Title: Mortality of insect life stages during simulated heat treatment Authors
Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 11, 2013
Publication Date: N/A
Technical Abstract: . Heat treatment for insect disinfestation uses elevated air temperatures that are lethal to stored-product insects. Heat treatment has been demonstrated in our research to offer a reduced-risk alternative to fumigation or residual pesticide use in empty bins. Heat is also compatible with organic grain production. However, little information is available on using heat as a means to disinfest empty grain drying bin plenum areas. Previous research has shown that larvae and pupae of internal insects can be harder to kill with heat than insects outside kernels. An additional issue is the layer of fines and dust that accumulates under false drying floors and insulates the surface of the concrete subfloor floor, providing a safe haven for insects to escape the lethal heat above. Tests were conducted in laboratory ovens to assess the different requirements for internal insects versus those outside the kernel and the effect of a cover layer of fines and dust on efficacy of the heat treatment. Results showed that the internal insects required significantly longer times of exposure to heat for 100% kill. A 1 to 2 cm deep cover layer of fines reduced the floor surface temperature by 10° to 20°C in typical treatment scenarios; the temperature reduction affect was nonlinear with cover layer depth. Results from laboratory ovens with simulated concrete floor surfaces will be presented showing the effect of air temperature, covering depth, time, and insect life stage on insect mortality during heat treatments.