dead, dying red oak

Asked August 3, 2014, 1:23 PM EDT

I have red oaks that seem to be dying from a whitish wood-eating larvae that tunnelled between the bark and living part. Could this be the ash borer. One large dead tree with other sick ones on the property.

Polk County Iowa

1 Response

Hello:

Thank you for your message and for contacting Iowa State University Extension & Outreach.

Wood borers between the bark and wood of a tree are common and abundant, but they are typically secondary to other declines in the tree's health and vigor. The emerald ash borer (EAB) is an exception to this rule, but EAB attacks only ash trees (genus Fraxinus). There are no EAB in your oak tree.

But related species, including the two-lined chestnut borer could be in the dead and dying portions of your trees. These borers are secondary and take advantage of weakened trees. Trees are weakened by any of many stresses: Drought, flood, mechanical injury, planted-too-deeply, old age, lightning strike, etc. To learn more about decline in trees, see https://store.extension.iastate.edu/Product/Understanding-Decline-in-Trees-Sustainable-Urban-Landscapes

For more about borers see http://www.ipm.iastate.edu/ipm/info/insects/beetles/flatheaded-borers

Wood borers in trees are difficult to control, and control is not practical in trees that are in severe decline. An arborist or tree care professional can give you an on-site assessment of the condition of your trees.

Thanks.

Donald Lewis