Tiny wasp is reducing kudzu bug populations in the Southeast

parasitoid wasp lays eggs on kudzu bug eggs
Parasitoid wasps lay their eggs on a kudzu bug egg mass — photo courtesy University of Georgia

A tiny wasp — known as Paratelenomus saccharalis — is reducing kudzu bug populations and Georgia soybean farmers’ need to treat for the pest, says Michael Toews, a University of Georgia entomologist based on the UGA Tifton campus.

The wasp, an egg parasitoid and natural enemy of the kudzu bug, is saving soybean farmers time and money.

“Growers used to spray multiple times during the season, and sometimes it would do nothing to suppress the kudzu bug population,” Toews says. “Now, they just let the wasps maintain the natural balance.”

During research trials, Toews and other UGA College of Agricultural and Environmental Sciences entomologists found that the insect recently appeared in commercial soybean fields.

“There’s no manipulation or manual placement,” Toews says. “The wasps naturally find any place that is infested with kudzu bugs. We found this wasp in every field that we examined in south Georgia.”

Kudzu bugs arrived in the United States in 2009 and quickly spread to more than 13 states across the Southeastern U.S., devastating soybean fields. The wasp was first detected in the United States in 2013, far from its origins in China, India and Japan.

Toews says this natural enemy became Georgia soybean farmers’ saving grace. The kudzu bug is a major pest to commercial soybeans, causing yield losses as high as 60 percent. High populations of the pest can damage soybean’s growth, seed weight and seeds per pod.

“Growers were really struggling, and yield losses were significantly cutting into profit margins,” he says. “There were some general natural enemies, but the wasp clearly evolved with the kudzu bug to manage this pest.”

Growers were using insecticides to control the kudzu bug, but those proved to have side effects

“When growers spray an insecticide, the insecticide can have detrimental effects beyond the target insect population,” Toews says. “They affect the balance of a lot of other things that weren’t pests before and upset the natural balance.”

Neither the kudzu bug nor the wasp were imported to the United States through formal efforts by the federal government or university scientists, he says. Both likely arrived through international commerce.

The wasp has now been reported in Georgia, Florida, South Carolina and Mississippi.

The University of Georgia contributed this article.

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