A novel approach to control red palm weevil, Rhynchophorus ferrugineus, via pheromone-communication disruption through olfactory gene silencing

Abstract: The red palm weevil (RPW) Rhynchophorus ferrugineus (Oliver) is one of the most damaging invasive insect species in the world. When RPWs attack a tree, individual insects can locate the tree with a male aggregation pheromone, and this signal leads to a coordinated massattack that often leads to the death of the palm tree. We used high throughput sequencing of the RPW antennal transcriptome and identified the olfactory gene family proteins involved in the pheromone detection in R. ferrugineus. Further, we used R. ferrugineus olfactory co-receptor (Orco), odorant binding proteins (OBP) and odorant degrading enzyme (ODE) gene silencing and demonstrated that the Orco, OBP and ODE genes can be silenced with RNAi, leading to reduced pheromone detection and communication failure. OBP, ODE and Orco dsRNA injection to the RPW pupae resulted in a significant decline of gene expression compared to noinjection RPW. It has also been shown that reducing the gene expression because of RNAi treatment alters RPW behavior, as confirmed through olfactometer and electroantennography (EAG) assays. With these results we propose pheromone-communication disruption through olfactory gene silencing as a promising approach to control red palm weevil.