Skip to main content
ARS Home » Research » Publications at this Location » Publication #162869
Title: ESTIMATING POPULATIONS OF GRAIN BEETLES USING PROBE TRAPS IN WHEAT-FILLED CONCRETE SILOS

Author
item Toews, Michael
item PHILLIPS, THOMAS - OKLAHOMA STATE UNIV
item PAYTON, MARK - OKLAHOMA STATE UNIV

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/2005
Publication Date: 8/1/2005
Citation: Toews, M.D., Phillips, T.W., Payton, M. 2005. Estimating populations of grain beetles using probe traps in wheat-filled concrete silos. Environmental Entomology 98(4):1391-1398.

Interpretive Summary: Traps are used to estimate insect populations in grain stored in steel bins, but the utility of traps for estimating insect populations in concrete silos has not been established. Estimating insect population density in silos containing stored wheat is difficult because obtaining and processing large grain samples is labor intensive and requires specialized equipment. Furthermore, silo entry requires a confined space entry permit in the United States. This study demonstrated how inexpensive probe traps could be used to estimate insect density in commercial silos. We were able to predict insect population in the grain based on number of insects captured in the probe traps, grain temperature, and depth of the trap in the grain. This information will be useful for methodical use of grain probe traps in the pest management decision-making process.

Technical Abstract: Probe traps are sensitive tools for detecting populations of beetles in stored grain, but their utility for estimating insect density in concrete silos has not been established. Populations of grain beetles infesting wheat in concrete silos at two commercial storage facilities in north central Oklahoma were sampled using probe traps and grain probe samples over a 17-wk period. Grain temperature and quality parameters were collected during the study. Thirteen insect species were detected using probe traps while 8 species were detected with the grain samples; Cryptolestes ferrugineus and Rhyzopertha dominica were the most common insects collected in the grain samples. Across dates, there were no differences in mean number of principal species recovered near the grain surface and 1 m below in either probe traps or grain samples. Comparison of slopes (probe trap capture vs. insects recovered in grain samples) showed that there were significant differences by trap position for C. ferrugineus but not R. dominica. Multiple regression models, developed to predict insect population estimates using number of insects captured in probe traps and a temperature component, indicated that more variability in the data was explained using traps positioned 1 m below the grain surface (r2=0.70) than near the surface (r2=0.22) for C. ferrugineus. About half (r2=0.56) of the variability in insect density was described for R. dominica. These models demonstrate the potential for methodical use of grain probe traps in pest management decision-making.