Heat treatment for disinfestation of empty grain storage bins

Authors: Tilley, Dennis; Casada, Mark; Arthur, Franklin

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2006
Publication Date: 4/5/2007
Citation: Tilley, D.R., Casada, M., Arthur, F.H. 2007. Heat treatment for disinfestation of empty grain storage bins. Journal of Stored Products Research. 43:221-228.

Interpretive Summary: Experts generally recommend chemical methods to disinfest empty grain bins below the drying floor because disassembly and cleanout are too time consuming to be practical. However, heat treatment, with temperatures above 50°C has been effective as a non-chemical disinfestation method for similar situations in grain processing plants. In field tests with 5000 bu round metal bins we achieved 100% mortality for three common stored-product insects, red flour beetle, rice weevil, and lesser grain borer, after heat treatments with a simple system using a 29 kW propane heat source. Lower power systems required complex heat distribution or recirculation systems to be effective. These results indicate that heat treatment with properly designed systems provides an option, as part of an integrated pest management program, to greatly reduce or eliminate chemical use for pre-binning disinfestation of grain storage bins.

Technical Abstract: An alternative to fumigants and insecticides for controlling stored-product insects in empty grain storage bins prior to filling is heat treatment in which the temperature is quickly raised to a minimum of 50°C and held there for two to four hours. Effectiveness of heat treatments on empty grain storage bins was evaluated for five readily-available propane and electric heat treatment systems by measuring temperature and the mortality of Tribolium castaneum (Herbst), Sitophilus oryzae (L.), and Rhyzopertha dominica (F.) at three time intervals. Eleven locations, six above and five below the drying floor, were monitored for temperature and mortality of the three insect species using arenas initially stocked with live adult insects. Data were analyzed separately for each heating system with floor location and time interval as main effects for insect mortality. The high output propane heater (29 kW) produced 100% mortality in 2 h for the three insect species at all test area locations. The electric duct heater system (18 kW) also produced 100% mortality at all test area locations after 40 h when aided by a complicated interior heat distribution system. The other three systems produced less than 100% mortality.