Gloeosporium leaf spot can cause severe defoliation and reduction in yield of blueberry crops.
- Small reddish flecks on young leaves and stems of succulent shoots.
- Leaf and stem flecks do not develop further.
- Large brown lesions (1/2 inch to more than 1 inch across).
- Development of lesions results primarily from infection through hydathodes at the margins of the leaf, and to a lesser extent through wounds. Stem lesions first appear on current season's growth as dark red circular to elliptical lesions around leaf scars. As the lesions enlarge, the affected stems turn brown and eventually become gray and die. On highly susceptible cultivars such as Jersey, the disease results in severe dieback, measuring up to 20 inches.
- Secondary stem lesions can develop from leaf infections by growing through the petiole into the stem, and from bud infections late in the season.
- Cline, W.O. "Bill." Leaf Diseases of Blueberry. Retrieved 01 June 2010.
- Cline, W.O. "Bill" and Gina Fernandez. Suggestions for Establishing a Blueberry Planting in Western North Carolina. Retrieved 15 May 2010.
- North Carolina State University Plant Disease and Insect Clinic. Retrieved 01 May 2010.