STUDIES ON THE SEX-PHEROMONE OF THE DIAMONDBACK MOTH PLUTELLA-XYLOSTELLA (LEPIDOPTERA, YPONOMEUTIDAE) IN INDIA

Marked male moths of Plutella xylostella (Linnaeus) released at up to 12 m from a sticky delta trap baited with synthetic pheromone, were ca ught in significantly higher numbers than moths released at greater di stances, both in downwind and upwind directions, from the traps. Maxim um catches were obtained when the traps were set at 30 cm above the cr op level. Continued exposure of septa in the field led to a progressiv e reduction in catches, and catches were significantly reduced after 2 8 days. Newly emerged virgin female moths attracted significantly more male moths than one day old or older virgin female moths. Five day ol d virgin females attracted no male moths. When virgin females were use d as a bait in the field, the peak catch of males was between 1600 and 1800 h. Tests at two field locations revealed that, at the concentrat ion tested, synthetic sex pheromone attracted a similar number of moth s to the number attracted by 10 virgin females in delta traps, and sig nificantly more than 8, or fewer virgin females.