Destructive Stink Bugs Set Sights on Deep South
By: Darryl Fears, The Washington Post
3/19/2012 11:30:27 AM
On the front line of the brown marmorated stink-bug invasion, Doug Inkley was overrun. Over nine months last year, he counted, bug by bug, 56,205 in his house and garden. They were everywhere.
"I literally have made homemade chili and had to throw it out because there were stink bugs in it," said Inkley, who lives in Knoxville, Md., near the West Virginia border. "I have had people refuse to come over for dinner because they knew about my stink-bug problem."
Maybe now they'll come over. Entomologists say the population of this invasive species from Asia appears to have cratered in the Mid-Atlantic. Hurricane Irene and Tropical Storm Lee caused flooding, drowning stink bugs and snuffing out nymphs before they could develop.
But there is also bad news. The bugs have marched to the Deep South. Recently they were detected in South Carolina, Georgia and Florida, where farmers grow juicy vegetable and citrus crops that the bugs are known to destroy.
It gets worse. Another type of Asian stink bug has established itself in Georgia. It eats invasive Asian kudzu, a good thing. But the kudzu bug also eats soybeans and other lucrative Georgia legumes.
On a working trip to Atlanta last week, Inkley, a senior scientist for the National Wildlife Federation, saw them flying about, attaching to walls by the hundreds.
"Here we go again," he said.
Stink bugs come in a wide variety. Many are native to the United States, where prey insects keep them in check. Brown marmorated stink bugs native to China were discovered in Allentown, Pa., in 1998, likely after crawling out of a cargo ship.
Pennsylvania, West Virginia and Maryland, especially where Inkley lives, were particularly hard hit, for reasons entomologists have not figured out.
So far, the pest has been detected or established in the District of Columbia and 36 states, a dozen more than last year. Detected means they've been observed and confirmed through lab testing, as opposed to established, which means they have slipped into homes by the hundreds and ravaged food crops by the thousands.
In the Mid-Atlantic region, where brown marmorated stink bugs are well established, they caused an estimated $37 million in damage in apple crops alone in 2010, the most recent year for which data are available. Some farmers in Maryland said they ruined a third of their peach crop and half of their raspberries last year.
That's nothing compared with what the warmth-loving bug might do in the Sunshine State, said Douglas Luster, research leader for the U.S. Department of Agriculture's Agricultural Research Service. "It could be like the atomic bomb going off," he said last year, implying the population might explode.
"There is great fear that if the brown marmorated stink bug gets established in Florida, it will do a lot of damage," Denise Feiber, a spokeswoman for the Florida Department of Agriculture and Consumer Services, said Thursday.
Florida is testing a non-stinging parasitic wasp from Asia, a natural stink-bug predator that entomologists might unleash in October, if necessary, Feiber said. The USDA Agricultural Research Center has tested for more than a year a similar wasp that preys on stink-bug eggs, but has delayed its release for fear that it, too, could become an invasive pest.
The so-called kudzu bug of Georgia was first spotted in 2009. Back then, state entomologists had to search kudzu patches repeatedly for a sign of the insect. But as female bugs lay eggs with no natural predator, the population exploded in two years, making them easy to sweep into butterfly nets by the thousands.
Kudzu bugs are now established in 143 Georgia counties, 42 counties in North Carolina and five in Alabama, according to the University of Georgia's College of Agricultural and Environmental Sciences.
For a while, they appeared to be a kind of welcome pest. Kudzu bugs, from Japan, chomped on Asian kudzu, reducing growth of the vine by up to 50 percent, said Dan Suiter, an associate professor of entomology at the University of Georgia.
But as it turned out, the bug had a taste for other legumes, such as soybeans. It migrates from kudzu in spring to soybean in July, reducing yields by about 20 percent for two years and costing farmers millions of dollars.
On top of that, the bugs are really annoying. "They're a general nuisance," Suiter said. "I was just driving home yesterday and had one in my vehicle. They fly very well. We've found it on the 40th floor of high rises. When we first found it in 2009, they covered 2,500 square miles in the area. Their known distribution as of last fall is 108,000 square miles."
With kudzu bugs limited for now to a smaller area, brown marmorated stink bugs, which, like kudzu bugs, give off a foul bittersweet odor like rotten cilantro when threatened, get most of the attention from entomologists.
Tracy Leskey, a research entomologist for the USDA, said entomologists can't stop stink bugs, but they can slow them down. The USDA research program and its academic partners received a $5.7 million grant, allowing them to watch the bugs' every move.
So far they've learned males emit a scent that attracts both sexes, a possible signal they've found food or they want to mate. Entomologist want to use that to trap them, or "attract and kill," as she put it.
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