By Linda Weiford, WSU News
VANCOUVER, Wash. – Why an insect the size of a fingernail has been compared to a great white shark is becoming more apparent as the brown marmorated stink bug accelerates across the Pacific Northwest.
“They’ve got to be stopped,” said Joe Beaudoin of Vancouver, Wash., who bears the distinction of being the first farmer in the region to do battle against the invasive pest whose appetite leaves boreholes in fruit and vegetable crops.
“I’m concerned that the damage they’ve done here is just a tip of the iceberg for area crops,” he said, referring to the apples, pears, sweet peppers and, most recently, pumpkins that the insects destroyed on his 90-acre farm in Vancouver’s city limits.
Ruin and stink in their wake
It’s a concern shared by government and university researchers nationally as they monitor the bug’s advance and try to reduce the mounting threat.
“We’re getting more reports of new locations where they’ve shown up. It’s clear that populations are growing and dispersing,” said entomologist Todd Murray, director of Washington State University’s Skamania County Extension.
He is among a group of researchers working with Beaudoin and other growers to control the pest. WSU, Oregon State University (OSU) and the U.S. Department of Agriculture (USDA) are part of the nationwide effort.
Originally from Asia, the brown marmorated stink bug landed in the eastern U.S. in the late 1990s. Now in 41 states, its whereabouts in the Northwest range from the moist, lush areas near Portland, Ore., and Seattle to semi-arid lands around Yakima, Walla Walla and the Tri-Cities in Washington.
“As they make their way from the Mid-Atlantic states, we’re learning more about how they behave and what they feed on,” said Murray. “Unfortunately, when it comes to climate and food, they’re not very choosy.”
Unlike most insects, these bugs eat many plant species, he said. Not only do they leave behind soggy brown pockmarks, but another concern is that they can transmit a bad flavor or odor as they feed on smaller, more delicate crops such as grapes.
Pumpkin eaters
The stink bug species was first detected in Portland in 2004. From there over the Columbia River I-5 interstate bridge and into Vancouver is Joe’s Place Farms, run by Beaudoin. His was the first farming operation to “identify significant stink bug damage to crops,” said Murray who, teaming with scientists at OSU, sets odor-attractant traps for the insects.
Because stink bugs deftly catch rides in boxes and crates packed in cars, trucks and trailers, colonies have settled in and around urban areas off of I-5, Murray said. Though the bugs can fly up to 15 miles a day by themselves, “they travel quite well as stowaways,” he said.
“Joe’s uniqueness of being located in an urban area made him susceptible to be the insects’ ‘first hit’ in the region,” Murray explained.
Last growing season, the stink bug invaded multiple rows of Beaudoin’s apples, pears and sweet peppers. This year, they drilled into his elegant French heirloom pumpkins that resemble Cinderella’s horse-drawn carriage.
Large deep-orange pumpkins with dense rinds, “they couldn’t withstand a tiny single penetration by a stink bug,” said Beaudoin. “They looked injured, bruised. I just left them lying in the field.”
Small but mighty
The marmorated stink bug’s culinary victory over an object a thousand times its size and weight doesn’t astound USDA entomologist Tracy Leskey, who leads the scientist SWAT team from her base in Kearneysville, W. Va.
“They seem to have no trouble penetrating tree bark to get sap so it’s not surprising that they can get through the thick, tough skin of pumpkins,” she said.
The pests destroy crops by injecting a salivary enzyme that breaks down tissues so they can suck out the juices. This process opens the pathway for secondary rot to develop, said Leskey, further setting the stage for a big pumpkin to decay.
What is surprising, she said, is that these tiny critters never seem to give up – surviving pesticides, cold winters, dry climates and long hitchhike journeys on trains and vehicles. One morning, she watched a throng of them feed on a newly planted ornamental maple tree.
“Their mouthparts were going right through that lovely tree’s bark,” Leskey recalled. “I remember standing there and saying out loud, ‘Aren’t you guys ever going to give up?’”
Until scientists can figure out how to stop them, the answer is “No.” Which is why, as winter approaches, the pests are seeking warm homes to settle into until spring.
Know your stink bugs
“We’re definitely getting more calls from people wondering if what they’ve found crawling on a wall or the carpet is a marmorated stink bug,” said WSU entomologist Richard Zack at the Pullman campus. “It’s good they’re asking us. We want the public to know that not all stink bugs are the marmorated variety.”
That’s because not all stink bugs are crop destroyers. In fact, some native species are actually beneficial, said Zack, because they eat other insects that harm crops.
Good or bad? To help homeowners and master gardeners know the difference, WSU has designed a “Pest Watch” guide. See http://cru.cahe.wsu.edu/CEPublications/FS079E/FS079E.pdf.
For more information on work being done by members of the national research team, go to http://www.stopbmsb.org/.
Contacts:
Todd Murray, entomologist, WSU Skamania County Extension, 509-427-3931, tmurray@wsu.edu.
Richard Zack, entomologist, WSU Pullman, 509-335-3394, zack@wsu.edu
Linda Weiford, WSU News, 509-335-7209, linda.weiford@wsu.edu