Be on the lookout
The kudzu bug is about the size of a pea, is metallic brown and has a broad butt. It is closely related to stink bugs and will emit an offensive odor if annoyed or squished.
Like other true bugs, kudzu bugs insert straw-like stylets into plants to suck out the phloem—the plant’s nutrient-carrying liquid.
Most of what entomologists know about the kudzu bugs’ habits in this country is based on observations and on field trials in soybeans.
As a result of feeding on stems and leaves, soybean plants are weakened, causing wilt, defoliation, reduced pod set and reduced bean size. It doesn’t appear to feed on bean pods.
“What we’re generally seeing is they like to feed on the stems,” Gardner says. “If they’re on the leaves, I think they’re feeding on the veins of the leaves.”
Last year in untreated Georgia soybean fields, kudzu bugs caused 10 percent to 30 percent yield reductions, Sparks says.
“And they’re running into populations that are higher than they were last year,” he says. “One of my big concerns is contamination at harvest.”
The good news is that several registered pesticides, including pyrethroids, control the pest, Sparks says.
Pests on the move
One of the challenges is the pest’s migratory nature, Gardner says. You can treat your fields, significantly reducing populations.
But adults simply move in from untreated adjacent kudzu and reinfest your crop.
As the kudzu begins to senesce and die off in October, kudzu bugs seek overwintering shelter in large groups. This can include under tree bark, in wood piles, in plant litter in fields and in houses, Gardner says.
In fact, homeowners in northeast Atlanta first brought the pest to entomologists’ attention in 2009, he says.
“Homeowners were complaining about these bugs all over their houses,” he says.
When the kudzu begins to sprout in spring, kudzu bugs emerge from overwintering and begin laying eggs, starting the cycle again.
Kudzu bug added to survey list
Surveyors who are part of the national Cooperative Agricultural Pest Survey have added the kudzu bug to their list of pests to watch for when they’re out in the field, Hodges says.
In addition, DPI and the University of Florida twice a year conduct a joint pest videoconference to exchange information and update each other on the latest findings.