The Influence of Elevated Temperatures on a Residual Insecticide and Inert Dust to Disinfest Empty Bins Prior to On-farm Grain Storage

View the project final report

• 2015 annual report

Commodities

• Agronomic: corn, wheat

Practices

• Education and Training: extension, technical assistance
• Pest Management: chemical control, integrated pest management, physical control, prevention
• Sustainable Communities: sustainability measures

It is good practice for farmers to clean their grain bins before storing newly harvested grain. Unsanitary bins can harbor unwanted insects that infest grains, including the red flour beetle (Tribolium castaneum (Herbst)), the saw tooth grain beetle (Oryzaephilus surinamensis (Linnaeus)), and the lesser grain borer (Rhyzopertha dominica (Fabricius)). Due to the fact that it is difficult and labor intensive for farmers to clean under the perforated floor of steel grain bins, where many insects thrive due to the presence of grain dust and broken kernels, it is necessary to employ other methods to control stored-product insects prior to refilling the bin. The use of elevated temperatures has been previously documented as an effective method to kill stored-product insects within 2-4 hours when temperatures of 50-60°C are reached and maintained in empty bins. Previous research has shown that the efficacy of residual insecticides or inert dusts against stored-product pests can be increased after application followed by heat treating the bin with temperatures below 50°C. Laboratory trials will be conducted to determine the efficacy of a low toxicity insecticide (Diacon) and the inert dust, diatomaceous earth (DE), on concrete dishes to simulate the floor of a grain bin against 20 adults of T. castaneum, and then held at 28, 32, 36, 42, 44 and 46°C for 4-24 h. Based on the results, Diacon or DE will be chosen for further validation in field trials using empty 3000 bu bins, with and without heat treatments. Bioassays containing adult insects will be placed inside the bins to determine the efficacy of treatment. The end result of this research will be to provide guidelines to farmers about the optimal time to apply residual insecticides or inert dusts to bins prior to storage based on temperatures inside the bins. In addition, the relationship of Diacon or DE in combination with heat treatments on the mortality of stored-product insects will be determined.

The aim of this study is to determine the interaction between temperature and either a  low toxicity residual insecticide or an inert dust to control populations of three species of stored-product insects commonly found in grain bins. Laboratory trials will be conducted to determine the most effective treatment and temperature combination for the highest mortality of each species, followed by field trials conducted in empty farm bins for field validation.

The research being proposed will determine the optimal temperature at which to apply Diacon or DE, which are sustainable methods, to disinfest empty grain bins prior to storage of newly harvested grain. Based on the results, the short-term outcome of this project is to increase the awareness of farmers to more sustainable methods of disinfesting empty storage bins. In addition, farmers will have an increased knowledge about time and labor reducing methods to be used in conjunction with their integrated pest management (IPM) program. Intermediate outcomes include better timing of residual insecticide or inert dust application to bins based on temperature conditions inside storage bins to maximize their efficacy.  This can be accomplished by hosting short-courses or extension programs specifically for farmer education on new methodologies.  The long-term outcome of this project will be to increase grain quality and profitability for farmers in the North Central region and changed attitudes towards preventive actions to be taken by farmers to ensure increased grain quality.