Study focuses on evaluating usefulness of natural predator

By JOHN SCHMITZ

For the Capital Press

CORVALLIS, Ore. -- Entomologists are developing a natural defense against an insect that could endanger numerous crops.

"We're very worried about the impact this bug may have on hazelnuts," said Oregon State University associate professor Vaughn Walton, an Extension horticultural entomologist who specializes in integrated pest control and biocontrol crop protection.

He was referring to the brown marmorated stink bug, which has already done extensive damage to a number of crops on the East Coast, and has attacked hazelnut research blocks in New Jersey.

"On the East Coast it's a tremendous problem on a wide variety of crops, including corn, soybeans, winegrapes, tomatoes, peppers -- you name it," Walton said.

While the stink bug is not yet a problem in Oregon agriculture, its presence has been shown to be increasing in metropolitan areas and spreading out from there, Walton said.

He and his associates believe they have identified a natural predator to the insect -- a wasp -- that will be released in orchards if and when the stink bug becomes a threat, thus avoiding the use of hard insecticides.

In hazelnut infestations, the stink bug does its damage by feeding on nut meats with its needlelike mouthparts. Visually, this causes corking of the meats and also discoloring similar to brown stain.

"It's a really big risk to Oregon agriculture and agriculture on the West Coast," said OSU researcher Chris Hedstrom of the stink bug. "It's already caused tens of millions of dollars of damage in all sorts of crops in Pennsylvania and the mid-Atlantic states."

Hedstrom, a master's degree candidate who has been doing most of the research on the stink bug, has been subjecting various Oregon crops to it and finding that quite a few, even conifers, are susceptible. "This thing eats anything," which is an unusual trait in most insects.

"The problem with this bug is that if you had to make a list of the plants it's found on, it would be endless," Walton said.

Some of the other Northwest crops threatened by the stink bug are blueberries, tomatoes, corn and tree nuts.

Hedstrom said it would take up to three years before predators are cleared for use on the stink bug. It's important, he said, that the wasps that feed on the bug don't also go after beneficial insects already helping to protect crops.

Hedstrom's work on determining the stink bug's potential damage to hazelnuts is being funded by the Oregon Hazelnut Commission. The Oregon Department of Agriculture is paying for developing the control program using predator wasps.

Hedstrom said that so far no traditional insecticides have been labeled for the various endangered crops that have been found effective against the stink bug. "The ones they've been trying on the East Coast have been mostly pyrethroids, but those have been largely ineffective."

Hedstrom is conducting his research at OSU's Lewis-Brown Horticulture Farm just east of campus on Highway 34.