Tracy Loew

Statesman Journal

Scientists across the U.S. are getting ready to escalate a life-and-death battle between two nonnative insects: a stink bug that damages a wide variety of crops and a tiny wasp that just might become the hero in this drama.

And Oregon is at the center of the fight.

The brown marmorated stink bug "is one of the most severe invasive agricultural pests because it feeds on so many different kinds of important crops," said Kim Hoelmer, an entomologist with the U.S. Department of Agriculture. "It is capable of doing a lot of damage."

Homeowners also complain that it infests their houses and sucks the life from their fruits and vegetables.

The pest has been in the United States since 1996 and in Oregon since 2004, said Chris Hedstrom, biological control specialist for the Oregon Department of Agriculture.

Here, it threatens hazelnuts, cane berries, blueberries, apples and pears. Those crops had a combined value of more than $433 million in 2015, the last year for which statistics are available.

“Pretty much you name it, it feeds on it,” Hedstrom said.

And, though the bugs don’t damage wine grapes, the defensive chemicals they release are a threat to the wine-making process.

Scientists have known for some time that a species of tiny wasp, Trissolcus japonicus — better known as the Samurai wasp — likes to lay its eggs inside brown marmorated stink bug eggs.

The wasps don’t sting humans, but what they do to stink bug eggs has been equated with the birth scene in the 1979 film Alien.

In the United States, the wasps haven't been able to breed quickly enough to slow the stink bugs' spread. This year, scientists will try to change that.

For the first time, they’ll rear legions of Samurai wasps in the laboratory, infest stink bug eggs and then make like Johnny Appleseed with the compromised hosts. Out will come newborn wasps, presumably dooming more crunchy insects named for the odor they emit when smashed.

Oregon will be the first to give it a try, Hedstrom said.

The state doesn’t need federal permission to release the wasps, he said, because they already have appeared here, in an area ranging from Northwest Portland to the Portland International Airport.

Map: Brown Marmorated Stink Bug

But scientists worried that releasing them could impact native stinkbugs, which are not harmful.

In 2015 ODA and Oregon State University scientists completed a study that shows that’s unlikely to happen.

This year, they released the wasps in Hood River, southern Oregon, the Willamette Valley and Milton-Freewater, said Nik Wiman, OSU assistant professor and orchard crop extension specialist.

“We’re trying to get it into areas where the brown marmorated stink bug is already established and is a major threat to important agricultural industries,” Wiman said. “We anticipate it’s going to spread on its own. But we decided to get ahead of that a little bit.”

The process is being evaluated in six other states where the wasps have been found in the wild – Washington, Delaware, Maryland, New Jersey, Virginia, and West Virginia.

And the rearing and release of Samurai wasps is expected to be approved in New York, said Peter Jentsch, director of the Hudson Valley Research Laboratory there.

Although it may appear that scientists are messing with nature, the wasps already are here, Wiman said.

“We’re just helping it along with its establishment process," he said. “And hopefully we’re saving the growers from having to use a lot of insecticides.”

tloew@statesmanjournal.com, 503-399-6779 or follow at Twitter.com/Tracy_Loew

John Ferro, Poughkeepsie (N.Y.) Journal, contributed to this report.

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