So What is Bur Oak Blight?

Bur Oak Blight (BOB) is a fungal disease affecting bur oak trees acroos Minnesota, Iowa, and neighboring states. In recent years, this disease has increased in prevalence as spring arrives earlier and brings warmer and wetter weather than our historical averages.

The symptoms of Bur oak blight might look similar to other conditions that afflict oak trees, therefore it is important to work with a qualified arborist to inspect high value oaks for accurate diagnosis and treatment.

Bur oak blight dieback
Dieback seen on leaf of affected Bur oak
Purple–brown lesions on affected leaf

What are the signs and symptoms of Bur oak blight?

Your Bur oak tree may have Bur oak blight if you see the following symptoms:

  • Purple–brown lesions along the middle vein of the leaf
  • Wedge-shaped areas of leaf yellowing or dieback
  • Leaves turning brown and curling
  • Black spots at the base of the leaf stalk
  • Dead leaves remain on the tree through the winter

How do I protect and treat my oak tree?

Bur Oak Blight can be treated with fungicide treatment delivered as an injection into the root flare of the tree. Additional treatments may also be necessary if other conditions are affecting the tree at the same time.

Rainbow Treecare has begun research trials to determine which fungicide treatments will deliver increased effectiveness against BOB. Throughout the long, painstaking process of studying tree conditions, we will continue to update our practices based on the results of our research.

One of our ISA Certified Arborists can help diagnose your Bur oak tree!

Contact us

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