Assessment and Management of Foliar Diseases Affecting Cotton In Georgia and Texas

Although historically considered of minor importance, foliar diseases affecting cotton have gained increasing attention in recent years.  Diseases like Stemphylium leaf spot, Alternaria leaf spot, and now Corynespora leaf spot have caused concern to many growers and the potential for significant yield loss in affected fields.  In this study research plots were established to assess the efficacy of managing foliar diseases with the use of fungicides and also different rates of potassium fertilizer.  Severity of Stemphylium leaf spot was significantly affected by management of potassium but typically not with use of fungicides.  However, based upon preliminary data, it appears that Corynespora leaf spot can be managed with the use of well-timed fungicide applications.