Stink Bug Heads West
April 4, 2014 Editor’s Note: The following article was provided by WSU (Washington State University) News.
An alien pest that smells like dirty socks and devours crops may become Washington state agriculture’s Public Enemy No. 1 in less than five years, government and university researchers are warning.
In the meantime, the scientists are ramping up efforts to blunt this mounting threat to the region’s fruit crop industry.
Washington State University (WSU) is one of 10 institutions across the nation whose researchers are working to head off an invasion of the brown marmorated stink bug. Tracy Leskey is the USDA entomologist leading this scientist SWAT team.
“One of the most disturbing things about this bug is its scope,” she says from her office in Kearneysville, WV. “In a relatively short period, they’ve spread to 40 states; and they’ve made it look so easy.”
No Natural Enemies
Since the brown marmorated stink bug, or Halyomorpha halys, was discovered in Pennsylvania in 1998, the shield-shaped insect from Asia has advanced down the East Coast and spread west nationwide — gorging on everything from peaches and grapes to soybeans and corn. In a single year, it took a $37 million bite out of the Mid-Atlantic’s apple crop.
“Because they’re nonnative to this country, we have no natural enemies to keep their numbers down,”says WSU entomologist Richard Zack. “They keep expanding their geographical reach and they keep multiplying.”
What’s more, the effectiveness of chemicals for pest control remains iffy: “So far, they’re not as susceptible to insecticides as we would hope,” Zack says.
‘We’ll See More’
Right now, brown marmorated stink bugs are overwintering inside people’s homes, sheds and attics, and under wood piles. Some are even stowing away to new locations in vehicles driven by unsuspecting drivers.
But come May and June, they’ll emerge to mate, lay eggs and find food, says USDA’s Pete Landolt, research leader of the Yakima Agricultural Research Laboratory in Wapato, WA.
“I expect that, in 2014, we’ll see more brown marmorated stink bugs and we’ll see them in more places in Washington,” he says. “Based on what we’ve seen happen in the eastern United States, unless we can figure out a viable strategy to control them, we could see severe crop injuries in less than five years.”
Fruits, in particular, are vulnerable to damage; Washington is the nation’s leading producer of apples, pears and sweet cherries.
So far, the bugs are most concentrated in Clark and Skamania counties, just across the Columbia River from infestations in Oregon, Landolt says. Sporadic numbers are appearing in areas such as Klickitat County, the Yakima Valley, Walla Walla and Chelan County. All are fertile agricultural areas where orchards and vineyards stretch across landscapes for miles.
Grape Growers On Alert
Winegrapes are another major crop in Washington, where more premium wines are produced than any state except California. To date, no brown marmorated stink bugs have turned up in the region’s vineyards, says WSU entomologist Jay Brunner, regional leader of the research team.
But not so in neighboring Oregon, where scientists from Oregon State University (OSU) have trapped them at three vineyards. OSU is also a member of the scientific group.
“It does attack grapes, including winegrapes,” Brunner says. In addition to puncture wounds, another concern is the potential tainting of aroma and flavor if the bugs find their way into lugs, or crates, during harvest, he says.
Hitching A Ride
These bugs can fly, but vehicles best explain how, in Oregon and Washington, they’ve settled in areas off the I-5 interstate and highways.
“They are the most amazing hitchhikers,” says entomologist Michael Bush of WSU’s Yakima County Extension. They catch rides in boxes and crates packed in cars, trucks and trailers or even in a groove between seats, he says.
Bush works with other WSU Extension scientists to teach master gardeners, field workers and the public how to tell brown marmorated stink bugs from our similar-looking beneficial native stink bugs.
The easiest way to ID the brown marmorated variety is by the thin white bands on its antennae, he says.
Wasps Might Be Key
Back home in Asia, the stink bug’s mortal enemy is a parasitic wasp that lays eggs inside stink bug eggs, destroying them. This tiny terrorist — the size of a gnat — could be released on U.S. soil to serve as a natural pest controller, says project leader Leskey of USDA.
But first, scientists must do “rigorous screening” to make sure it’s safe to introduce in this country, she says. Chemicals that lure stink bugs into traps and light intensity levels that attract them are also being looked into, she says.
For more information, go to the Stop the Brown Marmorated Stink Bug national research team’s website at StopBMSB.org.
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