What is in this article?:
- Kudzu bugs cut yields in unsprayed soybeans
- Official treatment recommendations
- While there’s still some debate over whether or not the most recent harsh winter reduced kudzu bug numbers, there seems to be full agreement that there were enough of the insect pests in 2013 to damage soybean yields in Alabama, and there will probably be enough again this year.
AN ESTIMATED 10,000 acres of soybeans were sprayed for kudzu bugs in Alabama in 2013, mainly in the east and east-central areas of the state.
Official treatment recommendations
The Alabama Cooperative Extension System’s economic threshold for kudzu bugs in soybeans this year, he says, call for treating prior to first bloom when there is an average of five kudzu bugs per plant for the entire field.
“After first bloom through R6, apply an insecticide when a sweep-net sampling catches 10 adults per sweep or one nymph per sweep. When using a sweep net, a sweep is defined as one sweep across two rows using a 15-inch diameter sweep net.,” says Reed. “If immature kudzu bugs are easily and repeatedly found on petioles and main stems during visual inspections of the canopy, treatment is likely warranted.”
He advises that growers should not limit all sampling to border rows where populations build initially.
“Border treatments in some cases have slowed the movement of adults across fields. If immature kudzu bugs are easily and repeatedly found on petioles and main stems during visual inspections of the canopy, treatment is likely warranted,” he says.
Retreatment may be necessary when a treatment is applied before migration into soybeans stops, says Reed, and growers should be aware that spraying for kudzu bugs will significantly reduce beneficial insects, which could result in economic infestations of caterpillars.
This threshold, he says, is based on one year’s experience and will be adjusted as more research is conducted and experience is accrued. “Due to the tendency of this pest to congregate on the field borders, initially it is important that growers use an average population estimate for whole fields before making a whole-field insecticide application.”