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United States Department of Agriculture

Agricultural Research Service


item Pare, Paul
item Alborn, Hans
item Tumlinson Iii, James

Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: When beet armyworm caterpillars chew on corn or cotton leaves the plants emit an odor that attracts natural enemies of the caterpillar pests. These natural enemies, which parasitize the caterpillars, are effective biological control agents. A chemical called volicitin, from the oral secretions of beet armyworm caterpillars, that triggers the plant biochemical mechanisms to produce and emit the attractive odors has been identified and synthesized. Scientists at the Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, have discovered that the caterpillars modify plant derived chemicals to produce volicitin. Ironically, these caterpillar modifications are critical to producing the biologically active chemical that triggers the release of plant volatiles, which in turn attract the natural enemies of the caterpillars. This discovery makes it possible to determine the biochemical enzymes and genetic processes in both the plant and the caterpillar that are activated in this process. With this knowledge it should be possible to develop plants that, when attacked by insect pests, become highly attractive to natural enemies of those pests. This will significantly enhance the effectiveness of biological control methods with insect natural enemies.

Technical Abstract: The elicitor of plant volatiles, N-(17-hydroxylinolenoyl)-L-glutamine, named volicitin and isolated from beet armyworm caterpillars, is a key component in plant recognition of damage from insect herbivory. Analysis of the oral secretion from beet armyworms that have fed on 13C labeled corn-seedlings established that the fatty acid portion of volicitin is plant derived, whereas the 17-hydroxy and glutamine moieties are added by the caterpillar. Ironically, these insect catalyzed chemical modifications to linolenic acid are critical for the biological activity that triggers the release of plant volatiles, which in turn attract natural enemies of the caterpillar.

Last Modified: 06/23/2017
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