STATUS OF THE DISTRIBUTION OF KUDZU BUG IN ALABAMA
The kudzu bug has been “officially” reported to occur in 53 of Alabama’s 67 counties as of June 27. Last year in the first week of June this invasive species had been reported in 15 counties. It is quite likely that this insect is now present in all Alabama counties. Several counties have reported significant populations of kudzu bugs infesting soybeans during June in Alabama in 2013 and numerous fields have been sprayed.
LIFE CYCLE AND HOSTS OF THE KUDZU BUG
The time required for the kudzu bug to develop from an egg to the adult stage is 6 to 8 weeks. The egg hatches in about 5 days. The kudzu bug has been found on many plants but presently the only host plants on which it is known to reproduce are kudzu, soybean and wisteria.
ECONOMIC THRESHOLDS FOR KUDZU BUG ON SOYBEAN
Thresholds for kudzu bugs infesting soybeans continue to evolve as more information is gained from research efforts. Southeastern entomologists are currently recommending that growers consider using the following thresholds when making kudzu bug treatment decisions: 5 bugs per seedling, until plants are one foot tall. Then, the threshold will change to 10 bugs per plant for plants from 1-2 feet tall. The established threshold of one nymph per sweep should be used for plants above 2 feet tall. Plants should be sampled at least 50 feet from the edge of the field.
The reason for this is that the adults have an extended migration period (6-8 weeks) and colonize field edges first. If you sample the edges, chances are you will make a spray decision too soon before the migration is over.
WHICH CHEMICALS ARE EFFECTIVE IN CONTROLLING KUDZU BUG IN SOYBEANS
Multiple classes of insecticides have shown activity on kudzu bugs. Insecticide treatments containing bifenthrin, cyhalothrin, zetacypermethrin, carbaryl, or acephate provided greater than 80 percent control 2-5 days after treatment in insecticide efficacy trials conducted in Georgia and South Carolina. Insecticides do not prevent eggs from hatching. Growers actively treating kudzu bugs with broad spectrum insecticides should consider using a preventive application of Dimilin (2 oz/acre rate) at the R2/R3 growth stage for control of velvetbean caterpillars and green cloverworms in July, especially in central and south Alabama which historically have had higher populations of velvetbean caterpillars than north Alabama.
EFFECT OF PLANTING DATE ON KUDZU BUG POPULATIONS IN SOYBEANS
Studies in Georgia and South Carolina have shown that kudzu bug populations are higher on earlier planted soybeans than on later-planted beans.
Tim Reed, Extension Entomologist, Auburn University