Thursday, October 20, 2011

Kudzu Bug - A Small, Brown, "Lady Bug" That Invades Homes and Gardens

Kudzu bugs clustered on wisteria. Photo by Julie W.
If you live in the south-eastern US you may have noticed a new insect this summer and fall (see photo): the insect is called the kudzu bug (Megacopta cribraria) and is characterized by -
  • small, brownish/green in color
  • shaped sort-of like a ladybug
  • not seen prior to about 2 years ago
  • invades homes in the fall
  • congregates on garden plants, and especially, kudzu vine (For those that don't live in the southern US, kudzu is a highly invasive weedy vine, "the vine that ate the south!", that grows everywhere, on everything.)
  • a new and important pest of soybean
    This true bug (Hemiptera)  resembles a ladybug (a cocinellid beetle) in size and shape, but not color (see this page for a picture of a real ladybug/lady beetle). Also, you don't generally find ladybugs clustered together like you see in the photo.

    This a new "lady bug" has some unpleasant characteristics. (1) Feeds on and weakens garden plants as well as some agricultural crops, like soybean, in addition to weedy plants like kudzu; (2) produces a distinctive, strong odour when disturbed; (3) congregates on houses in the fall when air temperatures start to drop. This final characteristic of "invading" homes in the fall is the one that many people will notice first.

    The kudzu bug was first found in north-eastern Georgia in 2009 but has since spread to North Carolina, South Carolina, Alabama and will likely spread to all south-eastern states in time, anywhere kudzu grows.

    Kudzu bugs as nuisance pests

    Because the kudzu bug arrived in North America without the natural enemies that would normally keep populations in check in their native lands (Asia), this bug has seen explosive growth. After feeding and multiplying all summer the population of kudzu bugs in an area can be large. Then as the air temperatures begin to decline in fall these bugs move from their host plants and seek shelter for winter months. They often congregate on houses just like similar bugs such as the brown marmorated stink bug of the northeastern US and the boxelder bug. And, like these others kudzu bugs are harmless to people and homes but can be a significant nuisance to homeowners when they congregate on siding, and enter walls and attic spaces.

    What should you do?

    Treat kudzu bug invasions like you would boxelder bugs or brown marmorated stink bugs - see How to Manage Boxelder Bug Invasions for details. Eventually the numbers of kudzu bug will decline as native predators and parasites discover this new insect and adapt to it. Until then, at least it is impacting the growth of kudzu vine!