Submitted to: Applied Engineering in Agriculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/22/2005
Publication Date: 12/1/2005
Citation: Arthur, F.H., Casada, M. 2005. Feasibility of summer aeration to control insects in stored wheat. Applied Engineering in Agriculture 21: 1027-1038. Interpretive Summary: Insect pests often cause economic damage in stored grain, and cooling storage bins in autumn through aeration (using low-volume airflow rates of ambient air) can be an important component of integrated management plans for stored wheat. Model simulation studies show that a summer aeration cycle would cool stored wheat in Kansas and also reduce insect populations, but field studies have not been done to verify model predictions. We conducted a 3-year study in which summer aeration was included along with aeration in early and late autumn. Summer aeration reduced temperatures in stored wheat and generally reduced insect populations, but year-to-year variations in temperatures affected the level of control. Results warrant further research into the timing and optimization of summer aeration.
Technical Abstract: Temperature profiles and insect populations were compared in wheat that had been aerated with low airflow rates during the summer in addition to two autumn aeration cycles, versus wheat aerated in autumn only or unaerated. Tests were in 2000-2001, 2001-2002, and 2002-2003, and data were analyzed separately for each year. Temperature profiles at depths of 0.9 and 1.8 m in the grain mass showed distinct declines in temperature for each aeration cycle during the first two years of the study, however, summer aeration did not result in as large of temperature declines in 2002-2003, partly because the summer aerated bin was loaded with warmer grain. The effectiveness of summer aeration was estimated using confined insect populations in tube cages placed on the surface of the grain and by sampling 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 rice weevil, Sitophilus oryzae (L.) in the tube cages were consistently lower in bins that had not been aerated during the summer, possibly because without aeration temperatures in the top surface of the grain mass were high enough to limit insect populations. 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 seem to support modeling simulation studies that predict lower insect populations when a summer aeration cycle is included, however, the timing and the effectiveness of this extra aeration may vary depending on when the bins are loaded, the weather patterns for a particular year, and the presence and severity of natural infestations of insects.