抗虫棉黄萎病是目前抗虫棉的主要病害之一，多在气温摄氏２５℃时发生，其症状为：病株下端叶片边缘发白、发黄、变薄，并逐渐焦干。同时植株上端节间缩短，叶片变小、变薄、逐渐枯黄萎缩死亡。一般一株发病可蔓延到数米之外，并且会连年发生和递增，危害性极大。 防治方法：应 Insect-resistant cotton Verticillium wilt is one of the main diseases of insect-resistant cotton at present, most of them occur when the temperature is 25 ℃. The symptoms are as follows: the edge of the lower leaves of the diseased plants is whitish, yellowish, thinner and gradually dry up. In the meantime, the internodes of plants were shortened, the leaves became smaller, thinner, and gradually atrophy died. A general incidence can be spread to a few meters outside, and will occur year after year and increase, extremely harmful. Prevention methods: should