Lab assay of systemic insecticides on the coconut rhinoceros beetle (Oryctes rhinoceros)

The coconut rhinoceros beetle (CRB, Oryctes rhinoceros L.) is a pest native to Southeast Asian and feeds on various palm species, including coconut palm, oil palm, date palm, and more. It was first detected on Oahu in 2013 and was suspected to have arrived from the South Pacific. Guam has established CRB population since 2007. The beetle attacks the crown of palms causing boreholes in the petioles and v-cuts in fronds. An IPM program to control CRB in Hawaii is urgently needed. This poster reports the lab efficacy of systemic insecticides acephate, imidacloprid, emamectin benzoate, and azadirachtin against adult beetles. All treatments were tested on CRB mortality and paralysis rates in a two-week period (n=10). The first trial included acephate and emamectin benzoate, both at 100ppm, 1000ppm, and control. Acephate showed high mortality at 3, 8, and 14 days after treatment (DAT) at both 100ppm and 1000ppm (100ppm: 20%, 70%, 100%; 1000ppm: 40%, 90%, 90%), while emamectin benzoate was ineffective against adult beetles. The second trial consisted of acephate at 10ppm and 100ppm, azadirachtin at 1000ppm, imidacloprid at 1000ppm, and control. Imidacloprid showed the highest mortality at 3, 7, and 15 DAT (50%, 70%, 90%). Acephate was less effective compared to the first trial (100ppm: 0%, 10% 20%, 10ppm: 10%, 10%, 50%). Azadirachtin showed no difference compared to controls in mortality or behavior. Further testing will determine how efficacy changes at lower concentrations and lower exposure times. If data is available before presentation it will be added to the paper.