Why is suction (down-flow) aeration considered a primary IPM tool?
Suction aeration allows rapid cooling of surface and top 1-2 meters (3.3-6.6 ft) of grain for fast, non-chemical suppression of all stored grain insect populations. Insect populations begin to develop in summer harvested stored grains within 2-3 weeks of storage. Entomologists have found that each 10oF reduction in grain temperature (95 to 85oF, and 85 to 75oF) reduces most types of insect feeding and breeding activity by about 50% (depending on insect species). Cooling insects below 60oF causes most stored grain insect breeding activity to stop. Thus, cooling wheat from an optimum insect temperature of 85-95oF to 70-75oF during July and August can greatly reduce population buildup. Suction aeration is especially important for control of Indian meal moth (IMM), as well as lesser grain borer (LGB), and rice weevil (RW), the most damaging stored grain insects. IMM live near the grain surface and LGB move very slowly. At the standard commercial aeration airflow rate of 0.1 (1/10) cfm/bu,
