Tiny wasp on standby to fight de­struc­tive brown stink bugs

The Press - - News - Es­ther Taun­ton

A par­a­sitic wasp the size of a pin­head could take down the brown mar­morated stink bug.

The En­vi­ron­men­tal Pro­tec­tion Agency pre-ap­proved the re­lease of the tiny wasp ear­lier this year, the coun­try’s first pre­emp­tive ap­proval of a bio-con­trol mea­sure.

The wasp is one of sev­eral lines of de­fence against the brown mar­morated stink bug (BMSB), an in­va­sive pest which feeds on more than 300 plants and has al­ready cut a swathe through Europe and the United States.

A 2017 re­port from the NZ In­sti­tute of Eco­nomic Re­search found that if the bug gained a foothold in New Zealand, it could cost the hor­ti­cul­ture and arable in­dus­tries $4 bil­lion.

On Thurs­day more than two dozen live BMSBs were re­ported to have been found in a box of shoes im­ported into

New Zealand from EBay. The in­ci­dent was re­ported just a week af­ter three live and 39 dead BMSBs and 69 other reg­u­lated stink bugs were found aboard a ve­hi­cle car­rier an­chored off Auck­land. The ship was di­rected to leave New Zealand wa­ters.

Dr David Teu­lon, di­rec­tor of Bet­ter Border Biose­cu­rity (B3), said any find of a small pop­u­la­tion of pests like the BMSB was con­cern­ing.

‘‘BMSB is a po­ten­tially very se­ri­ous pest to many of our val­ued plant sys­tems, both pro­duc­tive and nat­u­ral,’’ he said.

‘‘But it is also an im­por­tant ‘so­cial’ pest, as it is known to in­vade dwellings in large num­bers.’’

B3 is a co­op­er­a­tive science col­lab­o­ra­tion that re­searches ways to keep new pests and dis­eases out of New Zealand.

Teu­lon said the BMSB was recog­nised as one of the more prob­lem­atic biose­cu­rity threats the coun­try faced.

‘‘The pre-emp­tive ap­proach [to con­trol­ling it] is con­sid­ered a world first, and is recog­nised by the in­ter­na­tional com­mu­nity as an ex­am­ple of New Zealand do­ing things right.’’

The wasps do not sting hu­mans but are a nat­u­ral en­emy of the stink bug. The fe­male wasp lays her eggs in­side stink bug eggs, and the wasp lar­vae eat their way out, killing the de­vel­op­ing stink bugs in the process.

Stud­ies over­seas have shown that the samu­rai wasp can de­stroy more than 80 per cent of stink bug eggs. If the stink bug be­came es­tab­lished in New Zealand, samu­rai wasps could be im­ported, most likely from the US.

The wasps could only be re­leased af­ter a stink bug in­va­sion has been de­tected, and only at the lo­ca­tion of the in­cur­sion. Any re­lease would need Min­istry for Pri­mary In­dus­tries ap­proval.

Teu­lon said the stink bug posed sev­eral unique chal­lenges for New Zealand, in­clud­ing that it hid in many com­modi­ties that crossed the coun­try’s border and was dif­fi­cult to find and kill. ‘‘The cur­rent pheromone at­trac­tants are not as strong as oth­ers used in biose­cu­rity.’’

Fed­er­ated Farm­ers biose­cu­rity spokes­woman Karen Wil­liams said the lat­est dis­cov­ery of the bugs was ‘‘very scary stuff for our na­tion’s grow­ers’’.

More than two dozen live brown mar­morated stink bugs were found in a box of shoes or­dered on­line this week.

A samu­rai wasp

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