Elm Phloem Necrosis (Elm Yellows)
Phytoplasma sp.
A fatal systemic disease of elm trees caused by a phytoplasma organism, formerly known as elm phloem necrosis in the U.S. and witches' broom in Europe. The pathogen destroys phloem tissue, disrupting nutrient transport and causing rapid tree death.

Identification & Symptoms
What to Look For
Potential Damage
Lifecycle
Signs typically become visible between July and September. Infection begins with rootlet necrosis followed by degeneration of phloem and cambium in roots and lower trunk. Late season infections may not show symptoms until the following spring.
Professional Treatment Approach
Remove and destroy infected trees immediately to prevent spread
Professional diagnosis essential due to similarity to Dutch Elm Disease
No effective cure once symptoms develop
Apply preventive treatments like Arborfos to maintain tree vigor
Monitor for characteristic wintergreen odor in phloem tissue
Vector control may help reduce transmission in some cases
Recommended Mauget Products
Arborfos
Professional-grade treatment specifically effective against elm phloem necrosis (elm yellows).
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Our certified arborists can help you accurately identify tree problems and develop an effective treatment plan using Mauget's proven injection systems.