Gypsy moth levy unchanged in 2008-09

Figure 1: Asian gypsy moth adult female (left)
and male
Photo: Melody Keena, United States Department of
Agriculture Forest Service

This year (2008-09), the gypsy moth levy placed on all shipping containers and used cars imported into New Zealand will again remain unchanged at 65 cents per unit.

The levy covers the annual cost of the gypsy moth surveillance programme, and tendering the work has ensured that the programme maintains a high level of efficiency. As a result, the levy has continued unchanged since its introduction.

Gypsy moth (Lymantria dispar) is a major threat to the New Zealand environment, and has been the target of specialist surveillance since 1992, when ships from Eastern Russia were identified as being capable of transporting Asian gypsy moth egg masses to our shores. Asian gypsy moth could enter New Zealand from any temperate East Asian country, including China, Japan, the Russian Federation and South Korea.

A recent review of the available evidence¹ suggests that the pathway most likely to result in entry and establishment of Asian gypsy moth is used vehicles (specifically from Japan). While current measures do reduce the likelihood of entry and establishment, they do not reduce it to a negligible level. The next most likely pathway is sea containers.

In 2005, the surveillance programme was revamped to increase the probability of detecting any stray moths. The most significant improvement was targeting high-risk pathways for gypsy moth introduction into New Zealand. For example, transitional facilities process the approximately 500,000 imported sea containers arriving in New Zealand annually. Along with the main population centres, they represent some of the most likely areas for an incursion. A grid-based trapping system is now used to allow a large area to be covered with a relatively small number of traps.

Figure 2: Gypsy moth egg mass from
car imported from Japan

The programme is based on the placement nationwide of around 1,600 pheromone-baited traps. These are checked fortnightly from November through to April. Any suspect moth captured in a trap is sent to Scion entomologists for identification. All moths forwarded to Scion this season were already known from New Zealand; no gypsy moths were found.

In 2003, a gypsy moth was trapped in Hamilton as part of the surveillance programme. This detection resulted in a successful eradication programme, highlighting the value of the early warning trapping system.

• Paul Stevens, Senior Adviser (Plants Surveillance), Post Border Directorate, MAF Biosecurity New Zealand, paul.stevens@maf.govt.nz

¹ Pest risk analysis for six moth species: lessons for the biosecurity system on managing hitchhiker organisms. See www.biosecurity.govt.nz/strategy-and-consultation/consultation/moths-risk-analysis

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