University of Maryland Extension

Dogwood Anthracnose (Discula) - Trees

diseased dogwood leaves
The early symptoms of discula anthracnose begin in mid to late May as leaf spots with tan or purple borders

This disease, caused by the fungus Discula destructiva, is the most serious disease of dogwoods in the landscape and our forests. The fungus causes dieback or even death of infected trees. The early symptoms begin in mid-to-late May as leaf spots with tan or purple borders. In wet weather, these spots can rapidly enlarge and kill the entire leaf. These blighted, drooping leaves will remain hanging on the branches in wet weather. The disease will then spread from the infected leaves into the twigs and branches and cause dieback of the limbs. If the dieback reaches the main trunk, the entire tree can be killed. To distinguish this disease from other leaf spots such as Elsinoe leaf spot, examine the underside of the leaves for numerous, small tan to brown dots, about the size of a printed period, scattered within the blighted tissue. These dots are the source of spores that will be washed by rain or dew and spread by insects to healthy leaves and neighboring trees. Under severe disease conditions the flower bracts can become spotted.

brown spotted dogwood blooms
Under severe disease conditions, the flower bracts can become spotted.

Management strategies

Both cultural and chemical control strategies are necessary. Prune out all dead or dying twigs and limbs during dry weather. All water sprouts or suckers on trunks and branches should also be removed at this time. In the fall, leaves should be raked up and removed. Remove any dead leaves still attached to the branches. Avoid over-application of fertilizer that results in succulent new growth with greater susceptibility to disease. Avoid digging native trees from the woods and transplanting them into landscapes. This practice can introduce the disease into a neighborhood community that was previously disease-free.

In areas with severe disease, consider planting resistant dogwood species such as kousa dogwood, (Cornus kousa), or hybrids between kousa and flowering dogwood such as 'Celestial', 'Milky Way', 'Stardust', 'Steeple', 'Stellar Pink', and others.

When disease pressure is severe fungicides can be utilized on trees in landscapes in the spring at bud break, followed by additional sprays every 10-14 days until leaves are fully expanded. Trees should also be sprayed once in the fall after the leaves have changed color but before leaf drop. For additional information refer to (PDF) HG 12 IPM Series:Dogwood.

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