水稻叶部病害的种类较多,有时几种病害同时在叶部出现,很容易混淆,不能正确区别病害类型,就不能对症用药,及时控制病害的发生与危害。现将水稻生产中常见的几种叶部病害的主要症状介绍如下:稻瘟病。叶片上出现较大的梭形病斑,粗看病斑呈褐色,细看则分为三层:外围有黄晕、边缘层呈褐色,中央为灰白色。典型症状:病斑两头有褐色坏死线 Rice leaf disease more species, and sometimes several diseases appear in the leaves at the same time, it is easy to confuse, can not correctly distinguish the type of disease, it can not symptomatic medication, timely control of disease occurrence and harm. Now the main symptoms of several leaf diseases common in rice production are as follows: rice blast. Larger spindle-shaped lesions appear on the leaves, coarse spots looking brown, look thin is divided into three layers: the outer periphery of the yellow halo, the edge of the layer was brown, the central gray. Typical symptoms: lesions have brown necrotic lines at both ends