棉铃虫危害银杏苗木的初步观察棉铃虫原为农作物害虫，１９９３年夏季发现严重危害抗虫性强的银杏苗木，其第３、４代幼虫蛀食１－２年生银杏苗顶芽、嫩梢和嫩叶，被害株率高达８４％，顶芽被害率达４６％，严重影响银杏苗木的生长，属林业新害虫。棉铃虫在平度市１年发生... Preliminary observation on the damage of cotton bollworm ginkgo seedlings Helicoverpa armigera was originally a crop pest. In the summer of 1993, it was found that the ginkgo seedlings were highly endangered and highly resistant to insect pests. The third and fourth generation larvae invaded the top buds, Young leaves, the victim strain rate as high as 84%, the top bud damage rate of 46%, seriously affecting the growth of ginkgo seedlings, is a new forestry pests. Cotton bollworm occurred in Pingdu 1 year ...