Do you have an Oak tree in your yard with a few brown leafy branches/twigs throughout?  Or maybe you’ve spotted this while out driving around and wondered what this is.  It’s called Botryosphaeria twig canker and is a very common problem- especially in wet years.  It is very visual and easy to spot.  We believe sound cultural practices which promote tree health, like root feeding/irrigating in the summer and maintaining a 3 inch layer of mulch around the tree are the best defense for this problem.

The Iowa State University Extension Service has a great article addressing this issue:

Botryosphaeria twig canker is probably responsible for the brown leafy twigs in the red oak.  Botryosphaeria twig canker (a fungal disease) impairs the flow of water and nutrients in the branch and eventually girdles the twig, causing it to wilt and die.  Dieback usually extends only 4 to 6 inches inward from the branch tips. The dead twigs typically appear in mid to late summer and are scattered throughout the tree.  Botryosphaeria twig canker is most commonly seen in red and pin oaks, but also occurs in other oaks.  In general, Botryosphaeria twig canker causes minimal damage to otherwise healthy oak trees.  Sound cultural practices, which promote tree health, are the best defense against Botryosphaeria twig canker.

The twig pruner and twig girdler are two long-horned beetles that can also cause branch dieback in oaks.  Branch tips destroyed by the twig pruner and twig girdler eventually break off and fall from trees.  In contrast, the dead twigs produced by Botryosphaeria twig canker remain in the tree through fall.  Botryosphaeria twig canker differs from oak wilt in that only the tips of branches are affected.  Oak wilt affects whole branches.

To view the complete article, please visit:  https://www.extension.iastate.edu/news/yard-and-garden-oak-tree-abnormalities