Thread Blight of Apple

Thread blight is a fungus disease caused by Corticium stevensii. Primarily, the disease is a problem in poorly managed orchards in the southeastern United States.

Thread blight symptoms are noticeable in early summer. Leaves wilt and turn brown (fig. 1), usually on the interior or shaded portions of the tree. Dead, curled leaves cling to blighted branches, frequently mid-branch, with unaffected leaves remaining on both sides of the diseased area (fig. 2). In well-managed orchards, the disease usually does not …