Studies on the leftover standing cotton as carry-over sources of pink bollworm in Sindh [Pakistan]

Several cultural or mechanical practices have been shown individually to reduce over wintering populations of the pink bollworm. It takes a combination of such practices to effectively control this insect during the over wintering stage. The combination of practices may be applied which provide effective control in different parts of the world: I) Harvest the crop as early and in as short a time as possible. ii) Shred stalks immediately after harvest. iii) Plow stalks under immediately, preventing re-growth of new fruiting forms that might provide food for diapausing larvae. iv) Prepare land for planting of the subsequent crop, including pre plant irrigation. v) Plant new crops during a designated planting period that allows for maximum suicidal emergence of moths from over wintering larvae. The pink bollworm does not attack cotton with the same severity in various regions of Sindh. One of the main reasons is the presence of left over bolls, which may be eliminated immediately after harvest. Indeed early crop termination is known to be a successful cultural control strategy as it denies the pink bollworm enough time to develop the diapause generation in the fall and leads to population decline.