COLUMBIA — A new species of stink bug is crawling closer to Missouri's borders, and this one stinks worse than the ones already here.
The brown marmorated stink bug, or "Halyomorpha halys," has been making its way across the U.S. for the past several years, damaging fruit and vegetable crops and finding its way into homes along the way.
MU Extension has been monitoring its progress and keeping an eye on when it will cross into Missouri. The concern is that this species of stink bug causes more damage than native species and is hard to control, said Pat Miller, an agronomy specialist with MU Extension.
"They have no natural controls to help moderate the numbers," Miller said.
MU entomologist Wayne Bailey said this stink bug packs a more potent olfactory punch — a "musty and repulsive" odor.
"It's made to smell bad, and it does," he said.
The stink bug gets its name from one of its defense mechanisms. When a stink bug feels threatened, it releases a chemical through its abdomen. And the feeling is contagious.
"When one goes off, they all go off," Bailey said.
Miller, who also mentioned its greater stink factor, said the invasive stink bugs hitchhike on produce. They also feed on fruits and vegetables, as well as field crops such as corn and soybeans, more so than their native cousins.
Bailey said the stink bugs target the pods of soybean plants, causing the beans to shrivel up. The bugs have the same effect on ears of sweet corn.
"We are vigilant because it's such a good hitchhiker," Bailey said.
This stink bug came from southeast Asia and is thought to have been brought over on shipping crates.
Bailey said he expects it will enter Missouri on firewood or pallets of plants. There have been two confirmed locations of live stink bugs in Illinois and one in Iowa, he said. Given that they are in neighboring states, Bailey expects Missouri will have "low-level" populations of them in the next several years.
Nine dead brown marmorated stink bugs were found in a travel trailer in Columbia this past spring, Bailey said. A couple had brought the trailer back from the East Coast during the winter, and the Missouri cold killed the stink bugs.
Bailey said these bugs might be noticed first by homeowners instead of by farmers looking through their crops. Brown marmorated stink bugs behave like Asian lady beetles trying to find someplace warm to live during the winter months. Infestations often occur when the insects live in a garden or orchard near a house and then come inside for the winter.
Bailey said the bugs often like houses with wood siding and those that use wood heat. The insects have an aggregation pheromone, and when one stink bug finds a nice, warm spot to hibernate for the winter, it lets out the pheromone inviting other stink bugs to join it.
The bugs won't harm homes as they do crops, but they will stink up the joint if bothered. The smell is sometimes potent enough to require vacating the room, Bailey said.
An adult brown marmorated stink bug is roughly the size of a dime. It can be identified by its shield-shaped shell and is differentiated from other stink bugs by white markings on its antennae, legs and stomach.
The stink bug produces one generation of offspring each year in mild temperatures. In tropical climates, it can produce as many as six generations in a year. The eggs are laid from May to August, and adults appear in the spring after going through five stages of molt.
The first brown marmorated stink bugs were collected in 1998 in Allentown, Pa., according to the National Invasive Species Information Center.
As of February 2011, this bug has been identified in 36 states and in Washington, D.C., according to an Environmental Protection Agency report.
Bailey said he thinks eventually a DNA test will be done on the bugs to find out where they came from.
He said brown marmorated stink bugs are relatively difficult to kill because of their piercing and sucking mouths. Most insecticides only kill pests with chewing mouths because the bugs chew and digest the plants that have been sprayed.
An effective method hasn't been developed yet to eliminate the population of the bug. Bailey said remedies being researched include covering the plants with a netting that the bugs cannot permeate and using insecticides previously taken off the market.
Missouri is not currently doing testing to eliminate the stink bugs because live samples haven't been found in the state. Bailey said he hopes someone finds a solution before large populations take up residence.
Miller said if people find the stink bugs, they should contact their local Extension office or the state entomologist office in Jefferson City, 573-751-5505, as soon as possible.