Field evaluation of gossyplure, the synthetic sex pheromone of Pectinophora gossypiella (saund.) (Lepidoptera, Gelechiidae) in Malawi

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Abstract
The synthetic sex attractant of the pink bollworm of cotton, Pectinophora gossypiella (Saund.) (Lepidoptera, Gelechiidae), is a mixture of (Z, Z) and (Z, E)-7, 11-hexadecadien-l-ol acetate, referred to as gossyplure (Hummel et al., 1973). Field trials in the Lower Shire Valley, Malawi, have shown that of various mixtures tested, 55–60% of the (Z,Z) isomer in a mixture of the two acetates gives maximum field attraction. The catches of both pink bollworm males and males of the red bollworm of cotton, Diparopsis castanea Hmps., in pheromone traps are not affected by the release of mixtures of the pheromones of both species together. Dual-purpose sex pheromone traps may therefore be used to monitor both pest species at the same time. A simple omnidirectional flat disc trap is as efficient in trapping pink bollworm males as more complex designs. Release of gossyplure from a sealed 2·5 ml polyethylene vial or from a Zoecon beem-polyethylene vial is more efficient than from narrow-bore teflon capillary. Presence of the antioxidant 2,6-di-tert-butyl-P-cresol at 8·4% w/w gossyplure does not increase the attractive life of the pheromone in the field. Considerable numbers of the Angoumois grain moth Sitotroga cerealella (Ol.) (Tineidae), together with a new species of gelechiid, were occasionally caught by gossyplure lures in cotton fields. Catches of pink bollworm are not influenced by moonlight or trap colour but are significantly influenced by trap area. Maximum catches of males occur between midnight and 04.00 h in June and between 01.00 and 05.00 h in August.