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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Crop and Commodity Protection Research » Research » Publications at this Location » Publication #432508
Research Project: Innovative Crop Protection and Postharvest Systems to Improve Market Access and Product Quality

Location: Tropical Crop and Commodity Protection Research

Title: Efficacy of the proposed generic irradiation dose for Coleoptera confirmed for two grain pests

Author
item Follett, Peter
item Liang, Peishih

Submitted to: Journal of Asia-Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2026
Publication Date: 5/1/2026
Citation: Follett, P.A., Liang, P. 2026. X-ray irradiation to control the stored product pests Cathartus quadricollis and Oryzaephilus surinamensis (Coleoptera: Silvanidae). Journal of Asia-Pacific Entomology. 29(2). https://doi.org/10.1016/j.aspen.2026.102568.
DOI: https://doi.org/10.1016/j.aspen.2026.102568

Interpretive Summary: Irradiation dose response tests were conducted with the stored products pests saw-toothed grain beetle, Oryzaephilus surinamensis, and square-necked grain beetle, Cathartus quadricollis. These beetles are minor pests of stored grains, oilseeds and nuts. Both beetle species were sterilized with a radiation doe of 100 Gy. The radiosensitivity of C. quadricollis and O. surinamensis falls within the 150 Gy generic dose that has been proposed for all beetles (Coleoptera). Irradiation is a viable disinfestation treatment option for stored products pests.

Technical Abstract: Irradiation is a disinfestation treatment option for stored products pests. Dose response tests were conducted to identify a postharvest irradiation treatment that would control the square-necked grain beetle, Cathartus quadricollis (Coleoptera: Silvanidae) and the saw-toothed grain beetle, Oryzaephilus surinamensis (Coleoptera: Silvanidae). Cracked corn infested with adult C. quadricollis was treated with x-ray radiation at 0 (control), 60, 90, 120 or 150 Gy, and cracked corn infested with adult O. surinamensis was treated at 0 (control), 50, 75, 100, 125, and 150 Gy. Live and dead beetles were counted weekly for 8 to 12 weeks. For both species, the rate of mortality generally increased with increasing dose. For C. quadricollis adults, reproduction was observed only in untreated controls and at 60 Gy; no reproduction was observed at 90, 120, or 150 Gy. For O. surinamensis adults, significant reproduction was observed only in untreated controls and in the 50 Gy treatment but a few F1 generation adults were found in the 75 Gy treatment; no reproduction was observed at 100, 125, or 150 Gy. For both species, all the adults irradiated at 150 Gy were dead after three weeks. A minimum radiation dose of 100 Gy would be an effective treatment providing quarantine security for both species. The radiosensitivity of C. quadricollis and O. surinamensis falls within the 150 Gy generic dose that has been proposed for all Coleoptera.