What is in this article?:
• The one good thing that can be said about the kudzu bug is that it usually doesn’t feed on pods — it’s primarily a stem feeder.
• The type of yield loss depends on when the bugs put enough stress on the plant to cause yield loss.
• It can be a very serious pest if left uncontrolled.
THE KUDZU BUG is a relatively new insect pest in Southeast soybeans, but it can cause significant yield reductions if not treated.
Georgia soybean producers made a record crop this past year with 37 bushels per acre, but yields might be improved even more by controlling insect pests like the relatively new kudzu bug.
This pest was first observed in the United States in the fall of 2009, in northeast Georgia,” says Phillip Roberts, University of Georgia Extension entomologist.
“Now it’s easy to find — if you grow soybeans in Georgia, you’ve probably seen it, and you’ve probably seen a lot of differences among populations in your fields,” said Roberts at the 2013 Georgia/Florida Soybean/Small Grain Expo in Perry, Ga.
It is a “true” bug, he says, with a sucking mouth part. “Both adults and immatures will use that sucking, piercing mouth part to feed on a plant. They feed primarily on the main stem, and they also feed on petioles. The adults have a hard shell and the immatures are soft and almost fuzzy in appearance,” says Roberts.
The one good thing that can be said about the kudzu bug is that it usually doesn’t feed on pods — it’s primarily a stem feeder, he says.
“If this insect fed on pods, like stink bugs, we probably would not be growing soybeans. It would be very intensive in terms of management with insecticides. I like to think of it as a stress-inducing plant — it just adds more stress to the plant.”
In the past three years, Roberts and other researchers have learned the kudzu bug impacts soybean yield in three ways: it can reduce the number of pods set on the plant, it can reduce the number of seed set in the pod, and it can impact the size of the seed and affect how the bean itself actually sizes up.
The type of yield loss, he says, depends on when the bugs put enough stress on the plant to cause yield loss.
“Over the last three years, we’ve conducted a lot of different trials on this insect in soybeans. On average, we’ve observed about a 20-percent yield loss in untreated plots compared to where we treated for the insect. We’ve seen a range of yield loss from zero up to 60 percent. It can be a very serious pest if left uncontrolled,” says Roberts.
The kudzu bug initially was found between Athens and Atlanta, he says. To date, it has been observed in every county in Georgia with the exception of Camden County.
“No soybeans are produced in that particular county, and we could not find any kudzu. It was observed in 2012 in the Florida Panhandle. If you’re from north Florida, history has shown us that once the insect is detected, you can expect economic damage the very next year.