Received for publication 24 Aug. 1984. The investigation reported in the paper (84-10-143) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with approval of the Director. This material is based on work supported, in part, by the USDA, Agreement No. 59-2213-1-1-717-0 (Competitive Research Grants Program). The authors gratefully acknowledge Douglas Dahlman, Dept. of Entomology, for supplying insects and reviewing the manuscript.The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.