Oak Tree Vascular Disease from Borers

Oak borers can lead to serious vascular diseases.

Oak trees are susceptible to two major borer pests, the red oak borer and the two-lined chestnut borer. Borers cause damage to the tree's bark, leaving it susceptible to secondary infection. Oak borer infestations cause secondary vascular diseases from weakened plant tissue, which can lead to extensive tree damage.

Types

Oak borers are small insects that tunnel in oak bark, which lead to secondary infections of oak wilt and oak decline. Oak wilt is a fungal disease that causes reduced vigor and vascular damage. Oak decline is a disease that affects the vitality of oak. The small holes that oak borers cause are responsible for contributing to the decline, as they reduces the tree's natural defenses to ward off infections.

Identification

Symptoms of oak wilt consist of discoloration, wilt, yellowing and dropping of leaves, and brown discoloration on vascular tissue. Oak decline symptoms consist of branch and twig death, extensive leaf drop and tree death. Tree death occurs within two to five years after first symptoms of design, reports the University of Kentucky Extension.

Control

Remove and destroy oak trees infected with oak wilt to prevent the spread of the disease to nearby oaks, reports the University of Illinois Extension. Control of oak decline consists of improved irrigation with regular watering and pruning dead branches and twigs, which could harbor oak borers or disease. Insecticides can reduce borer populations to prevent bark damage and oak decline.

References

• University of Kentucky Extension: Managing Oak Decline
• United States Department of Agriculture Forest Service: Sudden Oak Death
• University of Illinois Extension: Oak Wilt