使用化学农药防治棉铃虫，只要掌握好“四个适宜”才能取得良好的防治效果。1时间适宜棉铃虫产卵高峰为防治该虫的关键时期。此时用药时间一定要准。用药过早，后或残虫量大；用药过迟，前期虫量多。棉铃虫生育期为半月左右，因此，第一次用药后要及时检查防治效果。同时间隔5 The use of chemical pesticides to control cotton bollworm, as long as a good grasp of the “four appropriate” in order to achieve good control effect. 1 time suitable for cotton bollworm spawning peak for the prevention and control of the pest of the critical period. At this time medication must be accurate. Medication premature, or large amount of residual worms; medication too late, the amount of early worms. Helicoverpa armigera growth period of about half a month, therefore, after the first medication to check the control effect. At the same time interval 5