Acoustic sensor-based field efficacy evaluation of three different insecticides—Trunk injections against the red palm weevil, Rhynchophorus ferrugineus

Red palm weevil (RPW) is one of the major pests that has caused significant losses in date palm production worldwide in recent years. Effective management of RPW is important to minimizing its impact on date palm yields. Conventional techniques utilized to manage RPW have shown minimal effectiveness. The study aimed to evaluate the efficacy of the insecticides Fipronil, Imidacloprid, and Thiamethoxam against RPW by applying a trunk injection technique in naturally infested date palm fields. Additionally, the study monitored the efficacy of the insecticides for ten months post-treatment using an acoustic sensor. After treatment with Fipronil, Imidacloprid, and Thiamethoxam, the mean burst rate impulses from RPW sound activities inside the date palm trunk was reduced, confirming the gradually mortality of RPW. The RPW impulse burst rate was decreased within 1–2 months post-treatment with these insecticides, while it increased in the control treatment. The results reveal that Fipronil reduced the RPW impulse burst rate from 0.50/s on day 0 to 0.07/s after 50 days post-treatment. In comparison, Imidacloprid reduced the RPW impulse burst rate to 0.07/s after 70 days post-treatment, which indicates a low level of infestation. Similarly, Thiamethoxam reduced the impulse burst rate from 0.97/s on day 0 to 0.08/s after 70 days of treatment. After 4 months of insecticide treatments, the RPW impulse burst rate dropped to zero which indicates the complete cessation of the RPW sound activities. The results suggest that a balloon injector may aid in delivering insecticides directly into the date palm trees, reaching the target more effectively. Furthermore, the acoustic sensor proved to be an effective tool for detecting and monitoring RPW activities in date palms.