Artificial substrate bioassay for testing oviposition of southern green stink bug conditioned by soybean plant chemical extracts

A laboratory bioassay was developed for testing oviposition preference of southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), toward chemicals extracted from soybean, Clycine max (L.) Merrill, pods and leaves. In this bioassay, an artificial substrate (cheesecloth) was stretched over a wooden ring (embroidery hoops), treated with plant extracts or chromatographic fractions, and then exposed to adult stink bugs to assess oviposition preference. The methanol extract of pods stimulated the greatest oviposition. After a chromatographic separation on a reverse phase open column, the most active fraction derived from this extract was that eluted with 20 methanol in water. After subjecting this fraction to chromatography on silica, the greatest activity occurred in the fraction eluted with 60 methanol in methylene chloride. Further fractionation of this material by thin layer chromatography gave no single fraction with demonstrated activity, but the recombined fractions were again active, indicating that multiple components are probably involved in eliciting oviposition. Antennectomized females did not differentiate treated versus untreated substrates, but females with the hairs of the genitalia coated did, indicating that the oviposition-eliciting compounds were sensed by the antennae, rather than by hairs of the genital plaques. Made available in DSpace on 2022-04-11T19:01:48Z (GMT). No. of bitstreams: 1 ID-24750.pdf: 5687162 bytes, checksum: edd6e49bf942f318e01a593dcf7611b3 (MD5) Previous issue date: 2004