棉大卷叶螟Sylepta dergogata Fabr.是棉田中重要的食叶类害虫。幼虫食量大,为害严重时,棉叶全被吃光,仅留下茎枝残叶,不能开花结铃。正确地识别棉大卷叶螟幼虫龄期,对于提高预测预报水平和防治效果是非常必要的。 Sylepta dergogata Fabr. Is an important leaf-like pest in cotton fields. Large larvae food intake, serious damage, the cotton was eaten, leaving only stalk leaves, can not flowering bell. Accurately identify the age of cotton leaf roller larvae, in order to improve the level of forecasting and prevention and control is very necessary.