DESCRIPTION OF 3 ISOZYME POLYMORPHISMS ASSOCIATED WITH INSECTICIDE RESISTANCE IN GREENBUG (HOMOPTERA, APHIDIDAE) POPULATIONS

Esterases have been associated with insecticide resistance in several aphid species. This report documents existence of 3 esterase polymorph isms associated with insecticide resistance in the greenbug, Schizaphi s graminum (Rondani). Esterases were resolved using polyacrylamide gel electrophoresis and R(f) values were calculated for the 6 esterase ba nds that resolved. The 3 esterase polymorphisms observed have been nam ed no noticeable elevated esterase, pattern 1 and pattern 2. Esterase bands visible on the polyacrylamide gel appear to have no elevated act ivity in the no noticeable elevated esterase strain. A single esterase band appears to be elevated in pattern 1 individuals and 3 esterase b ands appear to be elevated in pattern 2. After testing >10,000 greenbu gs, no individual greenbug has been detected with both pattern 1 and p attern 2 banding. It is unknown whether the 2 elevated esterase forms es or isozymes. Surface-residue bioassay data are presented that suppo rt the hypothesis that these elevated esterases may be important in in secticide resistance.