Vespex key weapon in war on wasps
The most effective method of wasp control to date took close to 15 years to be approved for public use. tells the story of of the Wasp Vespex as part
Wipeout project.
As an eight-year-old, Richard Toft watched the apple tree at his family home in Kerikeri get ‘‘eaten alive’’ by wasps.
Back then, he created a makeshift bait station — an inverted jar with jam inside and a funnel entranceway to trap the wasps. ‘‘That sort of triggered a natural interest in wasps,’’ Toft says.
The curious boy from Kerikeri has become one of New Zealand’s pioneers of pest control.
Since joining the now defunct Department of Scientific and Industrial Research in Nelson in the late 1980s, he has worked with other scientists and the Department of Conservation to develop a viable control method for German and common wasps.
Last year, following a remarkably successful trial period, the protein-based bait Vespex that Toft developed in his Nelson laboratory was finally approved for public use.
It was a major breakthrough in a journey that has spanned more than two decades. organic chlorine pesticide, that was abandoned after being found to be ‘‘very nasty to people and the environment’’.
Sulfluramid showed promise, but ‘‘potential issues’’ has seen it phased out in much of the world, including New Zealand.
It wasn’t until the early 2000s that Toft and others started experimenting with fipronil, an insecticide that disrupts the insect central nervous system.
‘‘The reason we really like fipronil is its mode of action,’’ Toft says. ‘‘It’s incredibly toxic to insects, very safe to birds and mammals.’’
In the early days, they would mix fipronil powder with fishbased cat food. In late summer, when the wasps start feeding on protein, they would place the makeshift bait throughout the beech forest.
The results were astounding. The toxicity of some previous insecticides killed wasps before they could return to the nest. With fipronil, however, wasps could collect the bait, fly back to the nest and distribute the poison throughout the colony.
‘‘It only takes minuscule amounts of that toxin in that nest environment to actually have a lethal effect,’’ Toft says.
‘‘It takes a few hours so they’ve got plenty of time to circulate it. Once it’s active it’s very quick. The nest basically collapses overnight.’’
A study, published in 2001, found that fipronil reduced wasp activity in areas of Nelson Lakes National Park by 99.7 per cent. long-term protein source. Once it went bad, the wasps lost interest in it.
With the help of DOC, he also had to determine the optimum spacing for bait stations and he had to convince the authorities that fipronil posed no risk for honey bees.
‘‘There’s absolutely no palatability commercially or environmentally for a product that is any threat to honey bees because the world’s a very sensitive place without honey bees.’’
Beekeepers are now the biggest users of Vespex, Toft says.
Until more advanced biological controls are developed, Vespex is the best method available, Toft says.
‘‘Vespex is currently the best option for wide area control because it’s basically the only option we have available.’’ bait station nailed to a tree or post.
Once it’s done it’s job — usually within three to eight days — the remaining bait is collected from the station.
‘‘It’s all about balancing the risk,’’ Toft says.