Developing Sustainable Stored Grain IPM Systems in Oklahoma and Texas
Work on this project over 2005 included the investigation of controlled summer aeration of bins of wheat to determine the difference in fan usage n accost in aerating manually vs using temperature-dependent fan controls. A cost-benefit analyses of fumigations vs several other IPM practices for stored grain was conducted using available cost data for typical grain elevators, and a decision-support system for IPM in grain elevators was evaluated that used regular systematic sampling of grain for insect pests. Several workshops were delivered in both fall and spring to elevator managers throughout Oklahoma in which results from this project were reported.
- Below are listed the revised original objectives that were proposed by the initial PI, Dr. Noyes. Dr. Phillips assumed the role of lead PI in 2005 after Dr. Noyes retired. Focused attenion was given to objectives 2, 3, 4 and 7 during 2005.
1. Demonstrate and compare closed loop fumigation (CLF) technology in well sealed storages with conventional fumigation as a cost effective, sustainable IPM component of Oklahoma and Texas farm and elevator grain storage systems to improve efficacy, safety, and profit.
2. Conduct physical and economic benefit analysis of suction vs pressure aeration systems operated by electro-mechanical automatic aeration controllers compared with manual control in steel bins and concrete silos at farms and elevators.
3. Document the practicality, including cost/benefits, of increasing aeration airflow rates from the standard 0.1 cfm/bu to 0.2-0.3 cfm/bu in bolted steel farm and elevator storage systems.
4. Evaluate physical and economic practicality of installing low airflow suction aeration plus CLF in existing concrete silos to minimize "grain turning" while improving sanitation and safety.
5. Document worker exposure to phosphine fumigant health hazards and safety using CLF vs conventional fumigation.
6. Establish a quarterly newsletter focused on grain storage IPM for farmers and elevator operators in OK, TX and other states available via OSU's Stored Product Internet web-site.
7. Develop a computer or website-based software model that will serve as an electronic bin board (current operating storage record of all grain in identified silos) and electronic grain blending model to provide repeatable, global optimum grain blending to meet contract or market specifications while maintaining the maximum amount of premium grain.
A computer-controlled automatic aeration and grain temperature management system was installed on experimental bins and evaluated throughout the storage season. Twelve of the bins were filled with wheat in 2005 and equipped with the fan control system. Half of theses bins were designated non-aerated and received no controlled aeration, while the other half were set to have the aeration fans turn on when the outside temperature dropped below the grain temperature. Bins with automatic aeration achieved grain temperatures about 10oC cooler than untreated bins by September 2005 and maintained this level of cooling throughout the storage season. This level of cooling can have a substantial impact on insect development and hence on level of infestation in aerated bins. Calculations based on fan running times, kW-hrs used by the fans and cost per kW-hr estimated that fan use for the 10-month storage period with the controlled aeration system cost about $0.0026 per kg, or about $0.07 per bu. This work demonstrates the potential for summer aeration to cool grain and reduce insect infestation early in the storage season.
The costs of alternative strategies for control of insects in the grain storage section of food processing facilities. In particular, costs of IPM strategies were compared with those of conventional pest control strategies, including routine fumigation. Components of the strategies considered include sampling, monitoring, aeration, fumigation, sanitation, and use of protectants (e.g., Malathion, Reldan). Specific costs considered include electricity (for aeration and turning), labor (for sampling, monitoring, fumigation, and sanitation), material costs for fumigant and/or protectant, equipment (for sampling, fumigation monitoring, and fumigation), and management costs. Data used are those assumed to represent conditions applicable to a typical grain company.
A computer-based decision support system was developed to conduct risk analysis of large commercial elevator facilities. A vacuum-probe sampler was used to take 10, 3-kg grain samples in the top 12 meters of each bin at grain elevators. After the insect species and numbers are determined for each sample, the data is entered into the risk analysis software. The program uses a model to predict future risk based on current density, grain temperature and moisture. The information is presented as a bin board layout to the manager. Recommended treatment strategies and economic analysis are presented to the manager. The system correctly predicted bins that were either safe or at high risk 72-78% of the time.
Impacts and Contributions/Outcomes
Eight separate grain elevator IPM workshops were held throughout Oklahoma in year 2005, and the results from this SARE project were presented and discussed with the participants. Additionally, relevant publications and conference presentations completed this year include the following.
Bonjour, E., T. W. Phillips and T .Pitts. 2005. Field evaluation of Spinosad and chlorpyrifos-mehtyl against stored wheat insect pests. Submitted paper at the Southwestern Branch Entomological Society of America meeting, 28 February-3 March, Albuquerque, NM.
Bonjour, E., T. W. Phillips and T .Pitts. 2005. Fiedl evaluation of Spinosad and chlorpyrifos-mehtyl against stored wheat insect pests. Submitted paper at the Southwestern Branch Entomological Society of America meeting, 28 February-3 March, Albuquerque, NM.
Bonjour, E. L., S. Lieu and T. W. Phillips. 2005. Field evaluation of three diatomaceous earth application treatments for controlling stored wheat insects. Display presentation, National Meeting of the Entomological Society of America, Dec. 16-18, Ft. Lauderdale, FL.
Liu, S., T. W. Phillips, F. Arthur, and D. VanGundy. 2005. Effects of combining aeration and methoprene against stored grain Insects. Display presentation, National Meeting of the Entomological Society of America, Dec. 16-18, Ft. Lauderdale, FL.
Liu, S., T. W. Phillips and F. H. Arthur. 2005. Potential of using insect growth regulators to control stored product pests. Submitted paper at the Southwestern Branch Entomological Society of America meeting, 28 February-3 March, Albuquerque, NM.
Phillips, T. W. 2006. The Science and Technology of Postharvest Insect Control: Challenges, Accomplishments and Future Directions. Chapter 19, pp. 211-222, In: J. Heaps, ed., Insect Management for Food Storage and Processing, 2nd Ed. Am. Assoc. Cereal Chem.
Puckette, J. A., T. W. Phillips, E.L. Bonjour and R. Beeby. 2005. Physical exclusion of insects from stored grain: laboratory and field studies. Submitted paper at the Southwestern Branch Entomological Society of America meeting, 28 February-3 March, Albuquerque, NM.