Kousa Dogwood Problems

Resistance Level

• The Kousa dogwood (Cornus kousa) is generally considered more resistant to problems posed by pests and disease than its relative, the flowering dogwood (Cornus florida). In fact, the University of Florida Institute of Food and Agricultural Sciences advises that the Kousa dogwood be planted in place of the flowering dogwood as a means of minimizing the likelihood of contracting the disease, Discula anthracnose.

Dogwood Canker

• While the tree is more resistant to most diseases than flowering dogwood, the disease known as dogwood canker can affect it. Dogwood canker is an affliction that causes small and pale leaves. Those same leaves often turn red earlier in the fall, with symptoms of the canker normally appearing only on the infected side of the tree. No chemical control for dogwood canker exists; the best prevention is ensuring that no trunk wounds occur.

Other Dogwood Diseases

• Exceptionally wet soil may bring on a crown canker of the Kousa dogwood that is easily controlled through the application of a fungicide. Another problem, flower and leaf blight brought about by the pathogen Botrytis cinerea, causes flower parts to break apart, fall on leaves and spread the infection. Powdery mildew can also be a concern for the Kousa dogwood, as leaf spot diseases that primarily affect the aesthetic value of the tree.

Pest Problems

• Pest problems of the Kousa dogwood include infestation by the dogwood borer, a moth whose larvae bore into the bark and sapwood of the tree, creating holes in the trunk. Severe infestations of dogwood borer through two seasons have the potential to kill the tree. Other insects that attack the kousa dogwood include the dogwood club-gall midge (Resseliella clavula), a minute fly less than 1/16 of an inch in length and scale insects.