警惕四川棉铃虫大发生棉铃虫是国内外棉花生产上的大害虫。在四川，棉铃虫一年发生４—５代，第一代４月上旬至６月中旬，为害小麦、番茄，少数进入棉田；第二代６月中下旬至７月下旬，为害棉花、玉米和一些瓜类的花；第三代７月下旬至８月，集中为害棉花，是棉田内虫口最... Watch out for the occurrence of cotton bollworm in Sichuan Cotton bollworm is a big pest on cotton production at home and abroad. In Sichuan, the occurrence of cotton bollworm 4-5 generation a year, the first generation of early April to mid-June, the damage to wheat, tomatoes, a small number into the cotton field; second half of June to late July, damage to cotton, corn and Some melons of flowers; the third generation in late July to August, focus on the damage of cotton, insects are the most cotton fields ...