FEASIBILITY OF SUMMER AERATION TO CONTROL INSECTS IN STORED WHEAT

Abstract

Temperature profiles and insect populations were compared in wheat that had been aerated with low airflow ratesduring the summer in addition to two autumn aeration cycles, versus wheat aerated in autumn only or unaerated wheat. Testswere conducted in 2000-2001, 2001-2002, and 2002-2003, and data were analyzed separately for each year. Grain masstemperature profiles at depths of 0.9 and 1.8 m from the surface in the grain mass showed distinct declines in temperaturefor each aeration cycle during the first two years of the study, however, summer aeration did not result in as large oftemperature declines in 2002-2003, partly because the summer aerated bin was loaded with warmer grain. The effectivenessof summer aeration was estimated using confined insect populations in tube cages placed on the surface of the grain and bysampling the grain for natural insect populations using pitfall probe traps. At the conclusion of the summer aeration cycle,the number of lesser grain borer, Rhyzopertha dominica (Fabricius), red flour beetle, Tribolium castaneum (Herbst), and riceweevil, Sitophilus oryzae (L.) in the tube cages were consistently lower in bins that had not been aerated during the summer.Pitfall trap catch of rusty grain beetles, Cryptolestes ferrugineus (Stephens), hairy fungus beetle, Typhaea stercorea (L.),foreign grain beetle, Ahasverus advena (Walt), and lesser grain borer was consistently lower in bins with summer aeration,indicating a reduction in natural insect populations. Field data support modeling simulation studies that predict lower insectpopulations when a summer aeration cycle is included.