DiseaseMedium Severity

Anthracnose

Apiognomonia veneta, A. quercina, Gleosporium aridum (fungus)

A fungal disease affecting many tree species, considered a transition between leaf and stem disease. Most severe on sycamore, oak, and ash trees. The disease causes progressive necrosis along leaf veins and can move into twig tissues, forming cankers that may girdle branches.

Peak Season: Most active in warm, rainy or foggy late winter and early spring weather, reduced activity during dry summer months
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Anthracnose damage on sycamore showing characteristic leaf necrosis along veins

Identification & Symptoms

What to Look For

Spring buds fail to mature due to killed tissue
Wilting and death of growing shoots and immature leaves
Progressive necrosis along mid-rib and leaf veins
Small sunken dead areas (cankers) on twigs and branches
Cankers usually occur at leaf scars
Heavy defoliation by late spring or early summer
Infected leaves may remain attached to dead branches
Repeated infections may cause branch dieback

Potential Damage

Defoliation reducing photosynthetic capacity
Twig and branch cankers that can girdle branches
Repeated annual infections may be fatal to trees
Particularly fatal to ash trees with severe infections
Reduced tree vigor and aesthetic value
Increased susceptibility to other stresses

Lifecycle

Fungus overwinters in fruiting bodies in dead leaves, twigs, and canker margins. Becomes active when weather warms in early spring. During warm, wet weather, spores are released and blown or splashed onto emerging shoots and breaking leaf buds. Fungus grows into attacked twigs causing cankers. Disease development is minimal during dry summer months. New infections may occur in fall when infected leaves drop.

Professional Treatment Approach

1

Remove and destroy infected leaves and twigs during dormant season

2

Improve air circulation through proper pruning

3

Avoid overhead irrigation to reduce wet conditions

4

Apply preventive fungicide sprays in early spring

5

Professional assessment for severe infections

6

Clean up fallen leaves to reduce overwintering inoculum

Recommended Mauget Products

Fungisol

Professional-grade treatment specifically effective against anthracnose.

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Tebuject 16

Professional-grade treatment specifically effective against anthracnose.

View Product Details

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