Disruption of semiochemical-mediated movement by the immature Trogoderma variabile Baillon and Trogoderma inclusum Le Conte (Coleoptera: Dermestidae) after exposure to long-lasting insecticide netting

Authors: RANABHAT, SABITA - Kansas State University; DOMINGUE, MICHAEL - US Department Of Agriculture (USDA); LEBAR, LUCAS - Kansas State University; BINGHAM, GEORGINA - University Of Nebraska; ZHU, KUN YAN - Kansas State University; Morrison, William - Rob

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2023
Publication Date: 12/14/2023
Citation: Ranabhat, S., Domingue, M.J., Lebar, L., Bingham, G.V., Zhu, K., Morrison III, W.R. 2023. Disruption of semiochemical-mediated movement by the immature Trogoderma variabile Baillon and Trogoderma inclusum Le Conte (Coleoptera: Dermestidae) after exposure to long-lasting insecticide netting. Pest Management Science. 80(4):1702-1716. https://doi.org/10.1002/ps.7903.
DOI: https://doi.org/10.1002/ps.7903

Interpretive Summary: Highly mobile stored product insects may be able to use food cues and insect-produced pheromones to attack agricultural commodities after they are harvested from the field. An important group of stored product insects includes dermestid beetles, to which the cosmopolitan and destructive warehouse beetle and larger cabinet beetle belong. These two species spend the majority of their life cycles as larvae, which are highly mobile. Thus, we wanted to evaluate whether a long-lasting insecticidal netting that contained the insecticide deltamethrin could disrupt the ability of warehouse beetle and larger cabinet beetle from finding pheromones and food cues. Generally, the larvae of both species had difficulty locating pheromones and food after exposure to insecticide netting compared to control netting. However, we found that while movement of larger cabinet beetle larvae was reduced by 50% immediately after exposure to the insecticidal netting, movement of warehouse beetle larvae was not impacted until 24 hr later, when it was reduced by 64%. Larger cabinet beetle may be more resistant to long-lasting insecticide netting than warehouse beetle as negative impacts on behavior did not manifest immediately. Nonetheless, the behavior of both species was impacted and our study suggests the use of insecticide netting may enhance the effectiveness of other concurrent behaviorally-based pest management strategies such as mating disruption when used as part of a comprehensive integrated pest management program in the postharvest environment.

Technical Abstract: Stored product insects are highly mobile and present in the landscape, and they may be able to readily immigrate by tracking plumes of food cues and pheromones. A recent novel preventative IPM tactic to intercept immigrating insects that has been successfully used after harvest is long-lasting 0.4% deltamethrin-incorporated netting (LLIN). However, it is unknown how exposure to LLIN may affect olfaction and orientation to important semiochemicals by stored product insects. In this study, our aims were to evaluate whether exposure to LLIN affected male and female (or mixed sex) populations of T. variabile and T. inclusum movement in the presence of important semiochemicals, including food kairomones and pheromones. We evaluated this with a video-tracking protocol and confirmed volatile emissions with headspace collection coupled with gas chromatography and mass spectrometry (GC/MS). Movement was upregulated 4–6-fold by T. variabile after exposure to insecticide netting compared to control netting, while it was reduced by 28–54% by T. inclusum. Overall, adult T. inclusum olfaction was affected to a greater extent than T. variabile. There were sex-linked differences in the expression of the effects of insecticide netting exposure on olfaction, with pheromonal stimuli more important for males and food and pheromones equally important for females. Our research suggests the use of LLIN may be able to synergize other behaviorally-based strategies when used as part of a comprehensive IPM program.