The Associated Press

SALEM — A bug that attacks fruit crops and has caused major damage in the Eastern United States has shown up this month in the Oregon towns of Hood River and Rogue River.

The brown marmorated stink bug has been in the United States since the 1990s and in Oregon since 2004. But the latest reports are worrisome because the bugs are now near famous cherry, apple and pear crops in the Columbia Gorge and Southern Oregon, according to the agricultural publication the Capital Press.

“This thing is a major agricultural pest, and it goes after orchard crops,” Oregon State University entomologist Peter Shearer said. “We suspect there is an infestation that has started in Hood River.”

In addition to orchard fruit crops, the pest attacks wine grapes and hazelnuts, Shearer said, putting at risk two prominent Willamette Valley crops.

The brown marmorated stink bug is shaped like a shield and is about the size of a thumbnail. It has a geometric pattern on its lower abdomen and two white bands on its antennae. “Marmorated” means marbled or streaked.

The bug’s stink comes from the pungent, acrid odor it can emit when disturbed. It overwinters in hibernation in warm places such as houses, but it doesn’t bite humans.

The insect is believed to have come from Asia, where it is also a pest. It feeds on crops, rendering them unsellable, and the damage it causes provides entry points for pathogens. It spreads by hitching rides on vehicles.

The stink bug was first detected in Oregon eight years ago in Portland. It has since been found in Salem, Corvallis, Sandy, Troutdale, east as far as Arlington, and in Deschutes County. The pest also has been found in Vancouver, Wash., and near Longview, Wash., and it was recently found in Idaho for the first time, in Nampa.

Substantial effects

Shearer said it took several years for the pest to expand from cities to crops in the mid-Atlantic region, but when it did, the effects were substantial.

“In 2010, the population exploded,” Shearer said. “It destroyed 50 percent of the Pennsylvania peach crop, and did $40 million in damage to the mid-Atlantic apple industry.”

The pest also attacks sweet corn, vegetables, soy beans, field corn and ornamentals, Shearer said.

“It is just a matter of time before it becomes an issue in our cropping systems,” he said.

Shearer and other scientists are working on what he says could be a defense: a parasitic wasp that feeds on the bug’s eggs.

“We know that it is effective in the lab,” he said.

“The concern is screening this against our native stink bugs,” he said. “There are beneficial stink bugs that are predators, and we don’t want this parasite to attack them.”