Red Maple Black Oozing: Phytophthora Bleeding Canker, Complex Management

Young red maple: black oozing trunk spots in heat, ants love it, some leaf scorch/spotting.

Leaf Scorch = Stress

Drought, transplant shock, etc.

Oozing Causes

• Insects
• Phytophthora bleeding canker — endemic, causes trunk cankers in maples
• Bacterial wetwood
• Other fungi

Diagnosis

Chisel 2″ square bark piece from ooze → overnight cold pack to Ag Lab for Phytophthora test.

Management (If Phytophthora)

• Trunk spray Agri-Phos (uncertain efficacy)
• Drip irrigation, no root disturbance
• Slow branch dieback

Hard to diagnose/control. Good culture helps.