Control of rhinoceros beetle in endemic outbreak areas

In new planting, or replanting, of oil palms in Malaysia, burning is prohibited, thus making the rotted plant residues conducive for Oryctes rhinoceros (Coleoptera: Scarabaeidae) breeding. Damage by newly emerged adults can cause yield losses up to 25%.  In high risk, or outbreak areas, early trapping using the aggregating pheromone ethyl-4-methyloctanoate at the field boundaries hinders migrating adults from coming into the replanted blocks.  Installation of one trap per two hectares is practiced either for adult mass trapping or for monitoring purposes. The biological control agent Metarhizium anisopliae can be applied by various methods, but the artificial breeding site (ABS) method is preferable and is more economic than other techniques.  The ABS integrates a pheromone trap to attract adults to the breeding site, followed by later spraying with the fungus.  High numbers of dead infected beetles, especially the larvae, significantly reduce the emergence of next generation adults. The Oryctes nudivirus (OrNV) is another biological agent which affects the longevity of immature and adult stages, and of the fecundity of the female beetle.  Impact of the release of OrNV on beetle populations is only found in young replanted areas. Census to determine a damage threshold level is carried out on a regular basis starting as early 6 months after planting up to 3 years after replanting.  When the damage level is more than 10%, planters prefer to use cypermethrin to control the pest. Spraying of this chemical on young palms has significantly reduced palm damage as early 11 weeks after spraying.