Aeration Management for Stored Hard Red Winter Wheat: Simulated Impact on Rusty Grain Beetle (Coleoptera: Cucujidae) Populations

Abstract

Simulation studies were conducted to determine temperature accumulations below defined thresholds and to show the impact of controlled aeration on populations of the rusty grain beetle, Cryptolestes ferrigineus (Stephens), a major secondary pest of stored wheat, Triticum aestivum (L.). Recorded data from weather stations in Texas, Oklahoma, Kansas, eastern New Mexico, and eastern Colorado (356 total) were used to determine hours of temperature accumulation below 23.9 degrees C in June and July, 15.6 degrees C in September and October, and 7.2 degrees C in December. At an airflow rate of 0.0013 m3/s/m3 (0.1 cubic ft3/min/bu), which requires 120 h of temperatures below the specified threshold to complete an aeration cycle, summer cooling at 23.9 degrees C in bulk-stored wheat could be completed throughout the hard red winter wheat zone except for extreme southern Texas. An early-autumn cooling cycle at 15.6 degrees C could not be completed throughout most of Texas and Oklahoma before the end of September. The late-autumn cooling cycle could be completed in all states except Texas by the end of November. Five geographic regions were delineated and the times required for completion of the summer, early-autumn, and late-autumn cooling cycles within each region were estimated. Population growth of the rusty grain beetle was modeled for San Antonio, TX; Abilene, TX; Tulsa, OK; Topeka KS; and Goodland, KS, by predicting the numbers of adults in the top, outer middle, outer periphery, and the center of the bin during a 1-yr storage season. Populations of C. ferrugineus in San Antonio and Austin were predicted to exceed the Federal Grain Inspection Service (FGIS) threshold of two beetles per kilogram of wheat in all four levels of the bin during late autumn, decline during the winter, and increase the following spring. In Midland, TX, and Oklahoma City, OK, populations were predicted to exceed the threshold only in the top and outer middle of the bin, whereas populations in the Kansas locations were not predicted to exceed the threshold at any time.

Comparison of Aeration and Spinosad for Suppressing Insects in Stored Wheat

“…If the product becomes available for stored wheat, it would be invaluable especially in situations where a high degree of insect control is needed, and/or in climates where aeration is not as effective in suppressing insects, such as in the more southern states (Arthur and Flinn 2000). The advantage of aeration is that it provides good insect suppression, with no insecticidal residues, at a relatively low cost (electrical costs are Ϸ1 cent/27 kg of wheat).…”

“…In most of the United States, controlled aeration is effective in suppressing insect population growth in bins of stored wheat (Flinn et al 1997, Reed and Harner 1998, Arthur and Flinn 2000. This method uses a simple thermostat controller that turns on an electrical fan.…”

“…Therefore, spinosad or aeration should be effective in controlling insects during this period. Insect populations in unaerated bins generally reach high levels under Kansas weather conditions (Flinn et al 1997, Arthur andFlinn 2000). Our objectives were to determine whether spinosad was a viable product for use on wheat stored in unaerated bins and to compare spinosad with controlled aeration.…”

Temperature-dependent population growth of three species of stored product mites (Acari: Acaridida)

“…Physical control of mites and insects in stored grain, including management of grain moisture and temperature, is the only major viable option remaining (Arthur and Flinn 2000). Moisture and temperatures are known to affect population growth of stored product mites (Solomon 1962;Baker 1967;Cunnington 1976;Sanchez-Ramos et al 2007).…”

Use of a Web-Based Model for Aeration Management in Stored Rough Rice

“…Simple controllers activate the aeration fan(s) when outside temperatures drop below set levels, whereas more complex controllers measure internal temperature at speciÞed locations in the grain mass and ambient temperature outside the bins and are activated by comparing ambient and internal grain mass temperature. There are several modeling simulation studies that predict the impact of aeration on insect populations in corn, Zea mays L., stored in the United States (Maier et al 1996;Arthur et al 1998Arthur et al , 2001Throne and Arbogast 2010) and in wheat stored in the United States (Flinn et al 1997, Arthur andFlinn 2000). Field studies also have been conducted with aeration on corn (Arthur and Throne 1994) and wheat (Reed and Harner 1998a,b;Casada et al 2002;Flinn et al 2004;Arthur andCasada 2005, 2010).…”