PHEROMONE BAITED TRAP FOR THE MANAGEMENT OF RED PALM WEEVIL, Rhynchophorus ferrugineus F. (Coleoptera: Curculionidae) POPULATION IN COCONUT PLANTATIONS

Abstract

4-methyl-5-nonanol (ferrugineol), the major component of theaggregation pheromone of Rhynchophorus ferrugineus F. was evaluated as alure for trapping of this pest in coconut plantations in Sri Lanka. Trap design,longevity of ferrugineol in field conditions, and the effect of trapping ondamage incidence of R. ferrugineus were studied. N-pentanol, a knowncompound present in coconut stem volatiles was used in combination offerrugineol in all tested traps. Trap designs tested were; an open plasticbucket, a funnel trap, and a modified metal trap. The open plastic bucket (5 L)baited with ferrugineol-pentanol, which was hung on coconut palm stem at 1.5m, caught significantly more number of adult weevils than ferrugineolpentanolbaited funnel and metal traps. An open plastic bucket trap was sixtimes less expensive than the metal trap currently recommended by theCoconut Research Institute, Sri Lanka. Ferrugineol remained effective as abait for 12 weeks under field conditions. High capture rates of adult R.ferrugineus were obtained in ferrugineol baited open bucket traps inplantations where the initial damage incidence was high. Monthly surveys ofindividual palms during pheromone trapping revealed that a sharp reductionof the number of coconut palms damaged by R. ferrugineus in 10-hectareexperimental blocks. Continuous trapping of weevils with ferrugineol over aperiod of time significantly lowered the infestation of this pest.