Author
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Mitchell, Everett |
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Mayer, Marion |
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Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/26/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Traps baited with insect pheromone lures have been used to monitor seasonal fluctuations in adult crop pest, to time applications of insecticides and to measure the efficacy of disruptive pheromone treatments. As useful as trapping is for some insects, however, the corn earworm moth is not so easily captured in traps other than large cones made from screen wire. Cone traps are expensive, time consuming to service and often get in the way of normal farming practices. What is needed is further understanding of lure composition and how it affects trap captures. Scientists at the Center for Medical, Agricultural and Veterinary Entomology, Gainesville, FL, have developed a simple, rapid and inexpensive method to measure the release of components from pheromone-emitting dispensers. This technology was used to measure the volatile emissions of corn earworm sex pheromone components from several different commercially formulated lures. Volatile emissions from the lures were analyzed by gas chromatographic methods and the numbers of males captured in cone and bucket traps were compared with bait emissions. The Hercon lure captured the same number of males in both types of trap; whereas, the other lures tested either captured no moths or captured moths in either buckets or cones but not both types of trap. The effectiveness of the Hercon lure was associated with lower emission rates for (Z)-ll-hexadecenal and (Z)-9-hexadecenal compared to other lures. This technology will allow for more effective lure formulations that can be used in less costly and smaller traps, e.g. bucket traps, that are easier to service and less disruptive to normal cultural practices. Improved formulations also should improve assessment of efficiencies in monitoring adult pest populations and mating disruption technology. Technical Abstract: Captures of male corn earworm moths, Helicoverpa zea (Boddie), were compared in conical Texas pheromone traps (cone trap) and bucket traps baited with commercial baits from three different manufacturers. The volatile emissions from the lures were analyzed by gas chromatographic methods and the numbers of males captured in the two types of trap were compared with the bait emissions. The lure from one manufacturer, Hercon, captured the same numbers of males in both types of trap. One lure effected as many captures in bucket traps as the Hercon lure, but effected fewer captures in cone traps. The effectiveness of the Hercon lure was associated with a lower emission rate of (Z)-11-hexadecenal and (Z)-9-hexadecenal than the other lures. A gas-liquid chromatographic peak associated with a third compound, (Z)-9-tetradecenal, which is reputed to reduce behavioral responses, was observed in the emissions from all the lures evaluated. |
