Determining pest status of threecornered alfalfa hopper, (Membracidae: Spissistilus festinus), in peanut (Fabaceae: Arachis hypogaea).

Threecornered alfalfa hopper (TCAH), Spissistilus festinus (Say) (Hemiptera: Membracidae), has long been an economic pest of soybean and alfalfa and has recently become common in peanut.   Spissistilus festinus feeds by forming girdles, caused by a series of lateral punctures around the stem.  These girdles can result in galls and the eventual pooling of photosynthates and nutrients that the insect feeds upon.  Though S. festinus is currently being treated as a pest in peanut, no economic thresholds are available for the insect in this crop. The purpose of this study was to generate data needed to establish an economic threshold for TCAH in peanut.  Spissistilus festinus were placed on caged peanut plants in field and greenhouse trials; treatment variables consisted of insect density and plant age. The number of stem girdles and pods was quantified and seed quality was measured in each treatment.