There’s a new kid on the block in the insect world around here called the kudzu beetle.
When disturbed, these ladybug-sized critters emit a caustic chemical that smells bad and can raise welts on people. The substance can cause a stain when the bugs are squashed.
Don’t be surprised to find kudzu bugs on the eastern side of your house, especially if it’s white or some other light color and you live near a patch of kudzu.
The only good thing about kudzu beetles is that kudzu plants are their favorite food in Japan, where they both originated, and in the United States.
The ideal scenario would be for kudzu beetles to eat kudzu and themselves out of existence, but that’s unlikely since kudzu grows even more prolifically in the southern United States than in Japan.
Soybeans have turned out to be a favorite food of kudzu beetles in the United States, even though they don’t feed on it in Japan.
Instead of chewing on plants, kudzu beetles suck moisture and nutrients from stems and leaves with “piercing-sucking mouthparts.” This can stunt growth while not actually killing plants. Research is continuing to determine by how much it reduces soybean yield.
The threat to soybean production, worth $500 million alone in North Carolina, is driving research on how to control kudzu beetles at North Carolina State University, Clemson University and elsewhere.
They reproduce twice a year – in the spring or early summer and then in late summer.
One of the notable things about kudzu beetles is that bacteria they transfer from one generation to the next in their eggs tells the young what to eat, which in the United States includes soybeans.
Researchers are trying to find a way to manipulate the bacteria, which apparently is placed in eggs, to trick kudzu bugs into not eating soybeans. They also are experimenting with a wasp from Japan whose larvae attack the kudzu bug embryos.
Chemicals exuded by kudzu beetles apparently tell them where to congregate, which explains why thick swarms may be found on one plant and none on the adjacent plant.
Since first noticed in nine northeast Georgia counties flying from patches of kudzu to the outside walls of nearby houses and structures in October 2009, kudzu beetles have spread rapidly into the Carolinas and other Southern states.
Kudzu beetles are noticed as a nuisance primarily twice a year: in March and early April as they emerge from winter inactivity in search of kudzu and in mid-October to early December as they move from host plants to over-wintering sites.
They also feed on wisteria and congregate (while not feeding) on certain other plants, including fig and magnolia trees, crepe myrtles, grapes, wheat, cotton and corn.
The United Soybean Board and the South Carolina Soybean Board helped sponsor a national conference on kudzu beetles in September at Clemson University.
Attendees discussed how different varieties of soybeans hold up to the bug, what insecticides and bio-control methods work best and how yields in infected soybean fields vary depending on planting dates and maturity groups.
Scientists have come up with insecticides that kill swarms effectively, but timing pesticide sprays is tricky and can be costly.
The overwhelming numbers of insects combined with nearby sources of re-infestation can make control difficult. Ultimately, kudzu needs to be removed with herbicides or other means to get rid of kudzu beetles.
A good website with more information is at http://www.kudzubug.org.