Keep eyes peeled for building kudzu bug numbers in Arkansas

kudzu bug
A fifth instar kuzu bug numph — Photo courtesy University of Arkansas

Kudzu bugs have been detected on kudzu in several Arkansas counties, prompting a warning to scout and only treat if economic thresholds are reached.

The pest was first detected in Arkansas in 2013, and populations have been building since. In 2015, they were found in soybean fields but in non-damaging numbers.

But 2016 could be a different story.

“We’re expecting to see damaging levels this year,” Gus Lorenz, University of Arkansas Extension entomologist, said in a news release. “Last year, they never rose to the treatment threshold, but this year, we’re seeing them a lot more frequently, and they’re increasingly moving from kudzu to soybeans as they seek a new host.”

Kudzu bugs are true bugs. Adults are olive green to brown with a box-like shape. They may resemble bean beetles or ladybird beedles, but they have more of a hump.

Newly hatched numphs are orange and about the size of a pinhead. Older nymphs are green, oval-shaped and hairy. Kudzu bugs have an incomplete metamorphis, meaning the nymphs somewhat resemble adults.

Kudzu bugs suck the sap from stems of kudzu, soybeans and other related legumes.

Of those, soybeans are the most important host, and large numbers of immature kudzu bugs can cause yield losses. The treatment threshold is one nymph per sweep.

Pyrehroids are labled for kudzu bugs, but Lorenz warned that growers should make a treatment until the insects reach thresholds.

“If you treat them as soon as you find a single nymph in an entire field, you’ll just have to go out and treat them again,” Lorenz said. “When you treat with pyrethoids, you open the door for other pests, because you’re also killing all the beneficial insects. With this particular bug, you just want to wait.”

Kudzu bugs also may congregate on wisteria and some edible beans, but nymphs don’t survive well on these plants.

Read more about kudzu bugs in this fact sheet.

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