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研究表明，土壤湿度在相当大的范围内对棉铃虫的化蛹及羽化影响不大。土壤相对含水量在９０％以下时，棉铃虫化蛹率一般在９０％以上，羽化率在８０％以上，最适为４０％左右。降雨对棉铃虫入土化蛹的不同时段影响有差异，雨水浸湿土壤，对入土后尚未化蛹的幼虫影响很大，其死亡率接近１００％。化蛹后蛹的死亡率则主要取决于浸水时间的长短。浸水１～２ｄ，对蛹的影响较小，羽化率一般在５０％以上；浸水３～４ｄ，羽化率则一般低于２０％。对近年棉铃虫发生的实况分析也表明，棉铃虫入土时降大雨，后期蛾消长曲线上相应的位置将出现一个低谷。灌水灭蛹以幼虫入土高峰期最为经济有效。
Studies have shown that soil moisture in a considerable range of the bollworm pupation and feathering little effect. When the soil relative water content is below 90%, the pupation rate of H. armigera is more than 90%, the emergence rate is more than 80% and the optimum is about 40%. Rainfall had different effects on the pupae inoculated with cotton bollworm at different time periods. Rainwater soaked the soil, which had a great influence on the larvae that had not been pupated after the soil was infested, with a mortality rate close to 100%. Pupa pupation after the death rate is mainly dependent on the length of immersion time. Water immersion 1 ~ 2d, little impact on the pupa, the emergence rate of more than 50%; 3 ~ 4d, the emergence rate is generally less than 20%. The live analysis of the occurrence of cotton bollworm in recent years also showed that when the cotton bollworm into the soil when the heavy rain, moth growth and decline in the corresponding position on the post-emergence of a low trough. Watering pupae larvae into the soil at the peak of the most cost-effective.