甘蓝夜蛾是酒泉甜菜产区主要害虫,近几年发生面积占实播面积的75％左右。甘蓝夜蛾的食性杂,危害大,一般白天咬根,夜间吃叶。起初将叶面咬成不规则的小孔,继则吃光叶肉,只留叶脉成网状,严重时把根头咬成空洞,藏身于洞内。某些年份已成为甜菜生产中毁灭性虫害。一般使甜菜减产10～20％,含糖率降低0.8 Brassica campestris is the main pest in the beet producing area of ​​Jiuquan. In recent years, the area has accounted for about 75% of the actual sowing area. Cabbage Lantern eating habits, harm, usually during the day bite root, eating leaves at night. At first the leaves bite into irregular holes, then eat light mesophyll, leaving only veins into a mesh, the root bites into a serious hole, hiding in the hole. Certain years have become devastating pests in beet production. The general yield of beet 10% to 20%, reducing the sugar content of 0.8