Submitted to: International Congress of Entomology
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2012
Publication Date: 8/21/2012
Citation: Johnson, J.A. 2012. Current status of non-chemical methods for control of insect pests in dried fruits and nuts. International Congress of Entomology. Paper No. S1202TU18.
Technical Abstract: Regulatory agencies and consumers have no tolerance for live insects in dried fruit and tree nut commodities; consequently, successful marketing of these products requires postharvest treatments designed to kill any pest insects. Recent regulatory actions have severely limited the use of chemical fumigants by US dried fruit and nut processors to control postharvest insect populations. Non-chemical treatments would provide an alternative to fumigation, and would also be useful to organic processors. One proposed treatment uses radio frequency energy to rapidly heat walnuts to an average temperature of 60°C for 5 minutes. Large-scale tests using an industrial radio frequency heater successfully disinfested walnuts of navel orangeworm while maintaining good product quality. A second alternative exposes product to a low pressure environment of 50 mm Hg in flexible polyvinyl chloride containers. Temperature and moisture content of the product strongly affects treatment efficacy, with complete mortality of test insects achieved at treatment exposures of 48-72 hours under optimal conditions. Another alternative is the use of cold storage (0-5°C) to either disinfest product or prevent reinfestation of clean product, and may be effectively combined with other non-chemical treatments. At temperatures of 0 and 5°C, 95% mortality of test insects was achieved at 10 and 18 days, respectively. Storage at 10°C prevented reproduction, product damage and reinfestation, but 127 day exposures were required to kill 95% of Indianmeal moth larvae. While these non-chemical treatments are effective, they usually require considerable capital investment and modification of existing processing plants, slowing their adoption by the industry.