Various rates of two insecticides were tested for efficacy on threecornered alfalfa hopper and Empoasca sp. leafhoppers. Data were also collected for efficacy of insecticides on beneficial insects present. Hay quality samples were taken after baling. Both insecticides provided excellent control of threecornered alfalfa hopper, and Baythroid also controlled Empoasca sp.leafhoppers. Quality of hay was increased where threecornered alfalfa hoppers were controlled, although this control was for only eight days prior to cutting. A decrease in digestible hay protein was noted with increasing numbers of Empoasca sp. leafhoppers.

Furadan 4F was applied to alfalfa regrowth stubble following the first harvest of 1998 to examine treatment effects of alfalfa weevils, aphids, resultant plant growth, and threecornered alfalfa hoppers. Furadan 4F reduced larval numbers throughout the period that larvae were present (25 days after treatment). Little effect was noted for adult weevil numbers in field. Aphid numbers were also reduced by the treatment, and alfalfa stems in Furadan 4F plots were significantly taller at 21 days post treatment. Little, if any, effect from the Furadan 4F treatment was noted for adult threecornered alfalfa hopper populations during the five months following application.

A study was conducted in Mohave Valley to examine population dynamics, economic thresholds, and management strategies for potato leafhopper and treehopper (three cornered alfalfa hopper) in desert alfalfa. In 1998, three distinct peaks of adult treehoppers occurred in August, September, and October. Adult potato leafhoppers were detected earlier in the study, with four distinct peaks noted in June, July, August, and September. Spring Furadan alfalfa stubble treatment reduced initial adult treehopper infestation following application by 40-60% and the initial potato leafhopper infestation was reduced by 25-50 %.