粘虫是内蒙古自治区河套灌区春小麦最重要的一种害虫。由于地力、作物密度和环境条件的不同,粘虫幼虫的发生密度差异很大。我们1991年调查,小麦田幼虫最少每平方米为9头,最多为85头;1992年最少2头,最多17头。都有部分地块需要药剂防治。只有掌握每块地的幼虫发生期和发生量,才能确定是否用药和用药日期。所以在粘虫发生期 Mythimna separata is the most important pest of spring wheat in the Hetao Irrigation Area of ​​Inner Mongolia Autonomous Region. Owing to differences in soil fertility, crop density and environmental conditions, the occurrence density of armyworm larvae varies greatly. Our survey in 1991 showed that wheat field larvae had a minimum of 9 heads per square meter and a maximum of 85 heads, at least 2 heads in 1992 and a maximum of 17 heads. There are some plots need pharmaceutical control. Only by knowing the occurrence and the amount of larvae on each plot will it be possible to determine whether the drug is given and the date of treatment. So in the occurrence of armyworms