1　发生特点及原因1 .1　发生特点。 1 999年冬至 2 0 0 0年春 ,滨州地区气温较低 ,降水较多 ,对棉铃虫越冬极为不利 ,且越冬虫蛹较少。据地区植保站挖蛹调查 ,全区棉铃虫越冬蛹每平方米平均不足 0 .2头 ,许多点未查到虫蛹 ;说明棉铃虫越冬基数低。一代棉铃虫在寄主作物发生较 1 Occurrence characteristics and causes 1 .1 Occurrence characteristics. From the winter of 1999 to the spring of 2000, the temperature in Binzhou was lower and there was more precipitation, which was extremely unfavorable to the overwintering of cotton bollworm and the number of overwintering pupae was less. According to the investigation of digging pupae in the plant protection stations in the region, the overwintering pupae of the cotton bollworm in the whole region averages less than 0.2 on an average per square meter, many of which did not detect the pupae; The generation of cotton bollworm occurred in the host crop