稻纵卷叶螟以幼虫为害稻叶,仅有少数一龄有时取食嫩叶鞘外,叶片是其取食的唯一部位。幼虫为害叶片有两个明显的特点,一是缀叶吐丝作苞,一叶一苞,一苞一虫,二是只啃食叶上表皮和叶肉,留下下表皮,受害处呈明显透明的白条斑。稻纵卷叶螟幼虫共分五龄。笔者在多年的田间测报调查和虫龄分类中发现,不同龄期幼虫所造成的叶片被害状有较明显的差别。因此可从叶片上的不同被害状,识别出为哪一龄幼虫所害。经多年在测报和防治凋查中应用,结果很好,误差甚微。现将用被害状确定龄期的方法要领简述如下:1.稻纵卷叶螟蛾高峰期过后2～3天,当时水稻处于分蘖时,检查稻株心叶靠茎部喇叭 Leaf roller larvae rice larvae infestation, only a few one-year-old feeding sometimes young sheath, leaves the only part of its feeding. The larvae damage leaves have two distinct characteristics, one is decorated with silks for silk bud, a leaf a bud, a bud a worm, the second is only eating leaves on the epidermis and mesophyll, leaving the lower epidermis, the victim was significantly transparent White streaks Rice leafroller larvae are divided into five age groups. The author in many years field survey and worm age classification found that different age larvae caused by the leaves were more obvious differences. So from the different damage on the blade-like, to identify which age larvae harm. After years of application in the newspaper and prevention and control of the investigation, the results are very good with little error. The method of determining the age of the victims will now be outlined as follows: 1. Rice throated leaf moth post 2 to 3 days after the peak, when the rice is tillering, check the heart of rice leaves stem horn