Population dynamics of adult Oryctes rhinoceros and its developmental stages with Oryctes Nudivirus infection in a zero burning replanting area

Zero burning during oil palm replanting has provided plentiful breeding and foraging sites for the oil palm pest, Oryctes rhinoceros . Oryctes Nudivirus is a good biological control agent for Oryctes rhinoceros that can help protect immature oil palms at the early stages of replanting. This study investigated the relationship between population of O. rhinoceros , and the infection level of Oryctes Nudivirus (OrNV), by applying pheromone traps and manually digging of rotten oil palm stem to obtain the developmental stages of O. rhinoceros . Infection of Nudivirus was detected by visual appearance of the midguts. New generation of O. rhinoceros was detected at 6 months after replanting (MAR) where there was the presence of the third instar larvae, L3 at 0.25 l/t (mean per palm heap) and pupae at 0.5 l/t which were present along with young adult beetles at 0.25 l/t. The increase in the adult population from 14 MAR indicates that the second generation of O. rhinoceros has begun. The population of O. rhinoceros was influenced by the presence of Nudivirus, when the infection was highest around 14%, the population of adult beetles decreased to a minimum of 0.92 adults per trapping nightly. A negative correlation between population of O. rhinoceros and infection level of Nudivirus, suggests that the population decreases when there is an increase of Nudivirus. This provides good evidence for further research relating to the use of Nudivirus in controlling population generations of O. rhinoceros in oil palm replanting areas.