四代棉铃虫在我省为害期是８月下旬至９月上旬。主要特点是：（１）产卵持续时间长，部位分散。卵大多产在嫩叶背面、边心或苞叶上，少数产在叶背、叶柄或花上，且常与三代虫卵交错，重叠发生。（２）危害青铃，对产量影响极大。（３）受害作物多，除棉花外，还危害玉米、... Four generations of cotton bollworm damage period in our province is from late August to early September. The main features are: (1) spawning a long duration, parts scattered. Egg mostly produced in the back of young leaves, brim or bracts, a few produced in the leaves back, petioles or flowers, and often staggered with the three generations of eggs, overlap occurs. (2) endanger the green bell, great impact on the yield. (3) Victims of crop, in addition to cotton, but also endanger corn, ...