Target Spot Caused By Corynespora Cassiicola Confirmation in Tennessee Cotton

Upland cotton (Gossypium hirsutum) is one of the most important crops to the state of Tennessee and the state’s production consistently ranks within the top ten in the United States. In August of 2013 and 2014, dryland cotton plants infected with foliar spots were observed in Madison County, Tennessee. Symptoms were first noticed in the lower portions of the crop canopy as roughly circular, brick red spots with dark borders that led to the formation of irregular to circular lesions with tan to light brown centers. Individual lesions continued to enlarge forming concentric rings of alternating light and dark brown bands from within the original spot, comparable to the appearance of a target. In 2014, symptoms continued to spread higher in the crop canopy, causing premature defoliation later in the growing season. The lesions were initially diagnosed as Target Spot caused by the fungal agent Corynespora cassiicola based on signs and symptoms previously reported in upland cotton. To our knowledge, this is the first report of Target Spot in Tennessee cotton. Confirmation and analysis of this pathogen will enhance the deployment of management strategies for Tennessee cotton producers before incidence becomes more prevalent.