Occurrence of Dogwood Anthracnose, Spot Anthracnose, and Botrytis Blight in Native Stands of Flowering Dogwood in North Alabama

Abstract

Abstract In North Alabama, dogwood anthracnose (Discula destructiva) was the most common and damaging disease identified in stands of native flowering dogwood (Cornus florida). In the spring of 1992 and 1993, this disease was observed at 59% and 64%, respectively, of the forest and park sites surveyed. Highest incidence and severity of dogwood anthracnose was recorded in the Appalachian Mountains and adjoining foothills of the Piedmont at elevations of 372 to 558 m (1200 to 1800 ft) in the northeastern corner of Alabama near Georgia and Tennessee. At selected sites in Cherokee, Cleburne, DeKalb, Jackson, and Madison Counties, approximately 90% to 100% of the trees examined displayed diagnostic symptoms of dogwood anthracnose. Extensive blighting of the leaves, shoot dieback, epicormic shoot formation, and sometimes tree death were noted. Lower levels of anthracnose damage were recorded on trees in several additional counties in northeast Alabama. Survey results indicate that this disease has not spread onto flowering dogwood in other counties in North Alabama. Spot anthracnose (Elsinoe corni) and Botrytis blight (Botrytis cinerea) were found far less frequently and at fewer locations on flowering dogwood than dogwood anthracnose. Typically, damage attributed to either disease was unobtrusive and of little threat to tree health.