Abstract
Thirty-five pheromone traps were arranged in a checkerboard pattern in the test plot (7.5a in surface) of the tea field. In the control plot subjected to the conventional insecticide-spray programme (10a in surface) which was located approximately 150m apart from the test plot, 2 traps were placed at an interval of 15m. The injury by the larvae of the tortrix was estimated by counting the number of folded leaves/m2 of cropped top surface of the tea plants at the mature larval stage of each generation. Efficacy of the mass trapping was apparent in the 1st and 2nd generations when the population density of the insect was still low, the injury of the test plot being 50 and 60% of that of the control plot, respectively.
