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In 2009, the kudzu bug, Megacopta cribraria (F.), also known the bean plataspid, lablab bug, or globular stinkbug, was reported in nine counties in northeastern Georgia. The following year, the insect had been found in more than 60 counties North Carolina.
Since then, surveys by NCSU Entomology Department and the N.C. Dept. of Agriculture and Consumer Services have confirmed the presence of the kudzu bug in kudzu patches and soybean fields in more than 55 counties. It is likely present in many other counties, but simply has not yet been seen there.
Kudzu bugs are 4-6 mm long (about 1/4 inch), somewhat oblong in shape, and olive-green colored with brown speckles. They are “true bugs” and so they have piercing-sucking mouthparts. Aside from kudzu, these insects are known to feed on a wide variety of legumes (soybeans and other bean species, as well as wisteria and some vetches).
Kudzu bugs have several generations per year. In the spring, they feed extensively in kudzu patches and on other legume hosts. In July-August, they will move into soybeans where they feed on stems and foliage and can have a significant impact on crop yields. The bugs continue to feed and lay eggs into the fall on kudzu and other hosts.
As temperatures and day length decline, kudzu bugs seek out sheltered areas where they can pass the winter, such as under bark or rocks, or in leaf litter, etc. As they encroach on kudzu patches and soybean fields near residential areas, we can expect to see them invade homes similar to the behavior of another nuisance pest, the Asian lady beetle.
The bugs will often congregate on light-colored surfaces (such as siding, fascia boards, etc.). They will then move under siding, or into gaps around doors and windows, or through penetrations such as around air conditioning and water pipes.
In the following spring, the bugs become active again and begin moving onto kudzu and other host plants. As results, those bugs that have overwintered inside homes (inside walls, attics, etc.) may end up inside the home instead of heading to food sources.
Kudzu bug control
Homes near soybean fields or patches of kudzu are more likely to be invaded by the kudzu bug. Residents should start watching for signs of the bugs’ movement around the end of September, particularly in areas where temperatures start declining.
Although most common household insecticides will kill the bugs on direct contact, control of the kudzu bug by treating the exterior of homes is likely to produce poor to mediocre results for several reasons.
First, most residents do not have the proper equipment to apply an insecticide to areas high up on their homes where the bugs may congregate. Second, because the insects are actively feeding even in the fall, their movement out of these plantings may take place over several weeks which means several applications (e.g., weekly) may be need to try to reduce their numbers.
Wettable powder formulations of insecticides may produce better results (although they will still not prevent the bugs from invading homes).
When using insecticides, always read and follow the directions for use on the product label. Exercise extreme caution when spraying overhead since chemical will likely drop down on you and objects around you. Wear protective clothing and equipment (gloves, goggles, etc.) to keep the insecticide off of you. Be sure to remove or cover objects such as outdoor chairs, grills, and children’s toys.
Pesticides have limited ability to stop the bugs from entering homes, so it is also important to seal gaps and openings (such as around plumbing and AC lines) to prevent the bugs from entering home. Avoid crushing insects that do find their way indoors, as this may stain surfaces and/or result in unpleasant odors.
Vacuum up the insects and then place the vacuum bag (or contents) into a trash bag and freeze the bag for several days. You can also drop the bugs into soapy water to kill them. If you simply dump the live insects outdoors, they will likely end up back inside or surviving somewhere else around your property.
Removing kudzu patches in neighboring areas can be helpful but may be difficult unless you get cooperation from the property owner.
Treating kudzu for the bugs is difficult without the proper equipment and care must be exercised to make sure the pesticides do not run off into sensitive areas such as wetlands, creeks, etc. The insects are fairly mobile (they crawl and fly) and so even eradicating (or attempting to eradicate) kudzu in or near your yard may not solve the problem.
Thanks to Michael Waldvogel and Patricia Alder, Entomology Extension.
Susan Brown is a horticulture agent with the Brunswick County Extension Service. Call 253-2610 or e-mail email@example.com.