Look now for tree disease & tree stress

Spring is a good time to check your trees for any signs of stress or disease, according to the New York State Department of Environmental Conservation (DEC).

If you have questions about your trees, email photos and location information to foresthealth@dec.ny.gov or you may contact the Forest Health Diagnostic Lab at 1-866-640-0652.

oak leaf with wilt
Oak leaf with wilt. Photo courtesy New York State Department of Environmental Conservation

Oak wilt 

Don’t prune oak trees in spring!

This is the time when insects that spread the oak wilt fungus are on the move.

Because of recent oak wilt detections in Ontario, the DEC is particularly interested in reports of symptomatic oaks from along the Niagara River and in Western New York. (Other areas of concern are around Canandaigua Lake and the Town of Glenville.)

If your oak trees are turning brown or losing leaves in the spring and summer, please send a description of the symptoms and pictures of the whole tree and leaves to foresthealth@dec.ny.gov.  

Beetles can pick up spores of the fungus that causes oak wilt. The beetles are attracted to wounds on the oak trees and can spread the fungus on the wound. The tree will become infected and can die within months—that’s why you shouldn’t prune oak trees now.

leaves with beech leaf disease
Striping is one of the symptoms of beech leaf disease. Photo courtesy Ministry of Natural Resources and Forestry (Ontario)

Learn more about oak wilt here.

Beech leaf disease 

Since 2022, beech leaf disease (BLD) has been identified in in all eight counties of Western New York. View the beech leaf disease map.

There is no known treatment for infected trees. BLD can kill mature beech trees in 6–10 years and young trees in as little as 2–3 years.

You can help by reporting potential BLD infections. See what to look for and how to report here.

On this page you can see other look-alike diseases to help you differentiate them from BLD.

trees with white pine needle disease
White pine needle disease will cause needles to turn brown and fall off in spring and summer. Photo courtesy New York State Department of Environmental Conservation

White pine needle disease 

White pine needle disease (WPND) is a disease complex that causes the needles of the white pine to turn brown and fall off in the spring and summer.

Brown pine needles are normal in the fall, but if you’re seeing brown needles this spring, please send a description of the symptoms and pictures of the whole tree and needles to foresthealth@dec.ny.gov

Tree stress

Some signs of stress to look out for include: 

  • Large areas of the canopy that didn’t leaf out or that have dead branches.
  • Leaves that seem small, shriveled, or damaged and do not expand properly.
  • Wounds, large areas of loose bark or signs of insect or fungal damage around the base and on the trunk.

If you see some small signs of stress, that’s okay. Trees are resilient and can bounce back from many stresses over time.

You can often help reduce tree stress by mulching properly, watering during dry periods and avoiding compacting or moving soil around the roots.

However, in cases where many stresses have built up over time, when a large part of the tree is damaged, or if you’re concerned the tree may be a hazard to people, structures, or utilities, it’s time to contact a certified arborist. Learn how to find a certified arborist in your area.

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