And, there may be predators here that will attack the wasp.
In addition to the Asian parasitic wasp, there are some native predators of the stink bug that attack at the egg stage in early June or July, including katydids and crickets and jumping spiders, as well as lacewings. Generalist predators such as praying mantis will eat stink bugs, even in the adult stage.
Also, there is a fly that will lay eggs on the adult stink bug, and in the Eastern U.S., a sand wasp has been discovered that will sting the bug, bury it and feed it to its offspring. However, Abram says the best long-term solution seems to be an egg parasitoid such as the Samurai Wasp.
Abram had been working on research into parasitoids of stink bugs in Montreal when the job at Agassiz came up, so it seemed like perfect timing.
He had been interested in insects since he was a youngster living in a rural community in Ontario and worked in the Ontario ministry of agriculture at summer jobs scouting apple orchards and vineyards for pests.
He become interested in biocontrols and split his time between Ottawa and Switzerland for a time, doing research into insect pests.
As well as BMSB, Abram is researching parasitoids from the Pteromalid family of wasps that could attack Spotted Wing Drosophila. It is already present in the Fraser Valley and attacks a wide variety of fly pupae.
“We’re looking at the potential of it as a control, but need to ensure it will stick around if we introduce it to a berry field,” he explains. In fact, Abram says they are looking at possibly ‘pre-training’ the wasps they would release, to look for the sort of habitat SWD are found in around berry fields, to ensure they will stay and attack SWD when they arrive.
As well, he says they are looking at what parasitoids there are in Asia and how effective they are. “Fruit flies are tricky to find a solution to,” he comments, adding, “So importation of a beneficial might be part of the answer. That way their populations would cycle with those of the pest.”
18 British Columbia FRUIT GROWER • Fall-Winter 2017
Research scientists still don’t have a handle on where and how SWD overwinter, although it appears that the harsher Okanagan Valley winter last year has helped to dampen populations. SWD was first identified in B.C. in 2009 and is a pest of soft-skinned fruit such as cherries, laying its eggs in ripening fruit and leaving it soft and un-marketable.
Abram remains optimistic that a biological control for SWD will be found, despite the complexity of the problem.
“Ecosystems adopt these new pests and in time a native predator will discover them,” he notes. Until a biological solution to the risk posed to crops by both these alien pests is found, it’s important
that growers be aware of both pests, know their life cycles and be able to identify them.
Entomologists with the B.C. Ministry of Agriculture ask that anyone discovering a BMSB submit it to the ministry; take photos and send them in to ensure a positive identification.
So far, none have been discovered on farms, just in urban communities, from residential areas in Vancouver to downtown Kelowna; weedy fields in Penticton to a condo complex and houses in Chilliwack and urban parks in Langley.
However, if some have been found there are bound to be more that haven’t yet been identified, but that are already here, so there’s plenty of reason to be concerned.
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