Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu (India).
*Present address: Department of Agricultural Entomology, Agricultural College. & Research Institute, Madurai -625 104, Tamil Nadu (India).
The moth activity of American bollworm, Heliothis armigera (Hub.), in cotton field was monitored with pheromone traps. The duration of pheromone dispersion from the septa in terms of residual effect to attract the male moths was studied by exposing the pheromone septa for 18 days in cotton field and evaluating them for moth attraction in the laboratory. The septum with 1 mg of pheromone was effective for 11 days in attracting the moths. Carbon free septa were effective up to 13 days. This suggests that the septa should be replaced once in 13 days for moth attraction to be effective in pheromone traps.
