灾害性棉病死苗,发生范围广,危害性大,是棉花生产上一个老大难问题。为了防灾保产,根据长安、乾县、临潼、大荔等县病虫测报资料和各主产棉县市的有关灾情调查,以及笔者蹲点试验观察,试对这一问题探讨如下: 一、发生规律棉苗枯死每年都或多或少有不同程度的发生;而灾害性棉病死苗 Catastrophic cotton dead seedlings, occurred in a wide range of harmful, is a long-standing problem in cotton production. For disaster prevention and protection of production, according to the survey data of pests and diseases of Chang’an, Ganxian, Lintong and Dali counties and the relevant disaster investigation in major cotton producing counties and cities, Regular occurrence of cotton seedling withered more or less each year to varying degrees of occurrence; and disaster cotton seedlings dead