DiseaseMedium Severity

Redwood Branch Canker

A fungal disease affecting all redwood species (Sequoia, Sequoiadendron, Metasequoia) that causes purple spots on needles and cankers that girdle twigs. Most susceptible are trees grown outside their native environment.

Peak Season: Disease development favored by cool, damp spring conditions for spore germination, followed by hot, dry weather that promotes internal growth
Redwood needles showing purple spots and branch canker symptoms

Identification & Symptoms

What to Look For

Purple, circular or oval spots on needles
Spots expanding to cover entire needle
Needles becoming brown and dying
Purplish brown spots at base of needles
Cankers that eventually girdle twigs
Tiny black stromata in discolored areas
Entire distal portion of girdled twigs dies
Brown needles on dead twig portions

Potential Damage

Progressive needle death and browning
Twig girdling leading to branch death
Reduced photosynthetic capacity
Overall tree decline and weakening
Aesthetic damage to tree appearance

Lifecycle

Spores spread from infected leaves or twigs by rain splash during early wet spring rains or fog. Also dispersed by wind. Spores penetrate needles through stomata. Fungus moves from leaf to twig causing cankers. Overwinters as mycelium in infected tissues.

Professional Treatment Approach

1

Remove and destroy infected needles and twigs

2

Improve air circulation around trees

3

Avoid overhead watering

4

Apply appropriate fungicides during susceptible periods

5

Correct phosphorus deficiencies

6

Reduce tree stress factors

Recommended Mauget Products

Fungisol

Professional-grade treatment specifically effective against redwood branch canker.

View Product Details

Mycoject Ultra

Professional-grade treatment specifically effective against redwood branch canker.

View Product Details

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