SPRAY COVERAGE AND EFFECTIVENESS OF UNMANNED AERIAL VEHICLE POINT-TOPOINT SPRAYING TECHNOLOGY FOR THE CONTROL OF Oryctes rhinoceros IN IMMATURE OIL PALM

The study aimed to elucidate the characteristics of spray coverage and the effect of spraying in controlling Oryctes rhinoceros beetle (ORB) in immature oil palm using an unmanned aerial vehicle point-to-point (UAVPTP) sprayer.The UAVPTP sprayer was compared to the semi-mechanised FM ORYCT sprayer and the INTER knapsack sprayer.The water-sensitive paper was used as a sampler to determine spray coverage and droplet density and was statistically analysed.Spray volume per palm was determined via a special calibration method, and fresh damage incidences of ORB attack before and after treatment of cypermethrin insecticide using the UAVPTP were conducted to determine the effectiveness of the treatments.The results showed that the spray coverage of UAVPTP at the targeted spears and first spiral of fronds reached a satisfactory level of above 80%.No significant differences were observed in the fresh damage of ORB (F 5,6 =0.85, p>0.05(1st-year-flat);F 5,6 =2.34, p>0.05 (1st-yr-terrace); F 5,6 = 0.67, p>0.05 (2nd-yr-flat); F 5,6 = 1.92, p>0.05 (2nd-yr-terrace)) upon treatments of cypermethrin between the UAVPTP sprayer, FM ORYCT semi-mechanised sprayer or INTER knapsack sprayer after six rounds of spraying treatment at all types of field terrains.The study results provide the theoretical basis and technical support for decision-making in using the UAVPTP sprayer in immature oil palms.