TreeIssues

Cluster Cap in Washington

MODERATE

Fungus

Active now in Washington

Cluster Cap is currently active in Washington. Watch your susceptible trees closely and act early.

About Cluster Cap

Cluster Cap observed in the wild. Research-grade iNaturalist observation.

Symptoms to watch for

Treatment options

Fungicide Application

Chemical TreatmentEffectiveness: HIGH

Apply systemic or contact fungicide at the first sign of infection. Repeat applications may be needed during wet weather. Follow label rates and timing.

Sanitation and Pruning

Cultural PracticeEffectiveness: MODERATE

Remove and destroy all infected leaves, branches, and fallen debris. Improve air circulation by thinning dense canopy growth. Sterilize pruning tools.

Soil and Moisture Management

Cultural PracticeEffectiveness: MODERATE

Ensure proper drainage, avoid overwatering, and apply mulch to reduce soil splash. Many fungal pathogens thrive in persistently wet conditions.

Recommended Products & Tools

Helpful supplies for managing Cluster Cap. Always read and follow label directions, and confirm a diagnosis before treating.

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Need help with Cluster Cap in Washington?

Connect with ISA Certified Arborists serving Washington:

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Frequently asked questions

Is Cluster Cap in Washington?

Cluster Cap is currently active in Washington. Watch your susceptible trees closely and act early. It was first recorded here on October 11, 2026.

What does Cluster Cap look like?

How do I treat Cluster Cap?

Options include: Fungicide Application, Sanitation and Pruning, Soil and Moisture Management. Confirm the diagnosis before treating, and consider a certified arborist for high-value trees.