Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 21, 2001
Publication Date: N/A
Interpretive Summary: The diamondback moth is the most widely distributed of all the Lepidoptera, and is the most destructive pest of cruciferous crops throughout the world. An estimated one billion U.S. dollars or more is spent on the control of diamondback moth annually. Chemical control has been relied on extensively for suppression of DBM populations, but it has become resistant to virtually all groups of chemical pesticides. Mating disruption using sex pheromone is a proven control strategy for this pest, but the technology for applying the pheromone has not been accepted by growers because the product is expensive, labor intensive to apply, and may interfere with cultivation and fertilization procedures. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, Florida, evaluated a novel, new system for delivering pheromone to control the diamondback moth in cabbage. The liquid, viscous slow release formulation contained a combination of diamondback moth sex pheromone and a small quantity of insecticide. Small field plots treated with the pheromone- toxicant material suppressed sexual communication by diamondback moth >90% up to three weeks. The results indicate that the material, trade name Last Call DBM, possibly could be used to suppress mating by diamondback moth pest in cabbage and other crucifers although as many as three applications probably would be required for suppression over an entire growing season. The new formulation offers an alternative to present technology for delivering pheromones to control diamondback moth without the constraints of present systems at possibly lower cost.
Technical Abstract: Experiments were conducted in cabbage in spring 1999 and 2000 to evaluate a novel, new matrix system for delivering sex pheromone to suppress sexual communication by diamondback moth (DBM), Plutella xylostella (L.). The liquid, viscous slow release formulation contained a combination of diamondback moth pheromone, a blend of Z-11-hexadecenyl acetate, 27%:Z-11- hexadecen-1-ol, 1%:Z-11-tetradecen-1-ol, 9%:Z-11-hexadecenal, 63%, and the insecticide permethrin (0.16% and 6% w/w of total formulated material, respectively). Field trapping experiments showed that the lure-toxicant combination was highly attractive to male moths for at least 4 weeks using as little as a 0.05 g droplet of material per trap; and the permethrin insecticide had no apparent influence on response of moths to lure baited traps. Small field plots were treated with the lure-toxicant-matrix combination using droplets of 0.44 and 0.05 g ea applied to cabbage in a grid pattern at densities ranging from 990 to 4,396 droplets/ha to evaluat the potential for disrupting sexual communication of DBM. There was no significant difference in the level of suppression of sexual communication of DBM among the treatments regardless of droplet size or number of droplets applied per ha. Plots treated with the smallest droplet size and with the fewest number of droplets suppressed captures of male DBM >90% for up to 3 weeks post treatment. Although lab assays showed that the lure- toxicant combination was 100% effective at killing the DBM, the mode of action in the field was not determined. The results indicate that the formulation containing DBM pheromone could be used to suppress sexual communication of this pest in cabbage and other crucifers although as many as 3 applications may be required for suppression over a growing season.