New plans for target aerial spraying

12 December 2001

The Ministry of Agriculture and Forestry plans to extend its targeted aerial spraying programme in parts of west Auckland to improve its chances of eradicating the painted apple moth.

At this week's meeting of MAF's Technical Advisory Group, scientists recommended that MAF up the ante on the programme following a sharp increase in male moth catches in the last few weeks.

Because of delays to the spraying programme and the onset of warm weather when moths are on the move, the scientists agreed that the best option was to widen the original zone to be sprayed to include all areas where larval infestations are persisting.

This means widening the spray zone which will run from Roberts Road in Te Atatu South where it meets the Whau River along to Kelston, taking in Wairau Creek and other waterways. In some areas, the spray zone will be up to a kilometre from the water's edge. This will extend the targeted aerial spraying programme from about 300 to 600 hectares. Waikumete Cemetery, Traherne Island and Avondale Peninsula will be included as originally planned.

With legal and operational problems that had held up the programme now out of the way, the targeted aerial spraying is set to start in mid January 2002. The operation and its progress will be reviewed after three complete sprays. This will give MAF time to advise residents and not interfere with Christmas and New Year celebrations.

In the week ending 23 November, 523 male moths were caught in traps. In the following week 445 moths were trapped and during the week ending 7 December, 494. Some catches were on the periphery of the trapping area.

MAF's Director Forest Biosecurity, Dr Ruth Frampton says this is not necessarily unexpected. "With the warmer weather large numbers of male moths are emerging so we were not surprised to find them further afield.

"Also, recently we have increased the intensity of trapping there so we're catching more moths."

The trapping of a single moth in Mt Wellington and one or two male moths in Pt Chevalier and Onehunga-Penrose is not likely to be a worry because there are no reports of caterpillars, Dr Frampton says.

However, MAF is more concerned about repeat catches in the Scenic Drive area of Titirangi, and Oratia because they are close to the Waitakere Ranges. Male moth catches in these areas have increased markedly in the last two weeks.

Property-by-property ground searches have started in this area to find out if there are female moths or caterpillars present, and the trapping zone is to be extended further.

. The painted apple moth was first found in the west Auckland suburb of Glendene two years ago. The female painted apple moth does not fly, unlike its cousin, the white tussock moth which was eradicated from Auckland's eastern suburbs in 1996-97. Because of this, a "stepped" approach to eradication was taken to minimise the impact on residents without compromising the chance of success. This included property-by-property surveys followed by ground spraying operations and host plant removal if painted apple moth was found. Targeted aerial spraying was approved by the Government in late October to supplement the eradication programme.

For more information please contact:

Dr Ruth Frampton Director Forest Biosecurity (04) 498 9639/MOB: 027 435 0801
Mary-Ann Crawford, Communications Ph (09) 913 1827/MOB: 021 648 117.

Background

The painted apple moth, a native from Australia, is a relative of the white tussock moth which was successfully eradicated from east Auckland suburbs in 1996-97.

Two years ago, the moth was first discovered in Glendene, a west Auckland suburb.

Unlike the tussock moth, the painted apple female moth does not fly which limits its natural dispersal. This is why a staged approach to eradication was chosen to balance disruption to the community without compromising the eradication programme.

To date, the pest has been suppressed by ground spraying and the removal of host plant material. An ongoing comprehensive trapping programme, and visual property-by-property surveys have been conducted every 7-8 weeks to find out where the pest is.

If found, the property is ground sprayed and inspected weekly, initially to make sure the spray worked and later to make sure the pest had not returned. 5800 properties are surveyed regularly and painted apple moth egg masses, caterpillars, pupae and female moths have only ever been found on about 120. In November's survey, painted apple moth in its various life stages was collected from 47 locations but only two sites were new.

Trapping results and visual inspections show infestations persist around the edges of the Whau River and associated waterways, Traherne Island and Waikumete Cemetery - areas often inaccessible by ground spray because of the terrain, height of the trees and density of the vegetation.

In late October 2001, the Government agreed that the best option to eradicate the moth was the supplement the ground spraying and other measures with targeted aerial spraying in the hard-to-reach areas. This programme will start in January 2002.

In New Zealand the painted apple moth is a threat is to our forestry, horticulture and environment where there are few natural controls. It can feed on young pine trees (up to 8 years), affecting their growth and on many different types of plants. It particularly likes wattles and acacias but has also been found feeding on kowhai, mountain ribbonwood and recently, karaka. If it spreads, the economic cost to the country is estimated to be at least $48 million over 20 years.

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