Frequently asked questions about aerial treatment operations

Aerial treatment using Foray 48B is one of the ways that MAF is combatting the gypsy moth in Hamilton. Other methods MAF is using include intensive pheromone trapping, ground searching and treatment and vegetation control. This combination is considered the best way to successfully eradicate gypsy moth and the only way to treat hard to reach foliage throughout the risk area.

The combination of aerial treatments using Foray 48B and intensive pheromone trapping were used successfully to eradicate white spotted tussock moth from eastern suburbs of Auckland in 1996 and 1997. Aerial operations are proving effective in the treatment of painted apple moth in western suburbs of Auckland. Over the past 18 months, there has been a dramatic drop in the pest population.

The programme outlined below has been prepared by a team of experts, based on information from the male moth found in March and knowledge of how the pest behaves overseas.

There is always a chance that gypsy moth will behave differently in the New Zealand environment. It may be necessary to change some of the details set out below if MAF discovers new information about the feeding and lifecycle of this pest. You will be notified of any significant changes through the media and advertisements.

thumbnail of aerial operation and vegetation control zoneYou will also be notified if any new finds outside the current aerial operation area shaded in yellow in the map require new areas to be treated as part of this programme or in the current programme or in the future.

On what days will the aerial operation go ahead?

  • The first planned aerial treatment will be in the week starting 8 October 2003.
  • Aerial operations are effective against the gypsy moth only during spring when the pest is in its catepillar life stage. Foray 48B will not kill the pest when it is in its other life stages.
  • Further aerial operations are planned for approximately every seven days during spring.
  • The gaps between aerial treatments may be shorter or longer than seven days depending on delays caused by the weather.
  • There will be a minimum of 5 days between each individual treatment.
  • There will be a maximum of 8 treatments during spring.
  • Based on current understanding of the caterpillar gypsy moth life cycle, treatment is likely to finish early in December. The treatment period, but not the number of treatments, may be extended if the pest is still in the caterpillar stage at that time.

What time do aerial treatments start and finish?

  • Treatments start as soon after daylight as the weather permits.
  • This can be as early as 5.00am in spring.
  • There will be no spraying on treatment days at those times children are most likely to be travelling to and from school and eaing their lunch. These times will be discussed with local schools and will be announced through the media and advertisements.
  • We cannot tell you the exact time the aircraft will be in your area.
  • If weather conditions are ideal, treatments should be completed in half a day.
  • You can find out whether aerial operations have finished for the day by listening to radio updates.
  • If you are registered for text message or email updates, you will automatically receive notification that treatment has finished.
  • The website and recorded message on 0800 809 966 will also be updated when the current operation is completed.

Why does aerial treatment sometimes not happen on the planned day?

  • The weather can cause planned operations to be delayed.
  • The following weather conditions can affect the treatment schedule:
    • Winds above which it is recommended we spray.
    • Temperature.
    • Rain and humidity.
    • Fog, which affects visibility.
    • Wet vegetation.
  • There must be a minimum of 5 days between treatments, so if the weather delays an operation for more than three days the next treatment will also be delayed.

How do I find out if a treatment is going ahead on a particular day?

  • Email and Text Messages: we can automatically send you email or text updates. All you need to do is register on-line or free phone 0800 809 966. If you are registered, we will send you messages on a treatment day before an operation starts and as sooon as it is finished. We will also let you know if a treatment is delayed.
  • Radio - listen to; Classic Hits (98.6 FM), Newstalk ZB (1296 AM and 97 FM) or ZM 89.8 (89.8 FM) about 2 minutes before the hour between 5.00am and 7.00pm during aerial operations for updates. Reminder announcements will also play on no-treatment days between 6.00am and 12 noon.
  • Website: go to Latest Aerial Operation Update
  • Freephone: 0800 809 966 for a regularly updated recorded message.

How big is the treatment area?thumbnail of aerial operation and vegetation control zone

  • The treatment area covers approximately 1,250 hectares as shaded in yellow in the map.
  • The wind may cause some spray to drift outside this area.

What kind of aircraft will be used and how low do they fly?

  • An Air Tractor will be used during the treatment period. Alternative aircraft, including a twin-engine helicopter, will be used as back-up if required.
  • The aircraft will fly at a height approved as safe by the Civil Aviation Authority. This will ensure the best coverage of the area. For people on the ground it will feel very low and you may find it noisy.
  • The Civil Aviation Authority has approved the selected aircraft and flight procedures needed to carry out the operation.

In what direction will the planes fly in?

  • A flight path is the route the plane flies to cover the treatment area.
  • It is looped like a racetrack.
  • At the end of each run across the treatment area, the aircraft climbs and makes a wide turn that takes it outside the treatment area. While the aircraft is turning outside the area, the spray is turned off.
  • Flight path diagram.

Why does the plane fly over my property more than once?

  • The racetrack flight path means that the plane flies the distance of the treatment area in overlapping circles. Each time the plane turns it flies close to the last treatment path. From the ground it may appear that the plane is flying over the same area more than once.
  • The plane needs to refuel a number of times during an operation and may return to your area to finish treating a path it started before refuelling.

How much spray is being used in aerial treatments?

  • Aerial treatments in Hamilton use about 5-7 litres of spray per hectare. That equates to around 0.5-0.7 mililitres per square metre and is a similar to the amount used in the painted apple moth programme in western Auckland.
  • The application rate will start at 5 litres per hectare and will increase over time as caterpillars grow and leaf foliage gets more dense.
  • These spray rates were recommended by the Technical Advisory Group, with input from overseas experts on spray deposition.

Should I stay inside during an aerial operation?

  • Unless you have a specific health concern like asthma or a food allergy there is no risk to your health from coming in direct contact with Foray 48B.
  • Phone 0800 809 966 to talk to a health professional, if you have a specific health concern relating to the aerial operation.
  • Foray 48B is sticky and some people find the smell unpleasant. You will probably want to stay inside or under cover while the aircraft is directly overhead and for a few minutes afterwards while the spray settles.

Page last updated: 30 April 2008