|SCHEFF, DEANNA - Kansas State University|
|SUBRAMANYAM, BHADRIRAJU - Kansas State University|
Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2016
Publication Date: 11/15/2016
Citation: Scheff, D., Subramanyam, B., Arthur, F.H. 2016. Effect of methoprene treated polymer packaging on fecundity, egg hatchability, and egg-to-adult development of Tribolium castaneum and Trogoderma variabile. Journal of Stored Products Research. 69:227-234. doi:10.1016/j.jspr.2016.07.003.
Interpretive Summary: Infestations of stored-product insects, including the red flour beetle and the warehouse beetle, can cause economic losses of packaged foods and food products by penetrating the bag and infesting the finished product. Insect-resistant packaging impregnated with the insect growth regulator methoprene is one option for protecting bagged and processed foods, but there is little data on the effectiveness of methoprene as a packaging treatment. We conducted tests by evaluating the outside and inside surfaces of different types of packaging impregnated with methoprene for control of red flour beetle and warehouse beetle. The outside surface of the treated bags effectively prevented any immature of either species from reaching the adult stage. Some warehouse beetle immatures were able to reach the adult stage on the inside surface of the packaging. Also, the packaging treatments reduced the number of eggs laid by female red flour beetles and hatching of those eggs, but not the warehouse beetle. Temperature did not affect the effectiveness of methoprene. Our results show that methoprene-based packaging can be used in management programs to help prevent stored product insects from penetrating and entering bagged products. However, there may be some differences in the susceptibility of different insect species to the packaging treatments.
Technical Abstract: Methoprene is a commonly used insect growth regulator for aerosol sprays, residual surface treatments, and as a grain protectant. Methoprene has been impregnated into a polymer-based packing film to prevent insect infestations of packaged products. The objective of this study was to evaluate fecundity, egg hatchability, and egg-to-adult emergence of the red flour beetle, Tribolium castaneum (Herbst) and warehouse beetle, Trogoderma variabile Ballion, when exposed to methoprene-impregnated packaging. The number of eggs laid by adult beetles, egg hatchability, and egg-to-adult development on the inside and outside surfaces of methoprene-impregnated polyethylene-to-polyethylene (PE-PE) and polyethylene terephthalate-to-polyethylene (PET-PE) packaging were studied at 27 and 32'C and 60% r.h. Inside and outside surfaces of the packaging were cut into discs and fitted into 62 cm2 Petri plates, and 500 mg of flour (T. castaneum) or vanilla shake mix (T. variabile) were added to the arenas. The number of T. variabile eggs laid per female was not significantly different among packaging types. However, methoprene-treated PET-PE packaging reduced the number of T. castaneum eggs laid per female. The polymer packaging generally reduced the percent hatchability of both species. None of the T. castaneum adults emerged on the inside and outside surfaces of the PE-PE treated packages at both temperatures. Only the inside surface of PET-PE packaging resulted in 100% suppression of T. castaneum adult emergence. Egg-to-adult emergence of T. variabile was arrested at the pupal to adult stage transformation at both temperatures on the outside surface of PE-PE packaging, whereas on the inside surface T. variabile were able to complete development to adulthood. The PET-PE packaging greatly reduced the number of normal adults by 87 to 97% when exposed to inside surfaces at both temperatures. Our results show that exposure of eggs to methoprene based packaging can reduce adult emergence of T. castaneum, and to a lesser extent, emergence of T. variable.