which were:

• rare or endangered; or
• an isolated population (i.e., could not be re-established from nearby populations) or
• at a vulnerable developmental stage; or
• poor dispersers;

then these species could be absent from the sprayed area for a number of years unless active steps were taken to re-introduce them (see Section 4.10).

There have been several reports of lepidopteran species found within the predicted spray area which are rare (listed in Appendix 1). In addition, Richard Newcomb et al. (pers. comm.) of HortResearch has identified two leafroller species in the mangroves on Pollen Island which would be at risk from Btk application. One is the mangrove leafroller, Planotortrix avicenniae, which is also found over the northern half of the North Island and, therefore would be likely to re-invade after the spraying. Another leafroller has recently been discovered on Pollen Island, a strain of Ctenopseustis obliquana, a species better known as a pest of horticultural crops. This strain appears to have recently evolved to mangroves and seems to be only present on Pollen Island (Newcomb, Dugdale and Sirey, pers. comm.). It is possible Btk will affect this novel population, if spraying includes the mangroves. Other lepidopteran species listed in appendix 1 could be at risk from spraying. Targeting spraying as opposed to blanket aerial application is one method to reduce risk to these species.

For most Lepidoptera species, however, even if the larvae were at a critical stage at the time of spraying, and there was 100 percent mortality in the sprayed areas, it is likely that the areas would be re-colonised within one to three years¹⁸. The sprayed areas would not be "Lepidoptera-free zones" after spraying, as species which had late instar larvae present, or were present as adults, would not be affected.

Safeguards for reducing adverse effects on commercial or scientific moth or butterfly-rearing activities are addressed in Section 4.10

3.9 Spray drift and penetration of houses

In a study on distribution of Btk spores after aerial application over Vancouver island of Foray 48B, Teschke et al. (2001) found that during spraying, an average of 739 colony-forming units/m³ of air was detected. Outdoors, this figure decreased quickly over time, reducing by half in 3.3 hrs. It could still be detected outdoors after 9 days, but at reduced amounts. Btk spores could be detected within houses with an average concentration of 2-5 times lower than outdoors initially, but exceeding outdoor concentrations within 5-6hrs.

Btk was detected 125-1000 m outside the spray zone, dependent upon wind speed and direction more than other factors such as distance from the spray zone (Teschke et al. 2001). In another study, aerial application of Btk (Dipel) from a helicopter resulted in mortality of sentinel insects up to 3km from the spray zone (Whaley et al. 1998).

3.10 Does spraying with Btk affect animal health?

The two main issues considered in this section are first, the effects of Btk formulations on animal health (this includes direct effects of contact with Btk as well as indirect effects as a result of feeding on insects treated with Btk), and secondly, the effects of other aspects of the spray programme on animal health.

Animals may be exposed to Btk through ingesting Btk on plants, ingesting insects infected with Btk, inhaling Btk spray, or through skin (dermal) contact with the spray. The mode of action of Btk (i.e., it is activated by the specific conditions in the insect gut) means that there are no concerns about dermal contact and inhalation in animals (USDA 1995).

3.10.1 Effects on mammals

There are many references dealing with the possibility of toxicity or pathogenicity of Bt spray products, and all of the references consulted during the preparation of this EIA suggest that Btk is of no risk to mammals. Laboratory experiments have confirmed that Btk does not grow in warm blooded animals (Hayes and Laws 1991). Review of mammalian toxicity of Bt by the US Environmental Protection Agency (McClintock et al. 1995) concluded that no adverse effects have been demonstrated in acute toxicity studies with small mammals. Following oral and pulmonary dosing, Bt spores were generally cleared from animals rapidly, with no adverse effects. Some mortality was observed in mice following intraperitoneal injection of high doses (10⁸ colony-forming units/animal), but the same isolates have been shown to be non-toxic at 10⁷ cfu and below. By comparison, high doses of bacteria generally regarded as non toxic, such as Bacillus subtilis, can cause mortality if used at rates exceeding 10⁸ cfu/animal).

The effects of Btk on mammalian predators feeding on Btk-treated insects have not been well studied, but available literature suggests that there are no adverse effects. Btk is unlikely to have any effect in food chains because it has not been found to replicate or accumulate in predators (BC MOH 1992).

Mammals, including bats which feed on susceptible insects, might be affected indirectly by reductions in food abundance due to Bt sprays. This may trigger a change in diet. However, unlike the situation following treatment with many conventional pesticides, insect feeding mammals are not adversely affected by ingestion of moribund insects killed by Bt.

3.10.2 Effects on reptiles and amphibians

There is little information on the toxicity of Btk to reptiles and amphibians, but the available information that does exist suggests that they are not at risk from Btk (USDA 1995).

3.10.3 Effects on birds

No significant toxicity of Bt strains to any bird species has been recorded. Several laboratory studies on toxicity of Btk and other subspecies to mallard duck and bobwhite quail were summarised in Re-registration Eligibility Documents (EPA 1998). The EPA concluded that these subspecies were not toxic or pathogenic to the mallard or the quail after acute or subacute testing. Other studies indicate that Btk has no effect on domestic birds such as chickens, even if they are fed Btk directly (Ellis 1991).

Several studies have found no significant reductions in bird populations in areas treated with Btk (BC MOH 1992). Studies in Manitoba and Ontario of 74 bird species representing 21 families showed no significant reductions in bird numbers (Ellis 1991) and other more recent studies have found few adverse effects (e.g. Holmes 1998; Nagy and Smith 1997). However, impacts on bird populations have been noted in some studies. Rodenhouse and Holmes (1992) showed a reduction in biomass of lepidopteran larvae after application of Bt led to significantly fewer nesting attempts by certain birds.

An assessment of the potential impacts of an early Vancouver spray programme on songbirds concluded that there would be negligible mortality of adult birds and the most severe potential effect would be a localised decrease in breeding success of a few species which are most highly dependent on Lepidoptera for food. This was not considered to produce any detectable change in bird numbers the following year (Weber 1993). The USDA concluded that field studies show the effects of Btk spraying on insectivorous birds to be "subtle"(USDA 1995).

Sopuck and Ovaska (2001) examined the effect of caterpillar reductions on songbirds during a Vancouver eradication programme for gypsy moth using Foray 48B in 1999-2000. They concluded that spraying Btk had few or no detectable effects on songbird abundance. Of 44 songbirds in the spray zone which were considered to include caterpillars in their diet, any change in numbers was detected with only two. The Spotted Towhee occurred in significantly fewer numbers in sprayed than unsprayed plots in 1999, but this did not coincide with peak decrease in caterpillar numbers. Short-term impact of the spray application is a possible explanation for this short-term decline. Adult Bushtits were also consistently fewer in the spray zone compared to unsprayed, but the authors thought this could be attributed to variations in habitat between the two sites.

Sopuck and Ovaska (2001) recommended that to reduce impact on birds, aerial spraying should be targeted to areas only known to have larvae and eggs of the pest (in their case gypsy moth).

3.10.4 Effects on fish

Most fish are unlikely to be affected by Btk. There is some suggestion, but no evidence, that fish which have alkaline digestive systems such as carp or koi may be adversely affected by Btk (USDA 1995).

A trial conducted with Foray 48B in British Columbia found the formulation to be lethal to rainbow trout at high concentrations (26 600 ppm). At the specified rate of application, or in a worst case over-spray scenario, rainbow trout were not affected. However, the researcher expressed concern at the potential adverse effect that the acidity of the product (pH 4.3, regardless of the level of dilution) could have on fish populations in the event of a spill into a waterway (Watts 1992).

There has been no documented evidence of any fish kills as a result of the many forestry, agricultural and urban spraying programmes involving Btk in Canada and the US in the last 20 years. This suggests that sources of fish food are not significantly affected by Btk (Ontario Ministry for the Environment 1989). Field studies have found that Btk-contaminated water has no observable effects on fish behaviour and reproduction, and there is no evidence that consumption of Btk-treated insects has adversely affected fish to any noticeable degree (USDA 1995 and Ontario Ministry for the Environment 1989). No references were found which indicated any adverse effect on marine fish.

3.10.5 Other effects of the spray programme on animals

Perhaps the greatest effect of the spray programme on animals will be through aircraft noise. Animals particularly sensitive to this type of effect are pets, horses and stock.

3.10.6 Likely effects in New Zealand

Mammals

New Zealand's two species of native bats (the short tailed bat and the long tailed bat) both include Lepidoptera in their diet (Nowak 1994). The short tailed bat has a very broad diet and so would not be affected by any temporary reduction of Lepidoptera populations caused by Btk. The diet of the long tailed bat consists of mosquitoes, moths and midges, so it may be affected to a greater extent by low Lepidoptera population levels.

No information was found during the preparation of this EIA on the effects of Btk on marine mammals, but there is no reason to believe that there would be any adverse effects on whales and seals.

The greatest impacts of the Btk spray programme on mammals in New Zealand appear to be the effects of noise from low-flying aircraft on vulnerable domesticated mammals.

Reptiles and amphibians

A study of New Zealand frogs (native species and the introduced whistling frog) found that 0-5% of their diet consisted of Lepidoptera (Kane 1980). New Zealand's native lizards (geckos, skinks and tuatara) also eat a combination of insect species and other small invertebrates and Lepidoptera would form a small (if any) part of their diet. Frogs and lizards are therefore unlikely to be affected by reduced Lepidoptera populations resulting from a Btk spray programme.

Birds

Although the North American studies on bird toxicity did not include bird species native to New Zealand, no long term adverse effects on native birds would be expected.

There may be some effects on birds which rely heavily on Lepidoptera or lepidopteran larvae in their diet, but these effects are likely to be temporary and behavioural rather than significant. Following a Btk spray programme, these birds may have to increase their foraging range (possibly to include areas outside the spray zone) and the time spent looking for food. Other native species, such as fantail, catch their insect prey on the wing. The effects of reduced Lepidoptera numbers are likely to be greatest on birds such as fantails, as Lepidoptera make up a large proportion of their diet, and the birds are territorial and do not forage far for food. If spraying occurred in spring, it is likely that at least some of the species mentioned above (particularly, grey warbler, silvereye and fantail) would be unable to breed successfully in the sprayed area that season due to reduced food supply. However, these effects will be temporary and the bird population should recover as soon as food supplies return to normal levels (DOC 1996¹⁹).

Pollen and Traherne Islands are two areas of special conservation interest with respect to wildlife. The Department of Conservation reported, in evidence to a Resource Management hearing for a heliport establishment application (Chris Green, pers. comm.), that Pollen Island was part of an important marine reserve. Btk would be unlikely to affect marine organisms and impacts of Btk would most likely be less than other potential control methods such as Decis (deltamethrin) application. According to Green, many of the birds would be unaffected by Btk as they are marine wading birds that don't feed on lepidopteran species but feed on soft bodied invertebrates. However, there is potential for aerial spraying activities to impact on bird species nesting on the islands and feeding on the mudflats. It is possible that noise from aircraft could frighten birds off their nests during nesting season on Pollen Island. Of particular concern is the New Zealand dotterel, a threatened species. The extent of this impact will depend on the frequency of aerial application, with infrequent sprays (i.e. one spray every three weeks) unlikely to cause problems for the birds. It may be necessary to consider timing of breeding season when spray applications are planned.

Fish

Similarly, there is no information in the American studies to indicate that New Zealand fish may be affected by spraying Btk. However, the unconfirmed suggestion that fish with alkaline digestive systems, such as carp, may be affected by Btk is of potential concern, as grass carp are sometimes used in lakes and ponds to control weed growth (see Section 4.11). The main risk to fish in New Zealand is posed by an accidental spill of Btk formulation into a waterway. This possibility, and means for preventing it, are discussed in Section 4.4.

3.11 What are the likely effects on amenity values?

Amenity values are "those natural and physical qualities and characteristics of an area that contribute to people's appreciation of its pleasantness, aesthetic coherence, and cultural and recreational attributes" (Resource Management Act 1991). Effects on amenity values are often known as "nuisance effects". The WHO defines nuisance as "occurring when life is less pleasant than it would otherwise be without affecting health in the medical sense".

The main potential effects of a Btk spray programme on amenity values are the visual effect of the spray from aircraft, noise from aircraft, and odour. There are also positive effects on amenity values which arise from eradicating a pest which is able to defoliate urban trees and bushes.

3.11.1 Likely effects in New Zealand - visual effect of spray

The Btk sprayed from aircraft would be perceived as a very fine mist for a short duration (approximately 10 minutes). The spray would be seen (if spraying takes place in daylight) and felt in the area of direct application and, to a lesser extent, in any area affected by off-target spray drift. The area affected by off-target spray drift would depend on the height of the aircraft, windspeed and droplet size, but is unlikely to be greater than 300m from the downstream edge of the sprayed area²⁰.

3.11.2 Likely effects in New Zealand - noise and other effects of low-flying aircraft

The physical effect of aircraft flying at low altitudes over urban areas is likely to be the most significant effect of the spray programme on people. The level of noise impact will depend on:

• the type of aircraft used in the spray programme;
• the height and speed at which the aircraft fly; and
• the time of day at which spraying takes place.

The selected aircraft for the eradication programme is a Fokker Friendship (F27), a twin engine helicopter (BK117) and a smaller fixed wing Air Tractor (AT 602). Background noise levels vary depending on the time of day and the nature of the target area. In residential areas, the background noise levels in the very early morning are approximately 30-60 dBA. Aircraft noise of 90-100 dBA would therefore be experienced as a very significant intrusion although of a limited duration. At these noise levels, people would be woken from sleep.

However, if noise levels reach 110 dBA, the effects could become more significant. A period of three seconds of exposure to a level of 110 dBA represents the maximum daily exposure permitted at this level in an industrial setting. Child hearing could suffer initial damage at this level and, as the onset of the noise is likely to be very rapid, at levels of 110 dBA some heart conditions could be aggravated²¹ (Ministry of Health 1996²²).

In addition to noise effects, some helicopters, when flown at very low heights (10m) can cause significant negative effects from downwash at higher flying heights these effects become unnoticeable. Civil Aviation Authority requirements for the painted apple moth operation are that aircraft fly not below 50m (or 150 feet) over residential areas, and there are no speed restrictions on the aerial operation. The final aerial operational decisions are largely determined by the need to minimise the negative effects of the operation.

3.11.3 Likely effects in New Zealand - odour

It is highly unlikely that any persistent odour from Foray 48B could be detected after a spray operation.

3.12 Have any other potential social, economic or cultural impacts been identified?

3.12.1 Public concerns about spray programmes

When agrichemicals are sprayed from aircraft in urban areas, there is always a degree of public apprehension and anxiety (California Department of Food and Agriculture 1992).

Surveys of public opinion carried out as part of the US environmental impact assessments on the management of gypsy moth identified that people were (USDA 1995 and California Department of Food and Agriculture 1992):

• anxious and fearful about the appearance of helicopters and planes used to spray insecticides;
• anxious about the safety of insecticides and distrustful of government claims about insecticide safety or government actions to control insect pests;
• concerned and angry about "involuntary exposure" to pesticides;
• concerned about possible effects on their physical health;
• concerned about the risks of insecticide spills, plane accidents and car accidents related to the spray programme;
• concerned about workers being exposed to traffic, power lines, dogs, and rough neighbourhood conditions;
• affected by disruptions to their normal routines;
• worried about government expenditure on eradication programmes; and
• concerned about the potential environmental effects of spray programmes.

Other potential causes of stress or fear are lack of understanding of the reasons for spraying and lack of information on the substance being used and its possible effects on human health. For some people, the sound of helicopters approaching may be deeply distressing if it recalls memories of living or serving in combat zones (MOH 1996²³).

Authors of the EIA on the Californian gypsy moth programme noted that "anxiety will never be eliminated entirely. Many individuals feel threatened because, if impacts they are concerned about materialise in the future, serious consequences might result. Regardless of how much data has been collected which does not show these theoretical impacts, some would prefer not to allow the use of any pesticide in the public sector..." (California Department of Food and Agriculture, 1992).

In general, people in rural agricultural areas are less likely to be concerned about spraying to control insect pests because of their familiarity with the spraying of agricultural crops (USDA 1995).

3.12.2 Likely effects in New Zealand - social concerns

It is likely that the concerns identified in Section 3.13.1 above will be felt by some people in New Zealand. Steps to address these concerns have been taken by MAF and through consultation with the community.

3.12.3 Likely effects in New Zealand - issues of concern to Maori/Treaty of Waitangi issues

Concerns were raised by representatives of Te Kawerau a Maki as to the potential effects from Btk spray on their taonga and waahi tapu. Potential issues which were considered included effects on water quality, effects on native plants used for cultural purposes, effects on kaimoana (sea food) or other food resources, and health effects which may have a greater impact on the Maori population. There are no indications of significant physical adverse effects from Btk in these areas.

3.12.4 Likely effects in New Zealand - other cultural effects

No issues of particular concern to any other cultural groups in New Zealand have been identified during the preparation of this EIA. However, as noted in Section 3.11.1 above, some cultural groups in New Zealand, because of previous exposure to helicopter noise in war situations, may find the noise associated with a Btk spray programme particularly distressing.

3.12.5 Likely effects in New Zealand - economic activity

No significant adverse effects on economic activities arising from the spraying of Btk have been identified during the preparation of this EIA. It is not considered that there would be any adverse effects on tourism, agricultural, horticultural or viticultural activities as a result of the painted apple moth eradication programme. However, while no certified organic producers have been identified in the painted apple moth zone there are potential impacts for organic producers as Foray 48B is not a certified organic product (although Btk is a permitted pest management material). If a certified organic property is sprayed as a result of the eradication programme its organic certification could be lost for 12 months (or longer). If any certified organic producers are identified, current MAF practice would be to work with the producer to avoid any potential impacts. Generally, positive economic effects are expected as a result of the eradication programme, as the presence of painted apple moth in the New Zealand environment has a significant economic cost (see Section 5.2).

3.12.6 Likely effects in New Zealand - safety

Traffic safety

There may be an increased risk of traffic jams and road accidents due to sunglare from spray on windshields and distraction by low-flying aircraft²⁴. This risk will be addressed as part of the communications strategy preceding any eradication programme and through liaison with traffic control authorities.

Aircraft safety

The safety of low-flying aircraft is addressed in the conditions placed on low level operations by the Civil Aviation Authority (see Section 4.2.4). Potential hazards for low-flying aircraft include power lines, trees and television masts.

3.13 Are any particular environments more sensitive to the effects of spraying with Btk than other environments?

There are some receiving environments (i.e., areas in which Btk may be applied) that may be more sensitive to the effects of a Btk spray programme than others. Some of these sensitive environments have been identified in preceding sections of this chapter. Environments which may be particularly sensitive to Btk formulations include:

• biologically sensitive environments (e.g., environments which contain rare or isolated populations of sensitive insects, or environments which contain rare or threatened populations of species which are heavily reliant on vulnerable insect species as a food source);
• socially sensitive environments (e.g., hospitals, schools, marae); and
• economically sensitive environments (e.g., butterfly-rearing operations).

Environments which may be particularly sensitive to noise associated with the spray programme include hospitals and businesses involving noise-sensitive animals (e.g., stud farms, zoos).

All environments (particularly waterways) are potentially sensitive to adverse effects arising from an accidental discharge of Btk (i.e., a spill). These effects are of low probability but high potential impact.

Means for reducing potential impacts on sensitive environments are addressed in Section 4.10 and means for reducing the occurrence and effects of Btk spills are addressed in Section 4.4.

3.14 Could there be any cumulative or long term effects?

3.14.1 Genetic stability of Btk

A common concern with biological pesticides is their genetic stability (i.e., whether they remain true to their parent strain). Btk is a living organism, and although the potential exists for mutagenic changes, the chances of mutation are exceedingly low. The chances that a mutation may cause Btk to infect species other than Lepidoptera are even lower. This conclusion is based on the observations that:

• pathogenic mutations of Btk have not been demonstrated (BC MOH 1992);
• widespread Btk-induced epizootics are very rare (BC MOH 1992); and;
• an early study which attempted to induce harmful mutations in Bt by serial passage through mammals, found no increase in virulence to mammals (Ellis 1991).

3.14.2 Resistance of painted apple moth to Btk

There is an extensive literature on the development of resistance to Btk in Lepidoptera (reviewed in Glare and O'Callaghan 2000). One significant case of field-developed resistance has been documented. This was for the diamondback moth and has been reported in several countries. In the laboratory, it has been relatively easy to develop Bt-resistant insects after exposure in less than 20 generations. This requires constant exposure to sublethal doses, which is far harder to achieve in the field than the laboratory. The painted apple moth eradication programme is unlikely to apply sufficient selection pressure for painted apple moth to develop resistance to Btk.

3.14.3 Cumulative effects of Btk treatments

Potential cumulative effects of Btk include residual exposure to Btk formulations after a single exposure, multiple applications in a single season, and multiple applications over several years.

Btk can persist in some environments, such as soil, although toxicity is rapidly inactivated by UV radiation and other micro-organisms (see Sections 3.4 and 3.7). There is increasing evidence that Btk toxins can bind to soil particles such as clay, but the environmental effects from a build-up of Bt toxins in soil have not been reported.

Multiple applications in a single year are likely to have greater impacts on vulnerable non-target insect populations than single applications, but are still unlikely to prevent recolonisation by those species within three years.

A recent study on spore persistence of Btk after Operation Ever Green (Gribben et al. 2002) found that there was only limited reduction in bacterial spore numbers in environmental soil samples over the two-year post-spray period. However the ability of Btk to participate in the microbial community is dependent on its ability to germinate, grow and sporulate. Growth and sporulation were strongly influenced by physical soil conditions and Btk will persist in soil under certain conditions of pH and nutrient availability. There is some potential for cumulative effects on non-target organisms if a spray programme is repeated over a number of years (USDA 1995) but again, the Oregon study indicates that many sensitive insect populations return to roughly pre-treatment levels in three years (Miller 1990)

4. Preventing or reducing any adverse effects

4.1 Introduction

This section of the EIA sets out measures that will be used to help prevent or mitigate the actual and potential effects of spraying Btk identified in Section 3 of the EIA.

4.2 Legislation and other requirements

The provisions in legislation, plans and policies can be used to help manage the environmental impacts of Btk spray programmes. Several different types of approvals and consents are required in order for the eradication programme to proceed. These approvals are summarised in this section. The Acts, plans and policies of relevance to the proposed painted apple moth eradication programme are:

• the Forests Act 1949 and the Forest Disease Control Regulations 1967 made under that Act;
• the Biosecurity Act 1993;
• the Resource Management Act 1991 and plans prepared under it;
• the Pesticides Act 1979 and its replacement, the Hazardous Substances and New Organisms Act 1996;
• the Civil Aviation Act 1990;
• the Reserves Act 1977 and the Conservation Act 1987
• the Environmental Protection and Enhancement Procedures.

4.2.1 The Biosecurity Act

This Act provides MAF with the power to carry out aerial spraying to eradicate painted apple moth. In addition, MAF approved persons can declare controlled areas under s131(2), give notice of movement controls (s131(3)(a)), give notice of compulsory procedures (s131(3)(b)), and issue restricted place notices (s130).

4.2.2 The Resource Management Act

Resource consent requirements for the discharge of contaminants

Section 15 of the Resource Management Act (RMA) requires a resource consent to be obtained from a regional council to discharge any "contaminant" (this would include Btk) into water, or onto land in circumstances where it may enter water, unless the discharge is allowed by a rule in a regional plan. Section 15 also places restrictions on the discharge of contaminants into air. The requirements of section 15, together with the requirements of regional plans prepared under the RMA, mean that regional councils would normally require a resource consent to be obtained for the aerial spraying of Btk.

However, the process for obtaining a resource consent can become protracted, particularly if there are public submissions and appeals. If the process was still unresolved when the painted apple moth eggs hatched, it could jeopardise the effectiveness of an eradication programme. As an eradication programme involves considerable amounts of planning and expenditure, the Government needs to be certain that, should an eradication programme for painted apple moth prove necessary, the programme will be able to proceed. The Government has used the regulation-making powers of section 360(1)(h) of the RMA to make Regulations exempting the discharge of Btk in any spraying programme authorised under the Biosecurity Act from section 15 of the RMA.

The Biosecurity (Resource Management Act Exemption) Regulations 2002 continue the exemption granted by the Minister for Biosecurity on 18 December 2001 that exempted eradication actions from the provisions of Part 3 of the Resource Management Act 1991. They do not bypass the environmental protection provided by the Act. Rather, matters of potential environmental concern were considered by the Government at the time of drafting the Regulations instead of being considered by regional councils in the process of assessing a resource consent application. The Government is therefore, in effect, acting as the consent authority in place of the regional council.

Hazardous substances

The Regulations do not exempt the Btk spray programme from any other provisions of the RMA, including provisions in plans relating to the storage, transportation or use of hazardous substances²⁵. It should be noted that provisions on these matters may be included in regional or district plans and may or may not cover Btk, depending on the definition of "hazardous substance" adopted by the local authority in question. It is unlikely (but not inconceivable) that Btk would be included in any definitions of hazardous substances adopted by local authorities. It is also unlikely that any provisions of this type would require a resource consent to be obtained, provided that the storage, transportation and use of Btk complied with any relevant rules in any relevant plans. These matters will be checked on a case-by-case basis depending on the area in which any eradication programme takes place. Any relevant provisions in plans may help to prevent or mitigate any adverse effects arising from the storage, transportation or use of Btk.

Aircraft noise

District plans and regional coastal plans normally address any adverse effects of noise arising from activities. However, overflying aircraft are exempted from the noise control provisions of the RMA. The only noise emission controls that local authorities may set for aircraft are in relation to the use of airports²⁶.

4.2.3 The Pesticides Act

The Btk formulation Foray 48B was registered by the Pesticides Board under the Pesticides Act for use in New Zealand for the white-spotted tussock moth eradication programme. The registration process included an assessment of any adverse effects that the pesticide may have and the circumstances in which it may be safely used. The Environmental Risk Management Authority has confirmed that the formulation of Foray 48B, used in the painted apple moth programme, is covered under the transitional provisions of the Hazardous Substances and New Organisms Act 1996.

4.2.4 The Civil Aviation Act

The three main requirements of the Civil Aviation Authority under the Civil Aviation Act and related provisions are:

• approval for low level operations²⁷;
• standard operational requirements of the Civil Aviation Safety Orders, Regulations and Rules; and
• "agricultural rating" requirements for pilots.

4.2.5 The Reserves Act 1977 and the Conservation Act 1987

These Acts require that the approval of the Director-General and /or the Minister of Conservation be obtained before releasing a biological control agent onto land administered under either Act. The Department of Conservation has statutory responsibility to evaluate the likely impacts of the proposed operation on conservation values.

4.2.6 The Environmental Protection and Enhancement Procedures

The Environmental Protection and Enhancement Procedures (EPandEP) derive from a Cabinet directive, rather than legislation. The EPandEP oblige all government departments to assess the environmental impacts of their programmes and policies and compare, where possible, the environmental impacts of alternative courses of action. The preparation of this EIA is part of that process.

4.3 Public communication and information programme

MAF has implemented a public communications strategy as part of the eradication programme. The aim of the strategy is to provide the public with information on the need for the eradication programme, the effects of Btk, and steps that people can take to access practical support services if they have concerns about the effect of the programme on their health or the health of their families.

The communications strategy includes press releases, advertising, publications, direct mail, specialist meetings for the public, information targeted at general practitioners and education providers, surveys to monitor public opinion, presentations, and an 0800 enquiries line. In addition, several advisory groups have been established to cover scientific/technical, health and community matters.

In addition to general widespread publicity, discussion has taken place with key organisations - local authorities, health authoritieseducational authorities, the police, environmental groups and business groups. Initial discussion with iwi and urban Maori have included representatives of Te Whanau o Waipareira, Ngati Whatua and Te Kawerau-a-Maki. Consultation with Te Kawerau-a-Maki is ongoing, and a memorandum of understanding is being developed with MAF.

Managing an exotic pest or disease incursion under the provisions of the Biosecurity Act does not allow for community "consultation" in the generally accepted definition of that word. However, a communications strategy has provided opportunities for local public engagement over some operational aspects of the eradication programme that may be undertaken.

The availability of information, an ability to access practical support and the opportunity to discuss concerns should help to reduce levels of public anxiety about the spraying programme (as identified in Section 3.12).

4.4 Contingency plan

MAF has prepared a contingency plan to address any emergency situations that may arise during the use, transportation (aerial and ground) or storage of Btk. The plan has two aims:

_ reducing the potential for any unplanned spills or other accidents involving Btk to occur; and

_ in the event of a spill or accident, preventing, minimising or cleaning up any adverse effects.

The plan will include information on responsibilities and actions in the event of an emergency.

4.5 Storing and transporting Btk

It is likely that the Foray 48B Btk formulation will be imported, stored and transported in the form of 1000 litre bulk containers or 200 litre drums, appropriately sealed and secured. One of the risks identified in Section 3.11 of this EIA is the possible adverse effects of a spill of Btk formulation, particularly if Btk is able to enter waterways. Another concern is that the stored Btk does not become contaminated, either deliberately, as a result of sabotage, or accidentally.

Storage

The manufacturer's instructions for Foray 48B state that it is to be stored in a cool, dry place²⁸, and that containers should be kept closed when not in use.

Prior to and during the programme, Btk will be stored at a single site selected and designed for its:

• security from human interference (the site has 24-hour security);
• ability to prevent any spills from entering the environment (e.g., by way of barriers or moats);
• location in relation to potentially incompatible land uses (e.g., schools, sensitive ecosystems);
• vicinity to transport routes and loading points for aircraft; and
• compliance with any relevant provisions in regional or district plans.

Transportation

As Btk is not infectious or otherwise hazardous to humans or animals, it is not covered by any requirements relating to the transportation of hazardous substances²⁹ . Btk is not included in either the alphabetical listing of hazardous substances or the listing by UN number appended to New Zealand Standard 5433:1988 (the Code of Practice for the Transport of Hazardous Substances on Land). Nevertheless, the transportation of Btk prior to and during the eradication programme will be consistent with the Hazardous Substances and New Organisms Act 1996 and follow the general principles for transporting hazardous loads, that is:

• Btk containers will be segregated (i.e., they will not be carried with any dangerous substances or foodstuffs); and
• the load will be properly labelled and appropriate documentation relating to Btk will be carried.

4.6 Safeguards for people working with Btk

The Health and Safety in Employment Act 1992 places a general obligation on employers to provide a safe working environment for employees. For the use of pesticides, this responsibility is normally fulfilled by following the manufacturer's instructions regarding safe handling of the product. The occupational health precautions listed on the Foray 48B label are to avoid skin and eye contact, and to wash hands and exposed skin before eating and upon completion.

Section 3.8 of the EIA identified that people working with Btk may experience some adverse health effects which are likely to be irritant and transient in nature. These effects will be reduced by:

• ensuring that all people working on the programme are fully trained in the safe use of Btk;
• ensuring that all equipment used during the programme is properly calibrated and maintained;
• providing workers with appropriate protective equipment and ensuring that it is worn; and
• following the manufacturer's instructions with regard to handling and applying Btk.

4.7 Safeguards relating to the spraying operation

Potential concerns relating to the spray operation itself include:

• ensuring that each application is effective so that a minimum number of spray treatments is required;
• minimising off-target spray drift;
• accurately identifying the area to be sprayed; and
• minimising noise associated with the operation.

Maximum efficacy of each spray application will be assured by:

• using dose rates which are high enough to kill the larvae;
• timing the applications;
• spraying only during favourable weather conditions;
• using well-maintained equipment and trained applicators; and
• using appropriate technology to ensure adequate spray coverage.

Spray drift will be managed by:

• selecting nozzle sizes and calibrating equipment to achieve the recommended droplet size and spray swath path; and
• spraying only when weather conditions are favourable.

All aircraft will follow pre-determined flight transects using DGPS for guidance and will be required to conduct spray delivery calibration flights before operating over a target area.

Temporarily high local noise levels are an unavoidable effect of the spray programme. However, noise effects can be minimised by ensuring that pilots take standard flying precautions to minimise noise nuisance.

4.8 Disposal of surplus Btk

As far as possible, the Btk imported for an eradication programme will be used for the purpose for which it was intended or a similar approved purpose. The Btk containers and any remaining Btk formulation will be disposed of according to the manufacturer's instructions and any relevant local authority requirements. Any Btk containers that are recyclable must be decontaminated and the container label states that they should be triple rinsed and burnt, if circumstances permit, or otherwise buried in a landfill.

4.9 Safeguards for sensitive environments

Potentially sensitive receiving environments identified in Section 3 above include water supply areas, hospitals, schools, marae, businesses involving butterfly rearing or noise-sensitive animals and biologically sensitive areas (e.g. areas with rare insect populations). Hospitals, schools, marae and potentially sensitive businesses will be among those contacted as part of the communications strategy outlined in Section 4.3.

With regard to water catchments and water supply reservoirs, should any area for which spraying is planned include or be adjacent to these areas, the MAF will liaise closely with local health authorities and water supply authorities to determine the most appropriate means of eradicating painted apple moth from the water supply area.

4.10 Monitoring the environmental effects of the spray programme

MAF, in consultation with other relevant agencies including the Ministry of Health and the Department of Conservation, will co-ordinate the design and implementation of an environmental monitoring programme for Btk. The application of Btk to eradicate painted apple moth represents an opportunity to gather information specific to New Zealand about the environmental effects of Btk. Environmental factors can be monitored before, during and after the spray programme or alternatively, treated and non-treated areas can be compared. The advantages of a monitoring programme are:

• it helps to identify any actual adverse effects arising from the spray programme and to determine whether any remedial action is required;
• it increases public confidence that the potential environmental and health consequences of the programme are being addressed;
• it provides information should further spray programmes for painted apple moth be necessary; and
• it provides information should gypsy moth or any other exotic Lepidoptera pests ever establish in New Zealand and require eradication.

The monitoring programme should focus on assessing impacts on:

• human health, including physical and psychosocial effects; and
• non-target Lepidoptera species.

Secondary effects will be assessed if they prove necessary, following the work being undertaken by Landcare, it may include:

• possible effects on carp and native fish populations; and
• possible effects on native bird species with high proportions of Lepidoptera in their diets.

The monitoring programme will be based on overseas monitoring programmes (e.g., the surveys of hospitals and GPs carried out by Noble et al. in Vancouver in 1992) and will involve a number of agencies, including universities.

5. Comparison between the proposed means of eradication and alternative options for responding to painted apple moth

5.1 Introduction

This section of the EIA considers alternative options for responding to painted apple moth in New Zealand, and compares these options with the proposed Btk spray programme. The main options are to:

• do nothing (i.e., allow the painted apple moth to spread and establish in New Zealand if it is able to);
• use another insecticide to eradicate painted apple moth (the chemical Decis or the bioactive Spinosad are the main alternatives);
• eradicate the eggs by mechanical or chemical means;
• use biological control to reduce (rather than eradicate) painted apple moth populations³⁰; or
• use other means to reduce painted apple moth populations, such as mass trapping, mating disruption, or sterile insect release.

5.2 What may happen if no action is taken to eradicate the painted apple moth?

It is difficult to predict with any certainty what may happen if painted apple moth were to spread and establish in New Zealand. MAF conservatively estimate the potential (present net value) costs of $58 million to $356 million over the next twenty years to plantation forestry, private and public amenity plantings if painted apple moth becomes established (Anon. 2001b). Additional impacts on horticulture, watershed conservation, human health and trade are uncertain. Information is being gathered on life-cycle and feeding preference.

5.2.1 How well could painted apple moth spread and establish?

The painted apple moth is likely to disperse well in New Zealand because:

• young caterpillars can disperse by "ballooning" on silken threads; and
• plant material and inanimate objects (vehicles, garden furniture etc.) carrying larvae, egg masses or cocoons may be transported out of the infected area.
• males fly to mate.

There appear to be no obvious barriers to painted apple moth establishing throughout New Zealand. Its life cycle is influenced by standard factors such as photoperiod, temperature and food availability, but none of these should be limiting in New Zealand.

The absence of a number of natural parasitoids and predators of the painted apple moth in New Zealand should allow populations (and therefore damage) to be greater here than in its native range³¹. Competition with other species is very rarely a limiting factor for defoliating caterpillars. Their main source of competition is themselves when numbers are very high. All these factors suggest that painted apple moth could establish well in New Zealand.

5.2.2 Which plants could painted apple moth feed on?

Painted apple moth is polyphagous and the caterpillars and adults feed on a wide range of plants (see the Operational Plan, Appendix 1, Anon. 2001b). It is likely that the plant host range for painted apple moth in New Zealand will be very wide. Painted apple moth has been reported feeding on more than 50 plant species (in 24 families) in Australia and has already been reported from 26 plant species in New Zealand. This includes three native species, kowhai, mountain ribbonwood and karaka. Extensive feeding trials are currently being carried out by Forest Research to get a better idea of the painted apple moth's potential host range.

5.2.3 What impacts could painted apple moth have in New Zealand?

At this stage, the best available information suggests that painted apple moth is likely to be a significant pest in New Zealand. The potential impacts of painted apple moth include:

• damage to amenity trees, bushes, horticulture plants and other plants, including urban trees and home gardens;
• reduction in the ability of forests to function as a carbon sink (part of New Zealand's strategy to mitigate the effects of climate change);
• defoliation or mortality of indigenous vegetation, with various possible consequences including changes in the biological composition of forests, erosion of water catchments, downstream flooding, loss of recreational and amenity values, and loss of habitat for indigenous species;
• costs of on-going control programmes; and
• possible adverse effects on tourism and trade.

5.3 What chemical insecticides could be used?

In New Zealand, control of the insect has been attempted using an organophosphate insecticide Chlorpyrifos (Dursban), which was applied from the ground to host trees in the infested properties, as well as surfaces of buildings and other equipment or containers. Chlorpyrifos,is a broad spectrum insecticide used on a wide variety of crops for the control of locusts, and is also present in some cattle dips for the control of ticks and lice. Chlorpyrifos is very toxic to humans. Chlorpyrifos toxicity is considerably greater if administered orally compared to dermal. Inhalation exposure to high concentration may cause upper respiratory irritation, central nervous system depression headache, dizziness, irregular heartbeats, incoordination, blurred vision and convulsions. Eye contact may cause pain and moderate irritation. The health concerns about chlorpyrifos would restrict its use in some situations.

5.3.1 Dimilin

What is Dimilin?

Dimilin (diflubenzuron) is a chemical insecticide, which has been used to control gypsy moth in North America for a number of years. It intervenes in the formation of chitin (a substance found in the exoskeleton of insects) and thereby interferes with the moulting process of some immature insects. Of the available chemical insecticides, it is considered to be the best option for controlling painted apple moth because of its extensive use in North America, its relatively narrow range of non-target organisms, and its low mammalian toxicity compared with other chemical insecticides.

Health effects

No human health effects are likely from exposure to Dimilin at the dose rates used in eradication programmes. However, at very high exposures, increases in methaemoglobin (an abnormal blood pigment that reduces the oxygen carrying capacity of the blood) might be detectable. This effect may be additive if other compounds which reduce the oxygen carrying capacity of blood are present (cigarette smoke, other smoke, carbon monoxide, nitrates in air or water) (USDA 1995). A conservative estimate of cancer risk from exposure to Dimilin or its breakdown products is less than one in one million over a lifetime (USDA 1995).

Environmental effects

Dimilin persists on vegetation throughout the growing season and may remain on leaf litter at least one year after spraying. Non-target organisms affected by Dimilin (even at low doses) include other caterpillars, other leaf and litter-eating immature arthropods, parasitic wasps, some beetles, spiders, sawflies, aquatic insects, bottom-dwelling crustaceans and immature free-floating crustaceans. At higher doses, more species are affected, especially aquatic organisms (USDA 1995). Vertebrates, adult beetles, earthworms, bees and molluscs do not appear to be affected. Neither does Dimilin have any toxic effect on plants (USDA 1995).

Advantages and disadvantages of Dimilin compared with Btk

The advantages of Dimilin (diflubenzuron) are:

• it is persistent on foliage for much longer than Btk, so only one application is necessary;
• its effectiveness is not restricted to the early stages of caterpillar development. Dimilin therefore has a wider application window than Btk, and the eradication programme would be at less risk of failure because of bad weather conditions; and
• it requires only a few applications so the cost of eradication is less than it would be using Btk.

The disadvantages of Dimilin are:

• it could have an adverse effect on some marine life such as freshwater crayfish;
• it affects a wider range of invertebrates than Btk, and is therefore less desirable environmentally;
• it has some documented adverse effects on human health; and
• it is a chemical insecticide and is therefore likely to create greater public resistance to spraying in urban areas than would be created by spraying a naturally occurring bacterium such as Btk.

5.4 How does the use of other "biological" insecticides compare with the use of Btk?

Although no specific information is available about the susceptibility of painted apple moth to eradication using insecticide sprays, there is no doubt that chemical sprays could be an effective means of eradication. Chemical sprays have been used successfully on the Lymantriidae gypsy moth populations in North America, and another related species, Orygia pseudotsugata, can be well controlled with chemical sprays (Anon 1980, Neisess et al. 1976). However, when comparing Btk with other agents, effectiveness is just one criterion and emphasis is also placed on environmental and health effects.

5.4.1. Deltamethrin (Decis Forte)

What is deltamethrin?

Deltamethrin is a synthetic pyrethroid (product name Decis Forte) which has been used for some of the ground spraying against painted apple moth. It is a third generation synthetic pyrethroid insecticide approved for use in New Zealand and in many other countries including USA, UK, Europe and Australia. This insecticide has been widely used by horticulturalists (particularly on vegetable crops) for about fifteen years. It is commonly used to treat a range of vegetable crops, as well as ornamentals, for caterpillars and other insect pests. It is also a component in certain animal remedies, such as pour-ons used to treat sheep for lice and ticks, and as a flea control.

Health and environmental impacts of deltamethrin

Information on the IPCS international programme on chemical safety, Health and Safety Guide No. 30 on Deltamethrin (WHO, 1989) show Deltamethrin has a high LD₅₀ against rats (>5000mg/kg). The substance is very toxic to aquatic organisms in the laboratory. The 96-h LC₅₀ for fish ranges between 0.4 and 2.0 µg/litre, while the 48-h LC₅₀ for Daphnia is 5µg/litre. However, field use and extensive field studies in experimental ponds have shown that this high potential toxicity is not realized. Some kills of aquatic invertebrates occur in the field, but usually there is rapid compensation It has low toxicity to birds, but can kill honey bees on direct exposure. Persistence is moderate, with survival of activity around 8 weeks in sand at 28^oC.

Deltamethrin can induce skin sensations in exposed workers, but most symptoms are transient and disappear within 7 days. Three non-fatal cases of deltamethrin poisoning after the ingestion of several grams of the product have been described.

Advantages and disadvantages of deltamethrin compared with Btk

The advantages of deltamethrin are:

• more persistent and can act on contact, rather than needing to be ingested, which means can work on inorganic surfaces (larvae can be found on walls etc.)
• probably cheaper
• not a living organism, so easier to use

The disadvantages are:

• has some toxicity to non-target organisms in the laboratory, especially aquatic organisms
• some health risks to humans would rule out use in aerial spraying or non-specific application.

5.4.2 Spinosad

What is Spinosad?

Spinosad is a naturally derived fermentation product of the actinomycete Saccharopolyspora spinosa. It is used for control of chewing insect pests on a range of crops. There are a number of products based on spinosyns available from Dow Agrosciences. Tracer NaturalyteTM, Success NaturalyteTM, SpinTorTM Naturalyte and ConserveTM SC are the four main products currently available commercially; these are formulated for different agricultural, ornamental and forestry applications against various pest insects. Spinosad works by both direct contact and ingestion by insects. Spinosad is generally most active against adults and larvae, with some activity against eggs of selected species.

Health and environmental impacts of Spinosad

The environmental and health impacts of spinosad were reviewed by O'Callaghan and Glare (2001). Spinosad is generally reported as non-phytotoxic to plants. Non-target studies on micro-organisms and many small invertebrates are lacking with most studies available on non-target effects focus on beneficial insects in economically important crops. In general, spinosad products have few impacts on beneficials, but non-target safety has perhaps been overstated in some reports and product information. Direct toxicity has been found to bees and certain parasites.

Very limited information is available on the effects of spinosad on fish and other aquatic species. Ratings of "slightly to moderately toxic" were assigned to spinosad in studies against fish and Daphnia (an aquatic invertebrate) in the USA. Mammalian toxicity data are only available through the USA Environmental Protection Agency (EPA) evaluations. The EPA assessed spinosad at the lowest caution level for mammalian toxicity. Spinosad was also assessed as "practically non-toxic" to birds. The half-life of spinosad degraded by soil photolysis is 9-15 days, less than 1 day for aqueous photolysis and 1.6-16 days for leaf surface photolysis.

Advantages and disadvantages of Spinosad compared with Btk

The advantages of Spinosad are:

• Despite no tests on efficacy against painted apple moth, lepidopteran larvae are among the main targets of spinosad and are highly susceptible.
• Based on the data supplied to the EPA, spinosad has been allocated very low mammalian toxicity ratings.
• Small amounts need for toxicity.
• Not a living organism.

The disadvantages are:

• The main disadvantage with spinosad is that few independent studies on environmental and mammalian safety have been published, so no long-term ecological or health studies have been completed.

Therefore, it would be difficult to recommend for use against an urban-located pest.

5.6 What are the advantages and disadvantages of Btk compared with alternative approaches?

The advantages of Btk in comparison with the alternative approaches discussed above are:

• Btk has a history of successful use in the US for 30 years, for many years in Canada, and latterly also in Europe;
• Btk was used successfully to eradicate white-spotted tussock moth in Auckland in 1996/97;
• Btk is non-toxic to mammals, birds, fish, and most invertebrates other than caterpillars;
• New Zealand currently has the technology and experience to organise and apply the Btk formulation for painted apple moth;
• Btk is effective against all stages of painted apple moth larvae;.

The disadvantages of Btk are:

• Btk will require multiple applications (between three and five) at regular intervals to cover the period when susceptible painted apple moth caterpillars will be present;
• Btk will need to be imported from overseas (as will most possibilities); and
• Btk is removed from vegetation by rain, and given unfavourable climatic conditions (consistent high wind and/or rain) the programme may not succeed in eradicating the moth. (However this is also true of other eradication techniques because they rely on aerial spraying.)

5.5 What other means to assist eradication or control may be available?

Aerial and ground spraying with Btk or another insecticide are two of the most feasible approaches by which the painted apple moth population could be eradicated. Of these two methods, Btk is the more environmentally acceptable. Pheromone-based techniques, such as mass trapping or lure-and-infect, require a highly attractive synthetic pheromone and, while research on this is continuing, none was available at the time of writing this report.

The remaining options discussed in this section relate to controlling the painted apple moth populations in an effort to reduce its impact. Most of these options have been developed for controlling other Lymantriid pests such as gypsy moth and may or may not be transferable to painted apple moth.

Methods designed to control painted apple moth would only be considered if eradication is not the Government's preferred option, or if eradication failed and the moth became established in New Zealand.

5.5.1 Biological control agents

No biocontrol agents to reduce populations of painted apple moth have currently been tested, either in New Zealand or overseas. AgResearch, HortResearch, Forest Research and Otago University are currently investigating biological control options.

Parasites and predators

If painted apple moth is not eradicated from New Zealand, a certain amount of parasitism and predation will occur by indigenous and naturalised species. This has been found by the team surveying populations, with a number of parasitised individuals collected. A New Zealand Pest Risk Assessment for Asian Gypsy Moth (Cowley et al. 1993) assumed a 10 percent rate of parasitism and predation under New Zealand conditions and five percent mortality from natural fungal, bacterial, and virus diseases. Similar estimates for painted apple moth are not available, but parasitism rates may be higher at some times of the year. There may also be potential for heavy predation by birds if there is no other food available (based on a study by Whellan et al. 1989 on gypsy moth predation).

In the US, parasites have been introduced to control gypsy moth, but researchers do not believe that they play a major role in regulating populations. Similarly, predation has been found to help maintain sparse population numbers, but does not affect population densities if an outbreak occurs (USDA 1995). There are no parasites or predators currently known that could be introduced to control a New Zealand painted apple moth population and maintain it at a non-damaging level.

Beauveria bassiana

The fungus Beauveria bassiana is a common insect-pathogenic fungus found throughout the world. It has a host list of over 600 insects, although individual strains are more restricted in their host preferences. Since painted apple moth was discovered in New Zealand, several individual larvae have been collected infected with B. bassiana (Flynn and Glare, unpubl. data). The fungus has previously been developed as a commercially available biopesticide for control of aphids, thrips and beetles on crops (in the USA, Columbia, China and Europe). While the fungus can kill painted apple moth larvae, the strains present in New Zealand are unlikely to be the most appropriate for control, as no Lymantriids have established in New Zealand previously. B. bassiana is unlikely to be acceptable as an aerially applied biopesticide due to non-target impacts on invertebrates, but may be a useful control agent if selected strains can be obtained from overseas.

Viruses

Another biocontrol option is the use of naturally occurring insect viruses. A nuclear polyhedrosis virus was isolated from T. anartoides by Teakle (1973) in Australia, but little is known about the virus and few baculovirus products have ever been sold commercially. None have been successfully used in eradication attempts, except for gypsy moth where a virus was used in conjunction with the bacterium Bacillus thuringiensis. In North America, gypsy moth control programmes make use of the Lymantria dispar Nuclear Polyhedrosis Virus (LdNPV), which affects only gypsy moth (USDA 1995). The Canadian Forest Service has used another virus, the Orgyia Nuclear Polyhedrosis Virus (Orgyia NPV) to control other moths in the genus Orgyia (Walsh et al. 1999). The advantages of viruses are that they are host specific and so do not affect other caterpillars. They provide good population control when moth population numbers are very high, but are not successful in eradicating moth populations (Bain 1996 - pers. comm to N Gibbs). Other recorded disadvantages of LdNPV are that it is expensive and is available only in limited supply. The Orgyia NPV is said to infect a number of species in the Orgyia genus and has achieved good control of some members of the genus, but there is no information specific to its effect on painted apple moth.

5.5.2 Mass trapping

Mass trapping method involves setting up large numbers of moth traps in the treatment area. The traps use a pheromone to attract male moths of the pest species. The moths are killed either on a sticky strip or on a strip impregnated with an insecticide in the trap. Male moths are therefore prevented from mating with females and population reduction results. Mass trapping is not seen as an eradication method, but may be used in conjunction with other control methods. It should be noted that this method is not possible until a synthetic pheromone can be developed.

The disadvantages of this method for controlling painted apple moth are:

• a pheromone for painted apple moth is not currently available;
• there may be some human health risks associated with people tampering with insecticide-impregnated strips in the traps (USDA 1995);
• non-target insects which inadvertently enter the traps may be killed (USDA 1995); and
• traps must be extremely densely located in the target area.

5.5.3 Mating disruption

Mating disruption is another method which relies on the availability of a pheromone capable of attracting male moths of the pest species. The method, which has been used on gypsy moth in North America, involves distributing pheromone flakes or beads by aerial application. This has the effect of confusing the male moths and preventing them from locating the females. Many females therefore remain unfertilised.

There is no information on mating disruption specific to the painted apple moth, as a specific pheromone for the species has not been isolated. However, the method may be promising for painted apple moth control, as it has been found to successfully reduce gypsy moth populations in treated areas (Mastro 1994) and good results have also been shown on the related species O. pseudotsugata (Hulme and Gray 1994; Sower et al. 1983; 1990). It should be noted that this method is not possible until a synthetic pheromone can be developed.

5.5.4 Sterile insect techniques

Sterile insect techniques involve the sterilisation by radiation of large numbers of reared moths of the pest species. The sterile insects are then released into the environment and mate with fertile adults, producing infertile eggs. The effect, in theory, is population reduction and eventual elimination. In small field trials with gypsy moth, the technique produced a significant decline in the hatching rate of eggs (Maksimovic 1972). In practice, the logistics of sterile insect programmes are immense, and operational problems can severely hamper their effectiveness (California Department of Food and Agriculture 1992).

HortResearch are currently investigating sterilising techniques with painted apple moth.

6. Consultation

6.1 Public consultation

It is usual during the preparation of an EIA for those who may be directly affected by the proposed activity (e.g. community groups, local residents), to be consulted directly. However, in this case, the opportunity to consult widely was constrained by the provisions of the Biosecurity Act. Local public consultation was also constrained because an EIA applies to the whole country whereas, for any one-spray programme, only a small part of the country would be affected. For these reasons, consultation during the preparation of the EIA has been confined largely to those agencies and individuals who would be able to provide specific technical comments on the draft EIA. Details of how local communities will be provided with information and liaised with on any eradication programme are set out in Section 4.3 of the EIA and available from MAF.

6.2 Agencies consulted

The Department of Conservation was consulted in the preparation of this document, and comments made by the Department on the draft have been incorporated.

6.3 Environmental groups consulted

Copies of the draft Assessment were sent to various environmental groups operating in the proposed spray zone. These included the Royal Forest and Bird Protection Society, Friends of the Whau Inc, and the Waitakere Ranges Protection Society. No submissions on the draft were received from any of the groups.

7. References

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Glossary

actinomycete
a type of soil microorganism

active ingredient
in relation to an agrichemical, is the ingredient which has a toxic effect on the target organisms.

ADI
abbreviation for Acceptable Daily Intake - the level of exposure to a toxic substance which is considered safe (set, for example, by the World Health Organisation).

agrichemical
any substance, whether inorganic or organic, manufactured or naturally occurring, modified or in its original state, that is used in any agriculture, horticulture, forestry, management of public amenity areas, or related activity, to eradicate, modify, or control flora or fauna.

arthropod
a large group of invertebrate animals with a segmented body and jointed limbs (e.g., insect, spider, crustacean).

Bacillus thuringiensis
scientific name of a naturally occurring bacterium which is used to control populations of insect pests.

bioaccumulation
accumulation within the tissues of living organisms.

biocontrol
the managed use of an organism's natural parasites, diseases and predators to control pest populations of the organism.

BIU
abbreviation for Billions of International Units - the standard measurement for Btk dose rates. It is based on Btk activity against the cabbage looper larvae.

Bt abbreviation for Bacillus thuringiensis.

Btk
abbreviation for Bacillus thuringiensis kurstaki, a variety of the bacterium B. thuringiensis.

chitin
a strong, light-weight material which is a component of the exoskeleton of insects.

colony-forming units a measure of exposure to biological insecticides. A colony-forming unit may consist of one or more spores.

crustacean
a member of a group of hard-shelled, mainly aquatic, animals including crabs, crayfish, shrimps etc.

DGPS
abbreviation for Digital Global Positioning System. A satellite-based positioning or navigation system which provides extremely accurate measurements of the three-dimensional position, velocity and time of the receiver.

diflubenzuron a chemical insecticide.

Dimilin
a chemical insecticide (active ingredient diflubenzuron).

Dipel
a Btk formulation.

disparlure
a pheromone which has been isolated to attract male gypsy moths.

EIA
abbreviation for Environmental Impact Assessment - the process of evaluating the potential environmental effects of a proposal. This process may include preparing a written report.

endospore
a type of resting cell which develops within a bacterial vegetative cell under certain conditions. Endospores are extremely resistant to adverse environmental conditions.

endotoxin
a component of the walls of bacteria that is toxic to ainvertebrates.

epidemiology
the branch of medicine concerned with the control of epidemics.

epizootic
occurrence of a disease in animals that is widely prevalent and spreads rapidly.

exoskeleton
the tough external skeleton of an insect.

exotoxin
a toxin that is secreted by a living organism.

Foray 48B
an agrichemical formulation with Btk as the active ingredient.

half life
the time taken for a substance to loose half of its activity (e.g., radioactivity for a radioactive substance, insecticidal activity for an insecticide).

indigenous
belonging to a region, not introduced.

inert ingredient
those substances in an agrichemical formulation other than the active ingredients.

insecticide
an agrichemical which affects insects.

instar
the form an insect takes between successive moults.

invertebrate
an animal without a backbone.

iwi
tribe, people.

larva
stage in development between hatching and attaining adult form. For moths and butterflies, this stage is the caterpillar.

LD₅₀
abbreviation for lethal dose - the dose of a substance at which 50% of the test animals die in a given test period. It is a measure of acute toxicity of a substance.

LdNPV
(Lymantria dispar Nuclear Polyhedrosis Virus), a virus used to control populations of gypsy moth.

Lepidoptera
moths and butterflies.

Lymantria dispar
the scientific name for gypsy moth, a relative of the white spotted tussock moth and painted apple moth.

Lymantriidae
the scientific name for the family which includes tussock moth, gypsy moth and painted apple moth.

MAF
Ministry for Agriculture and Forestry

microorganism
group of small organisms (e.g., bacteria, virus, fungi and protozoa).

mutation
a genetic change which, when transmitted to offspring, gives rise to heritable variation.

nematode
a type of slender, unsegmented worm.

non-target organism
any living organism that is not the target of a management practice.

Orgyia pseudotsugata
the scientific name for Douglas fir tussock moth, a relative of the white-spotted tussock moth Orgyia thyellina, and the painted apple moth Teia anartoides.

Orgyia thyellina
the scientific name for the white-spotted tussock moth.

parasitoid
a parasite that lives inside an insect host.

pathogenic
disease-causing.

pH
a measure of the alkalinity or acidity of a substance. pH 1 is very acidic, pH 14 is very alkaline.

phagostimulant
a substance which encourages feeding.

pheromone
a substance secreted from an animal which influences the behaviour of other members of the species. Most commonly applied to sex attractant scents.

photoperiod
day length.

phytotoxicity
the ability of a substance to cause a toxic effect (destroying life or injuring health) on plants.

ppm
parts per million, a measure of concentration

protein crystal
in relation to Bacillus thuringiensis, is a substance produced by the bacterium at the time of sporulation. The protein crystal may contain toxins.

sporulation
spore-forming.

tangata whenua
literally, people of the land. Refers to the iwi or hapu of an area.

Teia anartoides
the scientific name for painted apple moth

Thuricide
a Btk formulation.

UV
(ultra-violet) a form of radiation just beyond the violet end of the visible spectrum.

vegetative cell
an actively growing cell (as opposed to a cell that forms spores).

Appendix 1: Threatened Lepidoptera of West Auckland

Dr Robert Hoare,

Lepidoptera systematist

Landcare Research,

Private Bag 92-170

Mt Albert, Auckland

Species listed by Patrick and Dugdale (2000) were considered by these authors to be `at risk' at a national level. Host-plants and biology are unknown unless otherwise indicated. Species known mainly from Titirangi, and not or hardly from the Waitakere Ranges are marked with an asterisk*.

Species with exposed (i.e. external-feeding) larvae (or believed likely to have exposed larvae) and which are therefore most at risk from aerial spraying of Btk are marked with a dagger _.

NEPTICULIDAE

Stigmella maoriella

This species has not been collected since it was described from Auckland in the 1850's. However, it is considered that nepticulid leaf-mines which occur very locally but sometimes commonly on Olearia furfuracea in west Auckland may belong to this species. The mines have only been found in one locality (Hawkes Bay region) outside Auckland. Listed by Patrick and Dugdale (2000).

PSYCHIDAE

(_)*Liothula sp. `transparent'

This is a recently recognized species previously confused with the Common Bagworm, L. omnivora. It has only been collected in two South Island localities (Mahana and Greymouth), on Mt Ruapehu, and in Laingholm and Titirangi. Larva is a case-maker, so may have some protection from spray.

TINEIDAE

Bascantis sirenica

This species has not been collected for more than 50 years, and has always been rare. It was recorded from the Waitakeres by G.V. Hudson.

`Matuku monster'

A very large striking tineid known from a single specimen from Matuku Reserve. At first believed to be a foreign species, it has baffled the international experts on Tineidae, so it may be an overlooked and rare endemic.

Thallostoma eurygrapha

Almost all recent specimens of this rare species are from the Waitakeres and Titirangi.

PLUTELLIDAE

*Proditrix gahniae

Almost all of the few known specimens were collected in Titirangi. Host Gahnia (cutty-grass).

OECOPHORIDAE

*Coridomorpha stella

Only 5 specimens collected in the last 50 years, the most recent in Titirangi, December 1999. Listed by Patrick and Dugdale (2000).

*Coridomorpha sp. `long palpi'

Only 4 specimens known, all from Titirangi. Listed by Patrick and Dugdale (2000).

_*Hierodoris sp. `tiger-stripes'

Only known from gardens in Titirangi, and from a single specimen collected in a tiny forest remnant at Clevedon, south Auckland. Listed by Patrick and Dugdale (2000). Suspected host is rimu.

*Hierodoris iophanes

The few recent specimens are from the Mamaku Plateau (BP) and Titirangi.

*Izatha balanophora

Very few specimens known from outside the Auckland region, and recorded from Titirangi, although not from the Waitakeres proper.

*Izatha sp. `small grey'

Only known from Omahuta Forest, Northland, and two specimens from Titirangi.

*Izatha sp. `broad pallid'

Only known from Auckland and the Mamaku Plateau area (near Rotorua). Three of the 8 known specimens were collected in Titirangi and Huia.

*Corocosma memorabilis

Very few specimens of this species are known; one was taken in Titirangi in 2000, and one in 2001.

*Trachypepla amphileuca

Usually a rare species; Titirangi is the only place where it has been collected commonly.

*Trachypepla festiva

All recent specimens are from Henderson and Titirangi.

*Trachypepla hieropis

Most of the few recent specimens are from Titirangi.

*Stathmopoda trimolybdias

Two specimens have been collected in Titirangi and one in Laingholm in recent years. Apart from one from Nelson, these are the only specimens of this rarely seen species in the NZAC.

ELACHISTIDAE

*Elachista melanura

Only known from two specimens, one collected in Hamilton in the early 1880's, the other in Titirangi in February 2000.

GELECHIIDAE

Epiphthora nivea

Only known from the Waitakere Ranges. Larva on Collospermum hastatum.

TORTRICIDAE

*Pyrgotis zygiana

A rarely collected species, recently discovered in Titirangi. Larva on Prumnopitys taxifolia (matai).

CARPOSINIDAE

*Ctenarchis cramboides

Only known from Auckland and Northland. Very rarely seen. Most specimens have been collected in Titirangi. Listed by Patrick and Dugdale (2000).

*Heterocrossa sp. `big grey'

Only known from three specimens; one from the Tararua Range, Wellington, one from the Darran Mountains, Fiordland, and one from Titirangi.

COPROMORPHIDAE

*Isonomeutis restincta

Only known from Northland, Auckland and Taupo areas; very rarely collected. The most recent specimen was taken in Titirangi, December 1999. Listed by Patrick and Dugdale (2000).

NYMPHALIDAE

_Dodonidia helmsii Forest Ringlet butterfly

A declining species, recorded very sparingly from the Waitakeres and Titirangi. Listed by Patrick and Dugdale (2000). Host-plant Gahnia spp. (cutty-grass).

GEOMETRIDAE

_*Pasiphila sp. `three-spotted'

Only known from two localities in the central North Island, from the Rodney district (one specimen) and one specimen from Titirangi. Larva probably on flowers.

_*Tatosoma alta

Titirangi appears to be a stronghold of this rarely collected species. Host-plant Phyllocladus (tanekaha, toatoa).

NOCTUIDAE

_*Bityla sericea

Very rarely seen. The only specimen from the Auckland district was collected in Titirangi in the early 1950's. Listed by Patrick and Dugdale (2000). Larva probably on Muehlenbeckia.

REFERENCE

Patrick, B.H. and Dugdale, J.S. 2000. Conservation status of the New Zealand Lepidoptera. Science for Conservation 136. 33pp. Department of Conservation.

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Footnotes

1. A study on the potential effects of the programme on rare moths in west Auckland has been undertaken by scientists at Landcare Research Ltd (Hoare, 2002).
2. No businesses involved in rearing butterflies or moths are known to be located within the painted apple moth spray area, however there is one business just outside the zone, assistance has been provided to mitigate the impacts of the spray operation.
3. Eradication involves a one-off cost rather than the ongoing costs of control and, if successful, means that there will be no ongoing adverse effects from the pest species.
4. Painted apple moth was first reported in New Zealand by Harris (1988), also Dugdale (1988) who reported that "live adults, eggs and larvae were landed at Dunedin DN in 1983".
5. The fact that Bt occurs naturally in soils has no bearing on any potential adverse effects Btk formulations may have.
6. An instar is the form an insect takes between moults.
7. Some Bt varieties such as Bacillus thuringiensis thuringiensis produces exotoxins which can be toxic to mammals and are potentially mutagenic (BC MOH 1992).
8. Ministry of Health (NZ) pers. comm. (comment on a draft EIA, 17 June 1996).
9. In 1992, Foray 48B samples were tested as part of a study on the health effects of Foray 48B, and no contamination was found (Noble et al 1992). Each consignment of Foray 48B received for use in the painted apple moth programme is being tested for contamination prior to use.
10. This assumes that painted apple moth is as susceptible to Btk as its relatives, which has been shown in bioassays (M. Kay et al., unpubl. data).
11. Spraying programmes in the 1980s used the formulations Thuricide or Dipel applied at rates of 30 BIU/ha (see footnote 12). In the 1990s, Foray 48B at rates of 40 BIU/ha has been used. Areas treated by aerial spraying ranged from 10 ha to 18 813 ha (Vancouver in 1992), and ground spraying was also used. Multiple applications (three times a year) were frequently used. Efficacy monitoring involved intensive pheromone trapping.
12. BIU/ha is an abbreviation for Billions of International Units per hectare. International Units are a commonly recognised way of measuring Btk dose rates.
13. Van Frankenhuyzen et al. 1993. Canadian Entomologist 125, quoted in STOP 1995.
14. In this and the following discussions of the persistence of Btk in the environment, please note the distinction between persistence (i.e., survival in the environment, usually in the form of an endospore), toxicity (from endotoxin survival) and pathogenicity (multiplication in an organism so as to cause a disease). Persistence does not necessarily imply any adverse effect.
15. However, if Btk was to be sprayed in an area where attempts were being made to establish a lepidopteran biocontrol agent, it would have to be assured either, that the control organism could be reintroduced once Btk was no longer present or that the benefits of spraying outweighed the costs of not being able to reintroduce the agent.
16. The "half life" of a substance is the time taken to lose 50% of its activity.
17. Another reported study found that snails were affected by low concentrations of the Bt formulation Thuricide. A significant decrease in egg laying activity, size of egg masses and egg hatching was observed (Osman et al 1991, quoted in STOP 1995).
18. The length of time taken for recolonisation would depend, to an extent, on the size of the area sprayed (a larger area would take longer to recolonise).
19. Department of Conservation, pers. comm. (comment on the draft Btk against tussock moth EIA, 21 June 1996)
20. 300m is the likely range of off-target spray drift that may have some effect (e.g., insecticidal effect or visual effect). However, with sophisticated monitoring techniques, minute quantities of spray drift may be detected at distances considerably further from the target area.
21. A child's or elderly person's auditory reflex is unable to provide the level of protection afforded to other adults.
22. Philip Dickinson, noise engineer, Ministry of Health, pers. comm. (comment on draft Btk against tussock moth EIA, 17 June 1996).
23. Ministry of Health (NZ) 1996, pers. comm. (comment on draft Btk against tussock moth EIA, 17 June 1996).
24. There are some anecdotal reports of effects of this type from spray programmes in Washington State (Washington State Department of Health Report of Health Surveillance Activities, Asian Gypsy Moth Control Program, March 1993. In STOP 1995).
25. The RMA gives regional councils responsibility for "the control of the use of land for the purpose of the prevention or mitigation of any adverse effects of the storage, use, disposal or transportation of hazardous substances" (s.30). Territorial authorities have a similar responsibility under s.31.
26. See Sections 9(8) and 12(5) of the RMA. "Aircraft" includes fixed wing aircraft and helicopters.
27. Under Civil Aviation Rules the Director of the Civil Aviation Authority has set conditions and limitations on the aerial operation for the painted apple moth.
28. Optimum storage temperature is 5^oC.
29. These requirements arise from the Transport Act 1962, New Zealand Standard 5433:1988, traffic regulations and various gazette notices.
30. The use of the term "biological control" in this section refers to methods of biological control other than the use of Btk (which can be classified as a biocontrol agent itself).
31. This situation is usual with introduced insects, providing other factors are not limiting.

Page last updated: 7 August 2008