Ve­spex key weapon in war on wasps

The Leader (Nelson) - - YOUR HEALTH - JONATHAN CAR­SON Jonathan Car­son

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.

‘‘Ve­spex is cur­rently the best op­tion for wide area con­trol be­cause it's ba­si­cally the only op­tion we have avail­able.’’ Wasps drawn to Ve­spex bait.

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