Horticulture: Dogwood anthracnose spotted
Source: Kim Leonberger, Extension Associate and Nicole Ward Gauthier, Extension Specialist
Anthracnose of dogwood is a common problem in Kentucky. Symptoms on landscape and forest dogwoods often first appear during wet periods in late spring. If left unmanaged, the pathogen spreads, eventually resulting in plant death. Selection of resistant varieties and maintenance of tree health are critical for disease prevention.
Dogwood Anthracnose Facts
• Leaves may develop medium-to-large spots with purple borders or scorched tan blotches that enlarge to kill the entire leaf. Infected petioles and branches exhibit dieback, typically beginning on lower branches. Cankers with a dark brown discoloration under the bark may develop on limbs. The development of trunk sprouts increases.
• Other landscape trees can develop diseases also called anthracnose; however, these result from different fungal pathogens and symptoms vary depending on the type of tree.
• Disease is favored by cool, moist periods. Infection may occur throughout the growing season, as long as conditions are conducive.
• Caused by the fungus Discula destructiva.
• The pathogen survives winter in infected plant tissues, such as leaf debris and cankers.
• Select disease resistant cultivars, such as Oriental dogwood or cultivars developed from the ‘Appalachian’ series.
• Inspect all trees prior to purchase and installation for symptoms.
• Do not transplant forest dogwood into landscapes.
• Prune trees to allow for increased air movement and leaf drying.
• Select good planting sites that allow for adequate sunlight.
• Maintain plant health with proper nutrition, irrigation and the addition of mulch.
• Avoid injuries to trees.
• Prune all dead, dying, or diseased branches from trees.
• Fungicides may be applied preventatively. Contact the Woodford County Extension Office for more information on fungicide use.