Submitted to: Entomology Society of America Pacific Branch Meeting
Publication Type: Abstract only
Publication Acceptance Date: 1/25/2011
Publication Date: 3/27/2013
Citation: Johnson, J.A., Wang, S., Jiao, S., Tang, J. 2013. Effect of radio frequency treatments on cowpea weevil adults. Entomology Society of America Pacific Branch Meeting, March 27-30, 2011, Waikoloa, Hawaii. p. 61-62. Interpretive Summary:
Technical Abstract: Dried pulses (chickpeas, lentils and dried peas) are valuable export commodities in the US Pacific Northwest. Postharvest infestation by stored product insect pests such as the cowpea weevil may cause importing countries to require phytosanitary treatments before shipment. Typically, chemical fumigants are used to disinfest dried pulses, but the industry is exploring non-chemical alternatives. One possible alternative is the use of radio frequency (RF) energy to rapidly heat product to insecticidal levels. Preliminary studies have showed that although cowpea weevils are more heat tolerant than other tested postharvest insects, RF treatments coupled with 60°C hot forced air should provide adequate control. However, one issue that must be addressed is the possible escape of active cowpea weevil adults as product heats during RF treatments. This paper examines the behavioral and mortality response of adult cowpea weevil to sudden high temperatures. Adults were observed to attempt to escape temperatures of 40-45°C, and reached heat stupor at temperatures of 56-60°C. Complete mortality of adults was obtained after exposure to 60°C for 25 seconds. Combinations of RF and 60°C hot forced air did not allow adults to escape the treated product. Adults present on the surface of the treated product moved into the product, apparently to avoid the hot air, and were eventually killed as RF energy heated the product to lethal levels. Thus, RF treatments in combination with forced hot air should effectively control cowpea weevil in dried pulses.