棉花红叶茎枯病是一种生理病害。一般在棉花蕾期开始表现症状,盛发多出现在铃期。棉花生育中期,叶片发病自上而下、由内向外扩展,叶肉褪绿,叶脉仍保持绿色,叶脉间发生黄色斑块,叶质增厚变脆。进入生育后期,病叶先变为黄色,后产生红色斑点,最后全叶变红,叶片干枯脱落。7月7日对 Cotton leaf blight is a physiological disease. The general performance of the symptoms at the beginning of cotton buds, Sheng appeared in the ring more. Cotton mid-term growth, the incidence of leaves from top to bottom, from the inside out, leaf chlorotic, veins remain green, yellow patches between the veins, leaf thickening becomes brittle. Into the later stages of fertility, diseased leaves first become yellow, red spots later, the whole leaves turn red, dry leaves off. July 7 right