Author
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Johnson, Judy |
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Valero, Karen |
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Submitted to: Proceedings of International Research Conference on Methyl Bromide Alternatives
Publication Type: Abstract Only Publication Acceptance Date: 8/20/2003 Publication Date: 11/20/2003 Citation: Johnson, J.A., Valero, K.A. 2003. Survival of Indianmeal moth and navel orangeworm at low temperatures. Proceedings of International Research Conference on Methyl Bromide Alternatives. November 3-6, 2003, San Diego, California. Paper No. 70. Interpretive Summary: The navel orangeworm, Amyelois transitella, and Indianmeal moth, Plodia interpunctella, are important postharvest insect pests of California dried fruits and nuts. These insects are unable to feed, develop or reproduce below developmental thresholds of about 14C. Extended exposure to temperatures below developmental thresholds eventually causes death. Dried fruit and nut processors often store their product at temperatures of 5C or below to maintain quality and lengthen self-life. Cold storage may also be used to protect product from insect infestation, and as a possible disinfestation treatment. We have determined the life stages that are most tolerant to 0, 5, and 10C and have estimated the exposures necessary for disinfestation at 0 and 5C. Larvae of both species were very tolerant of exposure to 10C, less than 50% mortalty occurring after 40 days. Indianmeal moth larvae were more cold tolerant than navel orangeworm at all temperatures. At 0C, pupae were more tolerant than larvae. Eggs were the most susceptible stage to low temeratures. Our results indicate that long exposures would be necessary to disinfest product of either Indianmeal moth or navel orangeworm larvae at 10C. Shorter exposures were obtained at lower temperatures, with near complete mortality reached after 25 days at 5C and after 12 days at 0C. Because these temperatures are more likely to be used under commercial conditions, disinfestation of stored product may be possible with little change to normal storage practices. However, the method will not be applicable to product that requires rapid treatment. Technical Abstract: The navel orangeworm, Amyelois transitella, and Indianmeal moth, Plodia interpunctella, are important postharvest insect pests of California dried fruits and nuts. These insects are unable to feed, develop or reproduce below developmental thresholds of about 14C. Extended exposure to temperatures below developmental thresholds eventually causes death. Dried fruit and nut processors often store their product at temperatures of 5C or below to maintain quality and lengthen self-life. Cold storage may also be used to protect product from insect infestation, and as a possible disinfestation treatment. We have determined the life stages that are most tolerant to 0, 5, and 10C and have estimated the exposures necessary for disinfestation at 0 and 5C. Larvae of both species were very tolerant of exposure to 10C, less than 50% mortalty occurring after 40 days. Indianmeal moth larvae were more cold tolerant than navel orangeworm at all temperatures. At 0C, pupae were more tolerant than larvae. Eggs were the most susceptible stage to low temeratures. Our results indicate that long exposures would be necessary to disinfest product of either Indianmeal moth or navel orangeworm larvae at 10C. Shorter exposures were obtained at lower temperatures, with near complete mortality reached after 25 days at 5C and after 12 days at 0C. Because these temperatures are more likely to be used under commercial conditions, disinfestation of stored product may be possible with little change to normal storage practices. However, the method will not be applicable to product that requires rapid treatment. |
