Fruit & Vegetable Magazine

From the Editor: Invasive pests, invasive predators

March 31, 2020  By Stephanie Gordon

The theme of April’s issue is pests and diseases and our cover story is all about stink bugs. For some, stink bugs are a pest, for others, they’re just boring bugs. But the brown marmorated stink bug (BMSB) is anything but boring.

BMSB is an invasive pest from Asia that is prominent in the U.S. with no major enemies to keep its population in check – until recently. A 2018 Science Magazine feature story revealed: “Scientists spent years on a plan to import this wasp to kill stink bugs. Then it showed up on its own.”

The article sets the stakes: In 2010 stink bug damage cost mid-Atlantic apple growers $37 million. It describes the obstacle: without any natural enemies, the brown marmorated stink bug has been free to roam across 43 states and Washington, D.C. Then, the article offers a glimmer of hope: USDA-ARS scientists traveled to Asia to find natural enemies of the stink bug to bring back home.


The samurai wasp, a small “sesame seed” sized parasitoid wasp, emerged as a possible biocontrol candidate. The USDA-ARS scientists imported several strains of the samurai wasp to the U.S. to begin research. This was in 2005. In 2014, the project lead got a phone call that samurai wasps were spotted in Maryland. Genetic tests were done to make sure they weren’t wasps that escaped from the lab, and once they realized they weren’t, another fact became clearer. The samurai wasps had immigrated on their own.

Since then, according to the 2018 article, the wasp turned up in 10 states and Washington, D.C., and so far, research studies are seeing the samurai wasp emerge as a promising biocontrol without harmful side effects.

Why is this important? News like the samurai wasp immigrating on its own gives hope. Invasive predators can help us deal with invasive pests – assuming they don’t upset the ecosystem balance too much. It reaffirms that our environments are always in a state of flux and our ecosystems are delicate, dependent, and unpredictable.

So what threat does BMSB pose to Canadian growers today, and what’s the status of samurai wasps north of the border? Read the full story on page 10. You can also read about how drones can become “technological predators” that can help producers spray more efficiency for pest control on page 14.

It may seem like we’re dealing with the same threats season after season, but pest migration, pesticide re-evaluations, weather changes, and technology innovation are going to continue to change our pest landscape. Will the pest threats covered in this issue matter in 10 years? Or will there be new pests lining the pages of our future issues? Coming into planting season, I hope this pest-themed issue helps you stay aware of what’s to come, and like the samurai wasp, I hope only beneficial surprises come your way.

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