The kudzu bug, scientifically known as Megacopta cribraria, is a new pest in South Carolina. It is not a beetle, as many people think, but is more closely related to stink bugs. It has also been called a bean plataspid due to its insect family name: Plataspidae. Kudzu bugs were first detected in northeastern Georgia during October 2009. They are now spread throughout Georgia, South Carolina, and other southern states.
Adults of the kudzu bug are about the same size as adult lady beetles and are small, almost square-appearing insects, approximately ¼ inch long; light brown with an olive-green hue (Figure 1). The immature stages are similarly shaped but smaller and very “hairy” in appearance (Figure 2). Eggs of kudzu bugs (Figure 3) are a light tan color, barrel-shaped, and often placed on plant leaves in two rows.
Depending on temperature, it takes approximately 6 weeks for a kudzu bug to go from an egg to an adult. Current research has found that there are two generations of kudzu bugs in the southeastern United States each year. Much of the kudzu bug populations develop on kudzu or wisteria for the first complete generation, and the second generation completes its development on soybeans and other cultivated and wild hosts (kudzu, wisteria, etc., included). Overall, second generation kudzu bugs have a preference for bean related plants.
Kudzu bugs feed on kudzu and on many other plants such as wisteria, soybeans, and most any bean plant. Some types of wisteria are invasive plants from the same region of the world as kudzu. In the fall, large numbers of kudzu bugs will move from plants to sheltered areas to overwinter.
Many overwintering sites include leaf-litter and crevices on trees or shrubs. Unfortunately, many of the protected places they also seek are cracks, crevices, and voids around homes and other buildings. Research has found that they prefer light colors on houses, particularly white. Kudzu bugs are often observed around window trim, doorframes, gutters, and sunlit areas that are often brightly colored (Figure 4).
During the spring, kudzu bugs become active again and move from their sheltered areas to search for suitable host plants for feeding and reproduction. They are often observed aggregating on numerous kinds of plants during the spring while waiting for their preferred hosts to leaf-out.
Large numbers of kudzu bugs are a nuisance in and around structures. Their body secretions produce a foul odor and can stain fabrics and wall coverings. Directly handling kudzu bugs can cause staining of the skin and even blistering and moderate discomfort in some sensitive individuals.
In the fall, large numbers of kudzu bugs will move from kudzu and other plants to find sheltered locations for overwintering. Cutting back kudzu patches or even other plants such as wisteria that can be removed before the fall should help reduce kudzu bugs around the home. Kudzu bugs are good fliers, so they may move to a house or structure from plants outside of the property area.
Sealing as many cracks and crevices as possible on structures will help prevent kudzu bugs from entering structures. Screens will also help prevent kudzu bug entry. It is important to make sure soffit vents and peak vents on homes have good screening in addition to window and door screening.
Large numbers of kudzu bugs found indoors should be vacuumed, not sprayed. Avoid crushing them to prevent their body secretions from staining fabrics or wall coverings. If possible, use a shop vacuum rather than a conventional vacuum. Kudzu bug odor may linger in a conventional vacuum. A shop vacuum with some soapy water (1 to 2 tablespoons of dish soap per gallon of water) in the canister will kill the bugs. After use, the soapy water should be discarded. If a regular vacuum with a bag is used, discard the bag after vacuuming.
Most insecticides available to homeowners will kill kudzu bugs. If you are spraying vegetation, make sure you use a product that is labeled for treating plants. If you spray your home, make sure you use a product that is labeled for structural use. Spray outdoor surfaces where kudzu bugs are likely to land, or directly spray bugs on your house before they move into recessed areas. Try to limit your sprays to small-targeted areas. In the fall, spray during daylight when nighttime temperatures begin to cool, around 50o F or cooler. This will provide fresh materials to kill the bugs while they are active (during the day). Rain and direct sunlight will degrade treatments in open areas, so reapplications may be needed.
If you do spray and kill large numbers of kudzu bugs, try to remove them, especially in indoor locations. Large numbers of bugs can produce a foul odor over time and attract secondary pests such as carpet beetles and ants. In the spring, kudzu bugs move from structures back to plants. It may be best to let them go without spraying. If they need to be sprayed, try to treat them directly on sunny, cool mornings before they become active.
If control measures seem complicated, or if kudzu bug numbers are very high and continue to reinvade your home, consider hiring a pest management professional. If you do your own chemical control, make sure you follow all label directions.
Clemson University is doing research to produce more information on kudzu bugs and their control. Check for revised fact sheets or other materials as new research information becomes available. For more information on kudzu bugs, visit Regulatory Services‘ website.