Behavior of the Parasite Aphelinus asychis1 in Relation to the Greenbug 2 and Certain Hosts 3

Abstract

The green bug, Schizaphis graminum (Rondani), is a major pest of small grains and sorghum in central and western United States. Biotype C of the greenbug often causes severe sorghum loses. Because most cereals and sorghums are relatively low-value-per-acre crops and because of residue problems, control by resistant varieties, predators, and parasites is particularly desirable. Resistant varieties are promising (Harvey and Hackerott 1969) and several parasites, including Aphelinus asychis (Walker), have been introduced (Jackson and Eikenbary 1971). Some consider A. asychis synonymous with A. semiflavous; others think the two are separate species.