Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 22, 2002
Publication Date: March 15, 2004
Citation: ARTHUR, F.H., HOERNEMANN, C.K. IMPACT OF PHYSICAL AND BIOLOGICAL FACTORS ON SUSCEPTIBILITY OF TRIBOLIUM CASTANEUM AND TRIBOLIUM CONFUSUM (COLEOPTERA: TENEBRIONIDAE) TO NEW FORMULATIONS OF HYDROPRENE. JOURNAL OF STORED PRODUCTS RESEARCH 40: 251-268. 2004. Interpretive Summary: New insecticides developed to control insect pests in stored products must be at least equivalent in efficacy to current products. In a series of tests, two experimental formulations of the insect growth regulator hydroprene were compared to an established commercial formulation of hydroprene (Gentrol). Both new formulations controlled the red flour beetle and the confused flour beetle, two common insect pests in food storage facilities. Residual control lasted about 6-12 weeks on clean concrete but less than 6 weeks on concrete contaminated with flour. Results show the effectiveness of the new formulations and also demonstrate the importance of sanitation in conjuction with insecticide applications.
Technical Abstract: Late instars of Tribolium castaneum (Herbst), the red flour beetle, and Tribolium confusum (DuVal), the confused flour beetle, were exposed on concrete treated with two experimental formulations of hydroprene and an established commercial formulation of hydroprene (Gentrol). When the experimental formulations and Gentrol were applied at comparable label rates, there were no differences regarding the percentage of individuals arrested in the larval stage (arrested larvae). Late instars of T. confusum were also exposed for 6 and 12 weeks on concrete treated with 1.9 x 10-3 mg [AI]/cm2 of hydroprene formulations 202-080 and 202-084, and stored at 22 or 32°C, 40 or 75% r.h. At 6 weeks, there were fewer arrested larvae, more live adults, and fewer dead adults with morphological deformities on treated concrete stored at 22°C - 75% r.h compared with the other 3 temperature-r.h. combinations. At 12 weeks there were fewer live adults and dead adults with gross morphological deformities on concrete treated with formulation 202-084 and stored at 32°C - 75% r.h. compared with the other temperature-r.h. combinations. In a final experiment, concrete was treated with 1.9 x 10-3 mg [AI]/cm2 of both formulations 202-080 and 202-084, approximately 500g of flour were added to the individual arenas, and bioassays were conducted with late-instar T. confusum. There were few live adults at the 0-week bioassays, and dead adults with gross morphological deformities ranged from 83.1 to 97.6%. However, at 6 weeks there were no dead adults with gross morphological deformities, except in bioassays conducted at 27°C- 57% r.h. on concrete treated with formulation 202-084. The presence of the flour apparently compromised residual control and the hydroprene was no longer effective.