Diseases of Beech Trees: Beech Bark Disease

Diseases of Beech Trees - Beech Bark Disease

Beech bark disease (BBD) is one of the most serious diseases of beech trees that attack beech trees in our area.

What is Beech Bark Disease?

Diseases of Beech Trees - Beech Bark Disease

Beech Bark Disease (BBD) is a fatal infection caused by the deadly combination of an invasive beech scale insect (Cryptococcus fagisuga) and a canker fungus (Neonectria spp.). The beech scale insect feeds on the tree, which causes cracks in the bark. After this, the fungus takes root in the wounds of the now weakened tree. The fungus spreads through the tree and eventually kills it. It now poses a significant threat to beech trees in Ontario.

How dangerous is Beech Bark Disease?

This is one of the most devastating diseases of beech trees. The Invasive Species Centre estimates that 50 to 85% of beech trees infected with Beech Bark Disease will die within 10 years.

Which types of trees are affected by Beech Bark Disease?

Beech Bark Disease affects many of the beech species in Ontario, primarily American beech (Fagus grandifolia) and European beech (F. sylvatica L.).

Diseases of Beech Trees - Beech Bark Disease - European Beech Tree

Damage caused by Beech Bark Disease

This disease can potentially cause widespread damage to the beech population in our area. It causes extensive cankering, tree deformity and eventually death of the trees.

Diseases of Beech Trees - Beech Bark Disease - European Beech Tree

Are your trees safe from pests and tree diseases in your area?

Invasive species such as the Emerald Ash Borer threaten our trees in Toronto and the surrounding regions. Do you know how to protect your trees?

Arborist York Region

Worried about the health of trees on your property in Toronto and the surrounding areas?

Call Sarginson’s Tree Services now (905) 391-8454

Beech Bark Disease Signs

Diseases of Beech Trees - Beech Bark Disease - Beech Scale Nymph

The first noticeable sign is an infestation of the beech scale insect. The insect is tiny (0.5 to 1 mm long) with a yellow body. You can see white woolly wax secreted by the female scale insects on the surface of the bark of the beech. The beech scale insect will proliferate over a number of years. 

The bark may develop small reddish-brown cankers, marking the entry points for the fungus.

Later Signs

Diseases of Beech Trees - Beech Bark Disease fungus

There can be a time lag of several years between infestation by the scale insect and the fungus taking root. You may either see cream coloured patches of fungus growing on the bark or clusters of small reddish fruiting bodies.

There will be scattered cankers on the tree with uneven, blotchy edges. Woundwood and callus build up around these areas beneath the bark, creating a pockmarked and deformed outer look. 

As the fungus spreads, the branches and crown start to die back, worsening over time. The branches and crown progressively dieback, leading to a thinning canopy

Severe infestations will see the overall decline of the tree over time, marked by reduced vigor, and deformity of the stem. It will die from the fungus’s effect or increased susceptibility to other stressors.

Diseases of Beech Trees - Beech Bark Disease fungus

How does Beech Bark Disease spread?

Like many diseases of beech trees, Beech Bark Disease is spread through the movement of affected wood. Beech scale insects can also be spread by wind and on animals. Fungal spores are spread by the wind.

Prevention of Beech Bark Disease

Avoid transporting firewood or wood products from areas with known Beech Bark Disease infestations to prevent the spread of both the beech scale insect and the fungal pathogen that causes diseases of beech trees.

Maintain good tree health, including thinning beech stands to reduce stress on beech trees and promote biodiversity.

When planting beech trees, choose species that show resistance to the scale insect. This may help in preventing or mitigating one of the most severe diseases of beech trees threatening our native trees today.

Beech Bark Disease Treatment

What problems does the emerald ash borer cause

Unfortunately, this is one of those diseases of beech trees for which there is no cure. There is no effective Beech Bark Disease treatment. Removing the scale insects is the only way to prevent the disease from taking root. Once the fungus has arrived in the beech tree, there is nothing that can be done to save the tree, and it should be removed. However, do not remove healthy trees that have survived an infestation.

When should you check your beech trees for Beech Bark Disease signs?

Regularly inspect the bark of beech trees for the presence of scale insects, especially in the early summer when they are active. Be vigilant for the development of small reddish-brown fruiting bodies on the bark in the late Summer or early Fall. These are a sign that the fungus has colonized the tree and it should be removed.

Sarginson's Tree Services Ontario

Get in touch with Sarginson’s if you think you have a problem with Beech bark disease