Wasps on the wane but sting may be in summer's tail

By Philip English

Wasp numbers are reported to be low this summer, but pest control officers fear the menace could grow as the warm weather lingers.

Wasps make life a misery for many holidaymakers and picnickers, especially young children, but since the summer of 1994-95, when populations peaked around the country, the insects have been barely noticeable in much of the North Island.

The worst area for wasp infestations is native beech forests around Nelson where the insects feed on honeydew on the trees, competing for it with native birds.

Richard Toft, of Landcare Research in Nelson, the country's main centre for wasp research, said indications were that numbers would be low this season.

But it was still early. Wasp populations usually peaked in March and April.

High densities could also occur in some places but not others.

Mr Toft said warm, dry conditions in spring were the best for wasps. The Nelson area's heavy downpours last year would have flooded nests, causing the low numbers.

"Last year El Nino did some very odd things to the wasps. There was quite a high density of nests but all the nests were very small.

"So whether there is some sort of flow-on effect that might occur this year as well I don't know."

In the North Island, regional pest control officers from Northland to the Bay of Plenty reported low numbers but were cautious when it came to predicting whether they would stay low all summer.

David Moore, pest coordinator for the Bay of Plenty regional council, Environment BOP, said that just when he was beginning to think numbers of German and common wasps were down again, he got a report of big infestations at Lake Rotoma near Rotorua.

He was sure, however, that the infestation was isolated.

Low numbers of wasps elsewhere in the region were confirmed by an increase in butterflies - "a pretty good indication that wasps are just not about," he said.

Flourishing Asian paper wasps were more of a problem in coastal areas around Tauranga and Te Puke.

"They are quite vicious stingers but if you leave them alone they are not like the German or common wasps. They will not come and mob you and try to hypnotise you.

"Left alone they will just go about their business."

The German and common wasps looked similar.

Mr Moore said an Asian paper wasp nest looked like half a tennis ball hanging
upside down in trees and shrubs.

Those wanting to get rid of the nests should wait till the evening, spray them with insecticide and then snip the nests off before burning or freezing them.

People should be more wary of the underground nests of the other wasp species and call in professional exterminators if the nests were large.

The pest management officer for the Northland Regional Council, Carl Cooper, said lots of nests might have survived the mild winter in the north, suggesting that populations had yet to peak. This would happen by the end of April.

Pictured: Paper wasps can be vicious.