Botryosphaeria Canker: Atlanta Diagnosis & Management Guide

What Is Botryosphaeria Canker?

Botryosphaeria canker is caused by fungi in the Botryosphaeria genus and is one of the most common and destructive canker diseases affecting ornamental and shade trees in the Atlanta area. The pathogen is opportunistic — it lives on bark surfaces of most trees without causing harm, but invades aggressively when a tree is weakened by drought, heat stress, poor planting practices, or physical wounds. In metro Atlanta, this disease is the single most common killer of eastern redbud, and it frequently damages dogwoods, Yoshino cherries, sweetgums, and river birches.

How to Identify Botryosphaeria Canker

Look for these telltale signs on your trees:

• Dark, sunken cankers: Oval to elongated sunken areas form on branches and trunks. The bark over these areas may appear darker than surrounding healthy tissue.
• Branch tip dieback: Shoots and branch tips die back progressively, working from the outer canopy inward as the fungus girdles branches.
• Bark cracking and peeling: As cankers expand, bark splits and peels away, sometimes revealing darkened wood beneath.
• Oozing sap: Gummy, amber to dark-colored sap may weep from canker margins, especially on cherries and redbuds.

Treatment & Prevention

There is no chemical cure for Botryosphaeria canker. Management depends entirely on cultural practices and timely pruning:

• Prune infected branches: Cut at least 12 inches below the visible margin of any canker, making cuts into healthy wood. Sterilize pruning tools between cuts with 70-percent rubbing alcohol.
• Water during drought: Atlanta's summer droughts are the primary trigger for outbreaks. Deep watering during dry spells keeps trees vigorous and resistant to infection.
• Mulch properly: Maintain a 3- to 4-inch layer of organic mulch over the root zone to conserve moisture and moderate soil temperature. Keep mulch away from the trunk.
• Avoid wounding: Protect trunks from mower and string-trimmer damage, which creates entry points for the fungus.

When to Call an Arborist

If cankers are present on the main trunk or multiple scaffold branches, the tree may be in irreversible decline. An ISA-certified arborist can assess the extent of infection and recommend whether pruning, plant health care, or removal is the best course of action. Call EastLake Tree Services at 404-850-1174 or request a free quote.