DiseaseLow Severity

Elm Dieback (Vermicularia)

Vermicularia ipomearum

A fungal disease causing small, girdling cankers on elm twigs that lead to limited dieback. While not highly significant, it creates aesthetic concerns with its characteristic black fruiting structures.

Peak Season: Most active in wet spring conditions which favor disease development. Cankers are most visible in late spring.
View Treatment OptionsRecommended Products
Elm dieback showing characteristic branch death and canker symptoms

Identification & Symptoms

What to Look For

Small, black, girdling cankers on small twigs
Limited dieback of affected twigs
Tiny, hairy, black fruiting structures (pycnidia) at edges of cankers
Small, round, grayish cankers on twigs in late spring
Cankers enlarge each season until twigs are girdled
Needles appear dry and straw-like on affected branches

Potential Damage

Small twig dieback
Aesthetic damage from black cankers
Gradual weakening of branch structure
Limited overall tree health impact

Lifecycle

The pycnidium is globose, leathery black, with dark-colored bristles. Conidia are elongate, single-celled, and slightly curved. They are produced abundantly during the growing season, reinfecting the tree through spore dispersal.

Professional Treatment Approach

1

Prune and destroy infected twigs and branches during dry weather

2

Apply preventive fungicide treatments with Fungisol during wet spring periods

3

Improve air circulation around trees through proper pruning

4

Avoid overhead watering that promotes fungal growth

5

Monitor trees during wet spring conditions for early detection

Recommended Mauget Products

Fungisol

Professional-grade treatment specifically effective against elm dieback (vermicularia).

View Product Details

Arborfos

Professional-grade treatment specifically effective against elm dieback (vermicularia).

View Product Details

Need Professional Diagnosis?

Our certified arborists can help you accurately identify tree problems and develop an effective treatment plan using Mauget's proven injection systems.

Schedule ConsultationUse Diagnostic Tool