Evaluations of the new deltamethrin-treated all-in-one hermetic bag for the control of the Khapra beetle, Trogoderma granarium (Everts)

Authors: Scheff, Deanna; BALIOTA, GEORGIA - University Of Thessaly; Domingue, Michael; BINGHAM, GEROGINA - Vestergaard Frandsen Sa; Morrison, William - Rob; ATHANASSIOU, CHRISTOS - University Of Thessaly

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2021
Publication Date: 7/8/2021
Citation: Scheff, D.S., Baliota, G.V., Domingue, M.J., Bingham, G.V., Morrison III, W.R., Athanassiou, C.G. 2021. Evaluations of the new deltamethrin-treated all-in-one hermetic bag for the control of the Khapra beetle, Trogoderma granarium (Everts). Journal of Stored Products Research. 93:101839. https://doi.org/10.1016/j.jspr.2021.101839.
DOI: https://doi.org/10.1016/j.jspr.2021.101839

Interpretive Summary: In many countries in the world, harvested grain is stored in large hermetic or non-hermetic storage bags. Hermetic bags are designed to create a low oxygen (O2) environment in which insects cannot survive. In non-hermetic storage bags, the stored grain is protected from insect penetration or invasion by the material from which the bag is made. Recently insecticide treated (deltamethrin) non-hermetic bags that provide additional protection of stored grain have been developed and adopted. However, the use of a combination of insecticide-treated packaging and hermetic sealing has not been developed or explored. We investigated the potential use of a deltamethrin-treated hermetic bag for the control of the Khapra beetle, one of the worlds most destructive stored product insects and a quarantine pest in the United States. We found that when adults and larvae of the Khapra beetle come into contact with the treated bag surface, more than 40% of adults were unresponsive after 2 d on the treated bags and >86% of larvae after 9 d. Additionally, >75% of larvae exposed to the treated surface for 24 h did not move towards a food bait in wind tunnel tests. We found that wheat in the storage bags that was artificially infested with Khapra beetle had a significant reduction in the number of damage wheat kernels and amount of grain dust and insect waste material accumulated after 2, 6, and 8-weeks of storage in the insecticide treated hermetic bags compared to untreated hermetic bags, despite having a significantly greater larval presence. This research represents the first investigation into the dual function insecticide treated packaging and hermetic storage bags. This new storage bag technology has the potential to be used all over the world to prevent infestation of stored grain and as a preventive measure for the import/export of bagged grain products throughout the world. However, this was a prototype bag technology and there is still the need for further studies on future iterations of this bag material.

Technical Abstract: The khapra beetle, Trogoderma granarium (Everts), is a highly destructive stored product insect that presents a significant threat to stored bagged grain. Hermetic packaging is designed to maintain the quality and safety of stored grain, while continually protecting the grain from insect infestations during storage. The objective of this research was to evaluate a prototype deltamethrin, all-in-one treated hermetic bag on contact efficacy, larval mobility, and the control of T. granarium in artificially infested wheat. The insecticidal activity of the deltamethrin-treated packaging was tested against larvae and adults of T. granarium through contact bioassays. There was a significant reduction in responsive adults after 5 day and >86% of larvae were unresponsive after 9 d of exposure on the treated bag. Trogoderma granarium movement toward a food bait was <10% after a 24 h exposure on the treated bag compared to ~45% of larvae on untreated bag. Lots of 15 kg of wheat were artificially infested with 100 T. granarium larvae and placed inside treated and untreated storage bags, sealed, and stored in a semi-field warehouse, and observed after 2, 6, and 8-weeks for T. granarium survival and grain quality attributes. The weight and number of insect damaged kernels was lower across all storage intervals for grain held in the treated bags, as compared with control bags. Live adult T. granarium were observed at 2 weeks in treated and untreated bags, but there were no live adults observed after 8-weeks of storage in both bags. Moreover, there was significant presence of other stored product species found in grain stored in the control bag. The new prototype hermetic bags maintained positive grain qualities, however more information on the hermetic parameters are needed to understand how some individuals survived.