Feeding Toxicity of Insecticides against Red Palm Weevil, Rhynchophorus Ferrugineus, (Coleoptera: Dryophthoridae) in a Controlled Environment

Rhynchophorus ferrugineus (Olivier, 1790), often known as the Asian palm weevil or red palm weevil (RPW) (Coleoptera: Curculionidae), had long been considered disruptive to many palm trees (Arecaceae), especially date palms. Observing adults of RPW inside the trunk of palm trees was challenging. Date palm trees provided shelter from bad weather for the larvae that lived and fed within. Finding the red palm weevils required dissecting the palm. Damage could occur to almost every commercially planted date palm variety in the nation, including Aseel, Hillawi, Karbalain, Mozawati, Kechen, and Dhaki. All year round, adult red palm weevils could be found inside palm trees, although they were most active in the summer. The primary method of managing RPW was the frequent use of synthetic pesticides, which were used both preventatively and therapeutically in an effort to lessen RPW damage and spread. In the present study, the soft stem dip method was used to evaluate the toxicity of three different insecticides (clothianidin, trichlorphon (systemic), and fipronil). The results showed that LC50 values with 95% CI (µg/ml) after 72 hours were recorded as 4.096 µg/ml in the case of clothianidin + trichlorfon, representing the highest toxicity. Trichlorphon against 3rd instar larvae of the red palm weevil was more toxic compared to clothianidin and fipronil. The study, therefore, suggested that these insecticides need to be properly included in IPM plans to combat this pest. To test and enhance the efficacy of such pesticides in field settings, more work was necessary.