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Questions & Answers - Painted Apple Moth

About the pest

Q. When did painted apple moth arrive in New Zealand? A. It was discovered in Glendene, west Auckland, in May 1999 but it is likely it had been in New Zealand for at least six months before it was found. Five months after the Glendene find, it was discovered in Mt Wellington.

Q. Where did it come from? A. It is a native of Australia – it’s not found anywhere else in the world

Q. Is it a pest in Australia? A. It is considered a minor pest on apple trees in Australia because it is controlled by pesticides that are applied for other apple tree pests. It has caused low level defoliation in pines. The New Zealand situation is different because of the potential threat to our native trees.

Q. How did it get here? A. Not sure, but because it was found in an industrial area it is possible it came on a shipping container.

Q. Where is it now? A. It has been found in Avondale, Glendene, Glen Eden, Kelston, Titirangi and Mt Wellington.

Q. What does the caterpillar look like? A. It is a brightly coloured and is distinctive because it is very hairy and has tufts of hairs on its back.

Q. How do you know where it is? A. A monitoring programme using live females in traps to catch male moths, as well as visual inspections for caterpillars has shown infestation in some areas around the Whau River estuary, on Traherne Island and at the Waikumete Cemetery. Male moths have been trapped in low numbers over a wider area surrounding this epicentre but visual surveys have found few other life stages. In total from over 3000 properties surveyed, just over 100 have been found with painted apple moth. Control measures have kept it to no more than 25 properties at any one time.

Q. Why hasn’t it spread further? A. Ground spraying and vegetation removal have controlled the spread. Additionally the female painted apple moth does not fly so its natural dispersal is limited.

Q. How does it spread? A. Male moths can fly, and newly hatched caterpillars can produce silken threads which may be caught in the wind allowing the caterpillars to “ balloon” onto other foliage, up to a few hundred metres away. The pest can also be spread by piggybacking on removed vegetation or by the caterpillar crawling among trees.

Q. What does it eat? A. It feeds on many different types of plants but particularly likes wattle and acacia trees. It has also been found on Kowhai and Ribbonwood.

Q. How much of a threat is it to the Waitakere ranges? A. Because it has been found on two native plant species so far, it is possible it could damage other native species in the Ranges

Q. Has it spread to Traherne or Pollen Islands A. There have been caterpillars found on Traherne Island but none on Pollen Island.

Q. Now that it has been found on Traherne Island isn’t it likely to spread to Pollen Island? A. No, because there is no known vegetation on the island that the caterpillar likes to feed on.

Q. Why is it considered a pest? A. It is a potentially serious threat to New Zealand’s pine forests, horticulture and environment.

Q. What could it do to our forests? A. It could defoliate the trees and limit their growth.

Q. Why has it taken so long to eradicate? A. Eradication of pests is never easy. In the case of painted apple moth MAF took a conservative and responsible approach which balances the desire to eliminate the pest with minimal disruption to residents in the area. Because the natural dispersal of the pest is limited there was not the same urgency to consider more aggressive approaches in the first instance - like aerial spraying.

Q. Is eradication really feasible after this time? A. The Technical Advisory Group set up to advise MAF considers eradication to be feasible, as did an independent review team.

Q. What has MAF been doing over the last two years? A. The pest has been controlled by ground spraying and the removal of host plant material. A trapping programme and visual property by property surveys have been conducted every 6 –7 weeks to define where the pest is. If the pest is found on a property, control measures such as ground spraying are undertaken and the property inspected weekly for signs of re-infestation. Of the approximately 3000 properties surveyed, painted apple moth has been found on just over one hundred.

Q.What would the cost be to the country if it was allowed to spread? A. At least $48million over the next 20 years.

Q. How do I recognise the pest? A. Unlike other caterpillars in New Zealand it is hairy. It has distinctive tufts of hair on its back.

Q. What do I do if I think it’s on my property? A. Telephone 0800 809 966 and someone will contact you and possibly visit to check it out.

Q. Is the caterpillar harmful? A. Some people may be allergic to the caterpillar’s hairs, but they are not a health hazard to most people

Q. Why aren’t there more restrictions on the removal of garden waste from the area? A. It is only considered necessary to apply restrictions on the removal of garden waste to those properties on which painted apple moth has been found during visual surveys or their neighbours.

Ground spraying

Q. What spray is being used? A. Decis Forte (Deltamethrin) is a synthetic pyrethroid registered for use in New Zealand and many other countries including USA, UK, Europe and Australia.

Q. How safe is it? A. Despite its widespread use, there have been no reports of deltamethrin causing significant problems. Accidental exposure to the concentrated product at very high levels has been occasionally reported to cause skin numbness or tingling but no long- term effects. No such reports have been recorded from exposure to the diluted spray.

Q. What else is it used for? A. It has been widely used by horticulturists, particularly on vegetable crops, for about 15 years as a treatment for caterpillars and other insect pests.

Q What precautions should residents take? A. People should not enter the treated area until sprayed surfaces are fully dry (about three hours) without wearing shoes, trousers and long sleeved shirts. Gloves should be worn if the trees need to be handled in the first 24 hours after spraying.

Q. How often are properties being sprayed? A. Only four times, at 10-14 day intervals, unless the pest is found during subsequent weekly checks.

Q. Will it affect neighbouring properties? A. It is unlikely to affect neighbouring properties but they are advised of the spraying so they may take precautions if they wish.

Q. Why isn’t Btk being used to ground spray? A. It is not as effective as Deltamethrin, which affects more than just caterpillars.

Aerial spraying

Q. Why is aerial spraying necessary? A. Ground spraying has been less effective around the Whau River and associated waterways and in the Waikumete Cemetery because of the height of the trees and the difficult terrain. Aerial spraying is the only way to reach larvae high in the canopies of inaccessible trees.

Q. Aren’t there other alternatives? A. There are no known viable alternatives

Q. Wouldn’t it be better to increase ground spraying and remove more host vegetation? A. This would not solve the problem of inaccessibility. Additionally, if more host removal was undertaken, the pest would just move to another host in the area – it is known to feed on a number of different plants.

Q. Over what area will there be aerial spraying? A. Targeted aerial spraying is planned for a 300 hectare area of the Whau River and Wairau Creek margins and in the Waikumete Cemetery, as well as Traherne Island.

Q. How many people will be affected? A. There are estimated to be about 800 residences in the area, but some of these are industrial

Q. What precautions should they take? A. All households and industrial sites within 100 metres of the spray zone will receive advice about precautions they may wish to take. As a general rule people will be advised to stay inside while spraying is taking place.

Q. How will I know when it is going to happen? A. Information will be delivered to those in the affected area, public notices will appear in local community papers and radio will also be used to notify people when the spraying is scheduled. If it has to be cancelled because of weather, further radio announcements will be made. Those people who have particular concerns can contact MAF who will make sure they are personally advised what is happening.

Q. How many aerial sprays will there be? A. It is expected there will be six to eight sprays but the number will depend on the weather, as the spray cannot be effective if the rain washes it off.

Q. How long will there be between sprays? A. The spray will be applied at intervals of three to four weeks.

Q. How will the spray be applied? A. By helicopter.

Q. How far will it spread ( spray drift) – how do you know? A. The area will only be applied on fine calm days. Modelling has been done which highlights the conditions that will minimise drift.

Q. Will Traherne or Pollen Island be sprayed - what about the native caterpillar on Pollen Island? A. Only Traherne Island where painted apple moth has been found will be sprayed. There is no need to spray Pollen Island. Regardless, experts have recently confirmed there are no native caterpillars on Pollen Island that require special protection.

About Btk

Q. What is the spray? A. The spray is Btk – Bacillus thuringiensis var. kurstarki – which is an organic insecticide containing a bacteria that occurs naturally in soil, water and air in most countries in the world, including New Zealand.

Q What are its components? A. This information is commercially sensitive and is confidential to the manufacturer but has been closely examined by medical experts so that appropriate advice can be given to individuals with particular health conditions.

Q. How does it work? A. It is sprayed on leaf foliage, which has to be eaten by the caterpillar to be effective.

Q. Has it been used before in this way – here or overseas A. It was successfully used in the eastern suburbs of Auckland in 1997/97 to eradicate white-spotted tussock moth (Operation Ever Green), and it has been used to control caterpillar pests such as gypsy moth in Canada and the USA.

Q. What else does it kill? A. Btk is specific to the caterpillars of moths and butterflies, so it is likely to affect all exposed young caterpillars. However the native caterpillar populations are expected to quickly recolonise from the surrounding areas, particularly given the targeted approach.

Q. Is it used in New Zealand for anything else? A. New Zealand organic growers have been using Btk since 1984 to protect agricultural crops and fruit trees, and it has been used overseas for more than 40 years.

Q. How safe is the spray? A. Applied at the appropriate rates it does not harm people, plants animals or any insects – only caterpillars. This is because the bacteria only becomes active in the caterpillar’s uniquely alkaline gut.

Q Does it harm fish? A. No

Q. Does it harm people? A. No

Q. Does it harm animals? A. No

Q. Does it harm other caterpillars A. Yes, but they are expected to recolonise fairly quickly from outside the area.

Q Does it affect the soil, plants or food A. No

Q. How long does it remain in the soil / atmosphere? A. Only a short time because the bacteria are adversely affected by ultraviolet light.

Q. What volume will be sprayed?

A. Btk is mist sprayed at 5 litres per hectare (one hectare is an area slightly bigger than a football field)

Q. Has an environmental impact report been done? A. An environmental impact report was done in 1996 when Btk was used to eradicate white-spotted tussock moth. This will be reviewed to include the potential impact on maori cultural issues and on rare native caterpillars in west Auckland.

Q. What did the 1996 report say? A. It found that spraying with Btk is not likely to have any long-term adverse effects on New Zealand’s soils, waters, plants food sources or (native) mammals, birds and fish. It found that non-targeted moth and butterfly species could be affected but that migration would restore populations within three years of a spray programme. Moths and butterflies with restricted distribution may be more adversely affected. Other non-targeted invertebrate species would not be affected.

Q. Can I get a copy of the report? A. Yes, when the review has been completed.

Q. Where is the insecticide made? A. In the United States.

Q. What are the chances of it being contaminated, with anthrax for example? A. MAF is making sure there are the highest security precautions in both America and New Zealand.

Q. What about schools, hospitals etc in the spray zone. A. If schools and hospitals are identified in the spray zone they will receive special information about any precautions they could take.

Q. What do the Department of Conservation / Forest & Bird say about it? A. Both are supportive of pursuing eradication as it protects our native forests for the long term.

About health

Q. How safe is Btk? A. An independent health report was commissioned at the time Btk was used to eradicate the white-spotted tussock moth in 1996/97. It found that there were no adverse health affects, although some people did experience minor respiratory irritations at the time.

Q. I am pregnant / have an allergy / MSE etc – what should I do? A. If you are in the spray zone it would be wise to close your windows and stay inside while the spraying is taking place. Some people may wish to leave the area during the period although there is no medical evidence to suggest this is necessary. MAF will set up a system to personally advise those people with significant concerns about the spraying dates and times.

Q. I’ve heard about the health monitoring programme – am I part of it? A. People in the spray zone who go to their doctor with health concerns they or their doctor think could be caused by the spray will automatically become part of the programme.

Q. I can’t afford to go to the Dr if I think the spray has affected me – what should I do?

A. A medical consultant will be engaged to assess any health problems thought to be attributable to spraying at no charge to the persons concerned.

Q. How do I access this service? A. There will be a well publicised 0800 number.

Q. I can’t afford to leave the area – what should I do? Will MAF pay for me to leave? A. There is no evidence to suggest you need to. MAF will be advising all people in the spray zone of precautions they can take.

Q Will there be health monitoring? A. Yes. Included in the study will be will undertake pre and post assessments targeting particular health concerns, but not those adequately addressed by the previous study.

Q. Will this include congenital thyroid? A. Yes, through assessing results of the Guthrie Test given to newborn babies.

Q. Who will be involved? A. Basically the same group of independent health professionals will oversee the programme as were involved in the study which took place when Btk was used to eradicate white-spotted tussock moth, i.e. Dr Francesca Kelly, Independent Medical Adviser to MAF, Dr Virginia Hope, Medical Officer of Health, Auckland Health Board; Mr Alistair Stewart, Dept of Community Health, University of Auckland, Dr Chris Frampton Christchurch Clinical School; Dr Phil Weinstein, Dept of Public Health, Wellington School of Medicine; Professor Alistair Woodward, Dept of Public Health, Wellington School of Medicine.


Q. How much has the eradication programme cost so far? A. The Government has committed $2.5million to the programme so far.

Q. How much will the next phase cost? A. The proposed programme is expected to cost between $7.908 and $11.122 over three years, depending on the number of aerial spray applications required, the area to be sprayed and the time it takes to develop a synthetic pheromone based attractant.

Q. Why has it taken so long to develop a synthetic pheromone? A. Synthetic pheromones are very difficult to develop – it may often take up to four years. Additionally in this case it has not been easy to synthesise the identified components, one of which is very unstable and therefore hard to manufacture.

Q. Does the programme require consent under the Resource management Act? A. No, it is exempt under the Resource Management (Exemption) Regulations 1996. To get this exemption, the programme requires the joint authorisation of the Ministers of Forestry, Conservation and Health.

Q. Have you consulted with Maori? A. MAF is working with Maori liaison people at Waitakere and Auckland City Councils, as well as the Auckland Regional Council and Te Puni Kokiri

Q How can I get more information? A. Visit MAF’s website - apple-moth.

Q. How will you keep residents informed? A. Residents in the spray zone will receive regular written updates on the programme as well as notification of when the spraying is going to take place. There will also be an 0800 number they can call. Community newspapers will be used to get information to all west Auckland residents as they have an interest in the programme and local radio will be used to advise when aerial spraying is taking place and if there is any change in plans because of bad weather.


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