Susceptibility of Tribolium castaneum and Trogoderma variabile larvae and adults exposed to methoprene-treated woven packaing material

Authors: Scheff, Deanna; SUBRAMANYAM, BHADRIRAJU - Kansas State University; Arthur, Franklin

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2017
Publication Date: 9/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5814440
Citation: Scheff, D.S., Subramanyam, B., Arthur, F.H. 2017. Susceptibility of Tribolium castaneum and Trogoderma variabile larvae and adults exposed to methoprene-treated woven packaing material. Journal of Stored Products Research. 73:142-150. https://doi.org/10.1016/j.jspr.2017.08.002.
DOI: https://doi.org/10.1016/j.jspr.2017.08.002

Interpretive Summary: Stored-product insects, such as the red flour beetle and warehouse beetle, are serious pests in processed grains, pet foods, and packaged food products, and fumigation treatments are often necessary to eliminate insect infestations. Impregnating the insect growth regulator methoprene into packaging materials is a new technology and can be used to prevent infestation of packaged foods in warehouses, transportation vessels, and retail marketplaces. The packaging material consists of three layers, with the methoprene impregnated in the middle layer. After larvae of either red flour beetle and warehouse beetle were added to either the inner or outer surfaces of methoprene impregnated material, normal adult emergence decreased with increasing exposure time and temperature. Exposure on methoprene-treated packaging as an adult did not adversely affect number of offspring of warehouse beetle, but did affect fecundity of red flour beetle. Continual exposure gave 100% suppression of red flour beetle adult emergence and a reduction of warehouse beetle emergence, indicating red flour beetles are more susceptible to methoprene-treated woven packaging. Additionally, we determined that the outside surface of the packaging was more effective at inhibiting larval development compared to the inside surface. The methoprene-treated packaging had little effect on the number of eggs laid or egg hatch of either species. Our results demonstrate that methoprene impregnated packaging materials can be incorporated into an existing insect management program to prevent stored-product insect infestations.

Technical Abstract: Methoprene is an insect growth regulator (IGR) registered in the United States for direct application to stored raw grains, as an aerosol or residual contact insecticide, or for use as a packaging treatment for protection of bagged processed food products. A series of tests were conducted to determine the effect of short term exposure, continual exposure, and sub-lethal effects on the red flour beetle, Tribolium castaneum (Herbst) and warehouse beetle, Trogoderma variabile Ballion, on the inside and outside surfaces of methoprene treated woven packaging material at 27 and 32'C and 60% r.h. In the first test, larvae of either T. castaneum or T. variabile were added to individual arenas and exposed for different time intervals, then removed from arenas, and resulting adult emergence was assessed. In the second test, eggs of both species were exposed on the packaging surfaces to determine percent egg hatch. In the third test, adults of T. castaneum and T. variabile were added to arenas and held for 7 d and 3 d, respectively, to determine number of eggs laid per female and egg hatchability. In the fourth test, eggs were held on arenas to determine the effect of continual exposure. Results showed normal adult emergence decreased with increasing exposure time and temperature. Methoprene-treated packaging did not adversely affect adult fecundity of T. variabile, but showed an effect on T. castaneum. Continual exposure demonstrated 100% suppression of T. castaneum adult emergence and a reduction of T. variabile emergence, indicating T. castaneum is more susceptible to methoprene treated woven packaging.