Red palm weevil (Rhynchophorus ferrugineus Olivier): Recent advances

Abstract

Gonzalez, F., S. Kharrat, C. Rodríguez, C. Calvo and A.C. Oehlschlager. 2019. Red palm weevil (Rhynchophorus ferrugineus Olivier): Recent advances. Arab Journal of Plant Protection, 37(2): 178-187. Red palm weevil (RPW, Rhynchophorus ferrugineus) is the most important pest of date and Canary palm in the Middle East, Europe and North Africa. An important management technique has been trapping using the male produced aggregation pheromone, a palm produced kairomone (usually ethyl acetate) and food. The latter needs replacement every 2-4 weeks to maintain good attraction to traps. The use of low service or serviceless traps is viewed by many as the next step in the evolution of the mass trapping technique. Recently a trap sold as the Electrap, has been introduced to the market as a dry, serviceless trap. Its alleged mechanism of action is based on the attraction of insects via electromagnetic radiation. According to the manufacturer, light emitted into the trap is focused into a resonance chamber containing pheromone and kairomone and from this chamber specific frequencies of electromagnetic radiation are emitted which contact the insect and result in its attraction to the trap. Generation of the attractive electromagnetic radiation is supposed to be due to mirrors on the internal sides of the chamber containing the pheromone and kairomone. In this study, we have examined the ElectrapTM with and without mirrors in the chamber and compared the effectiveness of the ElectrapTM vs the standard and modified bucket traps using R. palmarum as a surrogate organism. Our findings indicated that mirrors are not necessary for attraction of R. palmarum to the ElectrapTM and that “serviceless” bucket traps are equally attractive. We also determined that the performance of the ElectrapTM is due to retention of captured palm weevils by the bristle ring inside the conical entry point. Modification of side entry bucket traps by substitution of side entry by a conical entry point on the top results in better weevil retention. Top cone entry bucket traps retain water 3X better than side entry bucket traps. Additionally, we also present data for an "attract and kill" formulation tested against RPW in Malaysian coconut. The attract and kill formulation reduced monitoring trap captures in the test site by over 95% from pre-application and is effective for at least 9 months. Both cases represent new insights and research avenues to develop better control of palm weevils.