Pheromone Chemicals

(Leaf webber) – Distributed throughout India. Is a serious pest of Cabbage, radish, mustard, turnip and other crucifers.

Life cycle

Female moth lays eggs on the lower surface of the leaves. The eggs are laid in masses of 40-100. Larvae hatch out from the eggs in 5-15 days, depending upon the season. The larvae are gregarious in nature and feed on leave surface. Larval period lasts for 24-27 days in summer and 50-52 days in winter. The larva is green in colour when fully grown measures about 2cms in length. It pupates inside the soil by making an earthen cocoon around itself. It has also been found to pupate by making cocoon within the webbed up leaves and flowers of the host plant. The pupal period lasts for 14-40 days depending upon season. During summer the development occurs rapidly

Host plants

Cabbage, radish, mustard, turnip and other crucifers.

Damage

Damage is caused mainly by the caterpillars. The caterpillars form silken web around the leaves. They feed upon the leaves making them completely skeletonized. They also feed on flower buds and bore into pods. They make the vegetable inconsumable by failing with excreta.