Toxicity of Some Insecticides Against Red Palm Weevil, Rhynchophorus ferrugineus

The red palm weevil (RPW) Rhynchophorus ferrugineus (Coleoptera: Curculionidae) is a key pest of date palm, Phoenix dactylifera in Saudi Arabia and other Middle-Eastern countries. RPW is currently managed in several countries employing a pheromone based Integrated Pest Management (IPM) strategy in which use of insecticides for preventive and curative treatments is essential. In this study, the toxicity of eight insecticides viz. Fipronil^TM, Deltamethrin^TM, Dimethoate^TM, Chlorpyrifos^TM, Methomyl^TM, Methidathion^TM, Fenitrothion^TM and Salut^TM was evaluated at four concentrations per insecticide against adult and larval stages of RPW in the laboratory. Fipronil recorded the least LC 50 values for both adults and larvae, indicating high level of toxicity against RPW, while methomyl registered the highest LC 50 values in spite of a good initial knock down effect. Toxicity among adults and larvae varied between the insecticides tested. However, adult male weevils were more sensitive to the insecticides tested as compared to adult female weevils.