Issue 1, May 2, 2023
Botryosphaeria Canker of Dogwood
Neon burst Tartarian dogwood, Travis Cleveland, University of Illinois
My neon burst Tatarian dogwood has been through a lot since I planted it a few years ago. It has been grazed on a few times by the local deer population, hosted a dogwood sawfly convention in 2021, and most recently accommodated several Botryosphaeria cankers. Botryosphaeria canker is a common disease of many landscape trees and shrubs. The cankers tend to be inconspicuous on many plant species. However, the cankers are evident and stand out against the young bright-colored bark of red-stemmed dogwood species.
Symptoms
As with most cankers, the fungus invades through wounds, weak areas of the wood, and possibly through the lenticels. Dark, sunken lesions develop on the stems. The lesion may grow to encircle the stem, killing the cambium as it progresses. The girdled stem dies from the canker to the tip of the branch. The fungus's black, pinhead-sized fruiting bodies are often embedded in the face of the lesion.
Botryosphaeria canker on Tatarian dogwood (Cornus alba), Travis Cleveland, University of Illinois
Disease Management
Remove dead wood during dry weather. Sanitize your pruning between cuts to avoid spreading the pathogen. Drought-stressed plants are prone to the disease. Add a layer of mulch to help conserve soil moisture and provide supplemental irrigation during periods of extended periods of dry weather. Unfortunately, fungicides do not help this situation.
Travis Cleveland
Author:
Travis Cleveland