Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2003
Publication Date: 1/15/2004
Citation: Epsky, N.D., Shuman, D. 2004. Arena Size and Capture of Oryzaephiles Surinamenus (Coleoptera: Silvanidae) in Grain Probe Traps. J. Econ. Entomol. 97:150-154 Interpretive Summary: Insect infestations in stored grain cost U.S. agriculture millions of dollars in damage due to contamination and loss of grain. Availability of automated monitoring systems will allow off-site monitoring of stored grain, which will give the grain storage operators an important tool to aid in making pest management decisions. Scientists at the Subtropical Horticulture Research Station and at the Center for Medical, Agricultural, and Veterinary Entomology are conducting research to optimize a prototype automated monitoring system, which uses an electronic grain probe trap. Research was conducted to determine the relationships among size of test arena, number of openings in the body of the grain probe trap and capture of pests of stored grain. A higher percentage of insects were captured in tests conducted in the smallest arenas due to both higher temperatures that occurred in these arenas and to increased contact between insects and the grain probe, but number of openings in the grain probe trap had no effect. This information will be useful in evaluation of systems developed for commercial application. Availability of commercially available, automated grain monitoring system will facilitate technology transfer of this novel detection system for stored product pest management.
Technical Abstract: The relationship of size of test arena, number of holes in a grain probe trap body and capture of the sawtoothed grain beetle, Oryzaephilus surinamensis (L.), was determined in simulated field tests conducted in a screen room exposed to natural temperature fluctuations. Polyvinylchloride (PVC) probe bodies were attached to electronic sensor heads, and insect captures were recorded electronically using an Electronic Grain Probe Insect Counter (EGPIC) system. In comparisons among PVC probe trap bodies with 60, 132, 252 and 492 holes, tested at 18 insects per kg in 4.5, 17 and 40 kg of soft wheat in cylindrical arenas (10.2, 20.3 and 30.5 cm diam, respectively), number of holes in the probe trap body had no effect on insect capture, but percentage of insects recovered was indirectly related to size of the test arena. Periodicity of insect capture was determined using the time-stamp data that were recorded by the EGPIC system. Circadian rhythm was observed in the periodicity of the capture which corresponded to foraging activity peaks documented for sawtoothed grain beetles, with activity peaks occurring earlier in the scotophase. There were shifts in times of peak activity among the different test arena sizes that corresponded to differences in temperature in the grain mass. Arenas with the two larger diameters took longer to heat up and to cool down, and range of temperatures from maximum to minimum was smaller than ambient temperatures and temperatures in the 10.2 cm diam arena. Thus, increases in both temperature and contact between insects and grain probe in the smallest arenas resulted in higher recapture of sawtoothed grain beetles and are important factors to consider in tests of grain probe trap efficacy.