ACTIVITY OF COCONUT-SHELL LIQUID-SMOKE AS AN INSECTICIDE ON THE RICE BROWN PLANTHOPPER (Nilaparvata lugens)

Laboratory trial proved that the genuine of coconut-shell liquid-smoke grade II was very toxic against the rice brown planthopper (Nilaparvata lugens) and phytotoxic to the rice plants. The genuine liquid smoke is very acid (pH 1.2). It could be neutralized (pH 6, 46) by adding it with calcium oxide at rate of 7 grams per 100 ml. LC50 of the neutral coconut-shell liquid-smoke grade II against N. lugens at 24, 48, and 72 hours after treatment were 12.89, 11, and 9.94%, respectively. The concentration rate of 12.5% was feasible to be developed into application dosage at which this concentration rate of neutral liquid smoke was not toxic to the plant.