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Title: Thermal treatments to increase acoustic detectability of Sitophilus oryzae (Coleoptera: Curculionidae) in stored grain

item Mankin, Richard
item Shuman, Dennis

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/1998
Publication Date: N/A
Citation: Mankin, R.W., Shuman, D., Weaver, D.K. 1999. Thermal treatments to increase acoustic detectability of Sitophilus oryzae (Coleoptera: Curculionidae) in stored grain. Journal of Economic Entomology. 92:453-462.

Interpretive Summary: Scientists at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL have developed acoustic technology to automate the inspection of grain for insect infestation and to enable detection of immature insects that feed inside grain kernels. These techniques have the potential to reduce the costs of inspection by the USDA Federal Grain Inspection Service and to reduce the use of insecticides. The principle of operation is that insect activity can be detected by sensitive microphones. However, excessive handling of samples or cool temperatures can reduce insect activity levels, making infestations harder to detect. This report describes grain sample pretreatments that can restore insect activity to optimal levels.

Technical Abstract: Acoustic detection of hidden larval infestations in stored grain is enhanced during periods of high insect activity. In this report, several different radiant and convective heat pretreatments of grain samples were tested for their potential to increase insect activity and improve the reliability of acoustic inspection techniques. During the first 20 min after a brief exposure to heat, activity rates of Sitophilus oryzae (L.) Larvae taken from a 10 or 16 C environment increased by a factor of 2-5 compared with untreated controls. However, heat exposure did not affect larvae held initially at room temperature (26 C). Brief mechanical disturbances inhibited larval activity for about 20 min. These results suggest that, in general, sound production of larvae is enhanced if cold grain samples are warmed and all samples are left undisturbed for 15- 20 min before inspection.