Photo courtesy of Oregon Department of Agriculture A parasitic wasp that originates in the stink bu
Researchers are optimistic about the prospects of using a natural enemy to suppress the brown marmorated stink bug, an invasive species.
A parasitic wasp that originates in the stink bug’s Asian homeland, Trissolcus japonicus, could be a valuable weapon against the pest, said Barry Bai, entomologist with the Oregon Department of Agriculture.
“So far, they show good potential because they prefer the target host,” Bai said during the recent Pacific Northwest Pest Management Conference in Portland, Ore.
Brown marmorated stink bugs were first discovered in Oregon a decade ago.
Although economic damage from the pest has not yet been recorded in Oregon, the insect has caused severe destruction elsewhere and poses a threat to fruit, vegetable, hazelnut and ornamental crops in the state.
Trissolcus japonicus wasps lay their eggs within the stink bug’s eggs, preventing the pest from emerging, Bai said.
“That way the stink bugs won’t hatch out,” he said.
While the wasps wouldn’t entirely wipe out brown marmorated stink bugs if released into the wild, they may keep the population low enough to prevent economic harm, Bai said.
However, researchers from ODA, USDA, Oregon State University and other institutions must first determine if the wasp is effective in our environment, he said.
Tests indicate that the wasps prefer to invade the eggs of the brown marmorated stink bug more than related species, which is a good sign, Bai said.
Researchers don’t want the wasp to spread itself thin by attacking the eggs of non-target species, he said. “We want to be host-specific.”
The wasp generally avoids laying its eggs into the eggs of related species, with the exception of the Banasa stink bug, or Banasa dimiata, according to Bai’s research.
When given a choice between Banasa stink bugs and brown marmorated stink bugs, though, the wasp prefers the latter.
The wasp is a “promising candidate” for biological control but the USDA will likely require another two to three years of testing before it’s approved for release, Bai said.