Oak Trees in Central Mississippi Face Dual Threat from Caterpillars and Fungus

PEARL, MS – A significant outbreak of variable oak leaf caterpillars, along with the presence of hypoxylon canker, is threatening oak and other hardwood trees in several cities near Central Mississippi, including Flora, Pocahontas, and Raymond. This dual threat poses a serious risk to the health of the region’s trees.

Russell Bozeman, MFC State Forester, stated, “We are aware of the caterpillar damage in and around the Raymond area. We are conducting aerial and ground checks to determine the extent of the damage. Landowners should continue to monitor their forest areas for insect damage and activity.”

Exploiting Weakened Trees

Both the variable oak leaf caterpillar and the hypoxylon canker fungus are native species that typically do not cause significant harm to healthy trees. However, due to drought stress experienced last year, these pests are exploiting weakened trees. The caterpillars’ defoliation further weakens trees, making them more susceptible to other pests and diseases, including the often-fatal hypoxylon canker.

Dr. John J. Riggins, Professor of Forest Health at Mississippi State University and Forest Entomologist for the Mississippi Forestry Commission, warned, “The combination of these two factors is a major concern for the health of our oak trees. We urge residents to monitor their trees closely and take steps to mitigate the damage by promoting tree vigor by whatever means possible.”

Impact of Caterpillars and Fungus

The variable oak leaf caterpillar can cause significant defoliation during outbreaks. Typically green or brown with a lighter-colored stripe down their back, these caterpillars feed on the leaves of oak trees, especially white oaks, although many other deciduous trees can also be affected.

Hypoxylon canker targets stressed or weakened trees, particularly following droughts. The fungus forms cankers, or sunken areas, on the bark, which eventually falls off and is replaced by tan-to-black leathery patches of fungus. These cankers can girdle the tree, cutting off the flow of nutrients and water, ultimately killing the tree.

Residents are encouraged to contact their local Mississippi Forestry Commission specialist or an ISA-certified arborist for more information on how to protect their oak trees.

For further information on Variable Oak Leaf Caterpillars, click here; and Hypoxylon Canker click here.