Leveraging insecticide-treated netting to improve fumigation efficacy for the protection of bulk storage of commodities

Authors: RANABHAT, SABITA - Kansas State University; Brabec, Daniel - Dan; LILLICH, MADISON - Kansas State University; BINGHAM, GEORGINA - University Of Nebraska; Scheff, Deanna; Morrison, William - Rob

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Phosphine fumigation is commonly used for reducing stored product insect populations in bulk storage, however resistance to phosphine is becoming more common and there is a strong need to identify new methods for preventing and reducing infestations. Long-lasting insecticide-incorporated netting (LLIN) has successfully been used to reduce infestation of grain and durable commodities by stored product beetles in the absence of fumigation. In this study, we sought to determine whether using LLIN could prevent stored product insects from entering buckets containing bulk wheat and thus, reduce the need to fumigation. We found that buckets of wheat protected by LLIN (0.3% a-cypermethrin, Carifend, BASF), reduced the number of insects infesting the grain by 83–99% compared to buckets containing insecticide-free netting or no netting. Moreover, the percentage of buckets that reached sufficient population levels to trigger fumigation (e.g., two live insects or 16 insect-damaged kernels per 100 g of wheat) were reduced by 68–91% in buckets protected by LLIN compared to controls. Finally, the use of LLIN reduced the amount of feeding damage to wheat kernels compared to the control treatments and compared to infested grain that had been fumigated with phosphine. Our results demonstrate that LLIN can be deployed to manage insect population levels in bulk grain storage and reduce the need for phosphine fumigations, which can preserve the efficacy of this fumigant and reduce the emergence of phosphine resistant stored product insect populations.

Technical Abstract: Long-lasting insecticide-incorporated netting (LLIN) has successfully been used to impair mobility and prevent infestation by stored product beetles after harvest. Understanding how to integrate LLIN with existing integrated pest management (IPM) tactics such as phosphine fumigation can improve pest management. In this study, we used three 3-MT grain bins, and in each, 60 perforated buckets (e.g., miniature silos) were filled with 500 g of uninfested wheat. Silos were protected by LLIN (0.3% a-cypermethrin, Carifend, BASF), control netting (without insecticide), or no netting (negative control). Half of each treatment was randomly assigned to be fumigated or not. Monthly samples of 100 g of grain from four miniature silos were taken. Dispersing insect life stages were sieved and recorded, while grain quality measures were evaluated. Based on the Federal Grain Inspection Service defect guidelines, if the threshold was met in any bucket during the month, fumigation was triggered for those assigned to that treatment. We recorded and compared the length of protection by each fumigation. Overall, we found that silos protected with LLIN showed insect dispersal and progeny production that was reduced by 83–99% and 89–99%, respectively, compared to positive and negative controls. Additionally, damage in silos was reduced by 37–99% compared to controls. Importantly, the total number of fumigations could be reduced by 68–91% through the use of LLIN compared to controls. Our results demonstrate that LLIN is consistently effective for IPM programs to enhance the efficacy of existing tactics such as phosphine fumigation in bulk storage.