IMPORTANCE OF SAMPLING NYMPHS IN THE EVALUATION OF INSECTICIDES FOR THREECORNERED ALFALFA HOPPER (HOMOPTERA: MEMBRACIDAE) CONTROL

Results of field insecticide efficacy studies for control of the threecornered alfalfa hopper, Spissistilus festinus (Say), in soybean, Glycine max (L.) Merrill, indicated that sampling of nymphs allows for a more complete interpretation of efficacy test results than sampling of adults alone. Sampling of nymphs not only allows detection of activity against nymphs, but because of their relative immobility, it also allows better destinction between reinfestation versus development of populations within plots and better evaluation of residual activity. Of the insecticides evaluated, four pyrethroids (asana, cyfluthrin, cyhalothrin, and fenvalerate) and an insect growth regulator (buprofezin) were found to provide the best control.