What is in this article?:
- A new pest for Mississippi soybean growers and homeowners: the kudzu bug
- Detailed information from Georgia
Although the kudzu bug, a new invasive pest now confirmed in Mississippi, can cause soybean losses when populations are large, the insect can be easily controlled, says Angus Catchot, Mississippi State University Extension professor of entomology and plant pathology. "When this pest becomes established, our high management growers probably won't need to add a spray to those they're already using," he says.
THE KUDZU BUG. The pest has been confirmed at several locations in Mississippi. —Photo by Tom Allen
Detailed information from Georgia
The following information on the kudzu bug is from the 2012 Georgia Soybean Production Guide.
Adult kudzu bugs are oval shaped, about ¼ inch in diameter, and greenish brown in color. Eggs are laid in double-rowed batches of 35-50 eggs and are white in color.
Nymphs are also oval-shaped and are light green to brown in color and have numerous setae/hairs. Both adults and nymphs are most commonly seen on plant stems using their sucking mouthparts to feed on plant sap.
The effects of kudzu bug feeding on soybeans are similar to drought. Excessive feeding weakens and stresses the plant, which can result in fewer pods per plant, fewer seeds per pod, and reduced seed size.
Over-wintering adults survive under pine bark and ground debris. Key reproductive hosts of kudzu bugs include kudzu, wisteria, clover and soybeans.
Adults begin laying eggs on kudzu shoots in mid-April and continue laying eggs on kudzu for several weeks.
Time required to reach the adult stage is about 6-8 weeks. These new adults then disperse to soybeans and other reproductive hosts beginning in mid-June and continuing through mid-July.
Soybeans become attractive to kudzu bug adults when plants are 8-10 inches tall. Early planted soybeans appear to be at greater risk for kudzu bug infestation compared with later planted soybeans.
Adults will begin laying eggs on the underside of soybean leaves and a generation requiring about 6 weeks will be completed on soybeans.
Initial field invasions tend to be more concentrated on field margins, but will eventually spread throughout the field. In many situations we will begin to see immature kudzu bugs in soybeans at about the R2-R3 stage.
Kudzu bugs can be scouted using a 15-inch diameter sweep net.
Kudzu bug populations can be extremely high. Georgia entomologists are suggesting a threshold of one immature kudzu bug per sweep. This suggested threshold is based on 2011 field trials where a single properly timed insecticide application preserved soybean yield.
If insecticides are applied when adults are still actively migrating from kudzu to soybeans (late June and early-mid July); additional applications may be needed.
Research is ongoing to verify and refine management and treatment thresholds for kudzu bugs in soybeans.
Multiple classes of insecticides have shown activity on kudzu bugs. Insecticide treatments containing bifenthrin, cyhalothrin, zeta-cypermethrin, carbaryl, or acephate provided greater than 80 percent control 2-5 days after treatment.