Aeration management for stored hard red winter wheat: Simulated impact on rusty grain beetle (Coleoptera : Cucujidae) populations

Simulation studies were conducted to determine temperature accumulations be low defined thresholds and to show the impact of controlled aeration on pop ulations 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 ac cumulation below 23.9 degrees C in June and July, 15.6 degrees C in Septemb er and October, and 7.2 degrees C in December. At an airflow rate of 0.0013 m(3)/s/m(3) (0.1cubic ft(3)/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 h ard red winter wheat zone except for extreme southern Texas. An early-autum n 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 cy cle could be completed in all states except Texas by the end of November. F ive geographic regions were delineated and the times required for completio n of the summer, early-autumn, and late-autumn cooling cycles within each r egion were estimated. Population growth of the rusty grain beetle was model ed 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 perip hery, and the center of the bin during a 1-yr storage season. Populations o f C. ferrigineus in San Antonio and Austin were predicted to exceed the Fed eral Grain Inspection Service (FGIS) threshold of two beetles per kilogram of wheat in all four levels of the bin during late autumn, decline during t he Minter, and increase the following spring. in Midland, TX, and Oklahoma City, OK, populations were predicted to exceed the threshold only in the to p and outer middle of the bin, whereas populations in the Kansas locations were not predicted to exceed the threshold at any time.