Author
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Light, Douglas |
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Submitted to: IOBC/WPRS Bulletin (Abstract for Conference Proceedings)
Publication Type: Proceedings Publication Acceptance Date: 12/18/2006 Publication Date: 11/15/2007 Citation: Light, D.M. 2007. Experimental use of the micro-encapsulated pear ester kairomone for control of codling moth, Cydia pomonella (L.), in walnuts.IOBC/WPRS Bulletin (Abstract for Conference Proceedings). 30(4):133-140. Interpretive Summary: Aspergillus invasion of tree nuts is primarily through insect damage by worm larvae, such as the codling moth (CM) attacking walnuts. Our goal is to diminish insect-caused nut damage through the use of novel, species-specific host-plant volatiles or kairomones. We have identified the pear ester (PE), as a powerful kairomone, attracting neonate CM larvae. We investigated using PE as an adjuvant to improve the use of insecticides. Food Quality Protection Act 1996 will soon restrict/ban use of organophosphate (OP) insecticides. Alternative insecticides must be made more effective and affordable. Because we found that neonate CM larvae are highly attracted to PE, we hypothesized that bait-sprays of kairomone + insecticide might attract - kill larvae more effectively. To test its efficacy as a larval bait-spray adjuvant, PE was micro-encapsulated (PE-MEC), tank-mixed with reduced rates of four insecticides (two OPs, an insect growth regulator and a virus) and sprayed on walnut trees. PE-MEC adjuvant reduced CM and navel orangeworm damage rates from 47% to 90% below rates incurred with insecticides alone. These studies show that the kairomone can attract and eliminate CM larvae, thereby decreasing damage and improving Aspergillus control. Since the PE increases rates of both crawling and turning, and stimulates orientation to PE by CM larvae, then PE-MEC applications might promote “wandering” on leaf surfaces, thereby increasing temporal and spatial exposure to insecticides. This study shows that the PE kairomone can improve insecticide efficacy and contribute to new control tactics for both CM and NOW, while reducing the incidence of Aspergillus and aflatoxin contamination of nuts. Technical Abstract: Aspergillus invasion of tree nuts is primarily through insect damage by moth larvae, such as the codling moth (CM) attacking walnuts. Our goal is to diminish insect-caused nut damage through the use of novel, species-specific host-plant kairomones. We have identified the pear ester (PE) (ethyl (2E, 4Z)-2,4-decadienoate), as a powerful kairomone, attracting neonate larvae. We investigated using PE as an adjuvant to improve the use of insecticides. Food Quality Protection Act 1996 will soon restrict/ban use of organophosphate (OP) insecticides. Alternative insecticides must be made more effective and affordable. Because we found that neonate CM larvae are highly attracted to PE, we hypothesized that bait-sprays of kairomone + insecticide might attract - kill larvae more effectively. Micro-encapsulated sprayable formulation of PE (PE-MEC) was tank-mixed as an adjuvant with reduced rates of insecticides and applied by handgun-sprayers. Eight single-tree replicates were used per treatment in a 20 acre walnut orchard. Treatments were the insecticides alone verses insecticide + PEK-MEC adjuvant. Four insecticides were tested, including two OPs, choropyrifos and phosmet, an insect growth regulator, methoxyfenozide, and a granulosis virus, Cyd-X. Results were significant, with PE-MEC adjuvant reducing CM harvest damage by 83%, 90%, 54% and 47% for the insecticides. Navel orangeworm damage was also significantly reduced. These studies show promise that the pear ester kairomone can improve insecticide efficacy and help reduce aflatoxin incidence. |
