Evaluation of methoprene-treated packaging against Trogoderma granarium Everts and Trogoderma inclusum LeConte larval development and packaging penetration or invasion

Authors: Scheff, Deanna; Arthur, Franklin; MYERS, SCOTT - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2019
Publication Date: 12/6/2019
Citation: Scheff, D.S., Arthur, F.H., Myers, S.W. 2019. Evaluation of methoprene-treated packaging against Trogoderma granarium Everts and Trogoderma inclusum LeConte larval development and packaging penetration or invasion. Journal of Stored Products Research. 84:101530. https://doi.org/10.1016/j.jspr.2019.101530.
DOI: https://doi.org/10.1016/j.jspr.2019.101530

Interpretive Summary: Stored product insects are capable of feeding on many different commodities and can infest packaged foods by either chewing through packaging materials or entering through small openings. The larger cabinet beetle and khapra beetle are two highly destructive insect species, capable of causing significant damage to stored products but their ability to infest packaged foods has not been determined. A new packaging technology that incorporates the insect growth regulator, methoprene, was evaluated for its effectiveness against these two pest species. When evaluating four types of packaging material (paper, woven bag, polyethylene-polyethylene (PE-PE), and polyethylene terephthalate-polyethylene (PET-PE)) it was demonstrated that for all packaging materials incorporation of methoprene reduced development of the insects from larvae to adults compared to the controls. The polyethylene with methoprene (PE-PE and PET-PE) had the greatest effectiveness in disrupting development. When effectiveness of materials in preventing invasion of packages was evaluated, PE-PE and PET-PE packaging with methoprene was most effective, with no penetration by larger cabinet beetle and very low infestation by khapra beetle that only occurred when packaging had a small hole. The new packaging technology of incorporating insect growth regulators investigated in this study shows potential for reducing infestation by these two pest species, especially when incorporated into polyethylene packaging and would have application for both domestic or internationals shipment and storage, or by smallholder farmers to store their cereal grains.

Technical Abstract: Trogoderma granarium Everts, the khapra beetle Trogoderma inclusum LeConte, larger cabinet beetle, are highly destructive insect species that can infest a variety of food sources. Methoprene is an insect growth regulator, IGR, and recently has been incorporated into packaging materials as a treatment option for packaged grain, food, birdseed, and feed products, and labeled for this use by the US Environmental Protection Agency (EPA). The objective of this research was to investigate the effect of continual exposure to this novel packaging technology on the development of T. inclusum and T. granarium larvae, and its potential use as a packaging treatment to prevent the penetration or invasion of T. inclusum and T. granarium into food packages. The methoprene-treated packaging incorporated into Kraft paper, woven bag material, polyethylene-polyethylene (PE-PE) material, and a polyethylene terephthalate-polyethylene (PET-PE) material, reduced normal adult emergence of exposed larvae. No normal adult emergence was observed on the inside surface of the PET-PE material. The polymer-based materials were the most effective at preventing penetration or invasion by Trogoderma spp. Only 2% of packages were invaded among all packaging treatment combinations compared to 16.7% invasion of untreated packages. The materials were ranked in effectiveness as Kraft < woven < PET-PE < PE-PE, however, all materials demonstrated significant positive results on Trogoderma spp. This novel packaging could easily be adopted as a packaging control strategy against these and other stored product insects in packaged products destined for commercial, international, and smallholder farm storage of cereal grains, feed, and other food products.