Jumping Oak Gall Causing Leaf Damage to White Oak Trees in Arkansas

Staff Writer

LITTLE ROCK, ARK. – Leaf damage has been confirmed in clusters of white oak trees in north and central Arkansas areas due to Jumping Oak Gall, or small plant growths caused by tiny, stingless wasps. In most cases galls do not cause permanent damage or tree mortality. The largest infestations have been confirmed in Crawford, Franklin, Pope and Van Buren Counties, though may also be present throughout north and central Arkansas counties and the Ozark-St. Francis National Forests.
Jumping oak gall forms on the underside of white oak leaves. Each instance contains a single wasp larva that feeds on the inner lining of the gall. This presence causes the upper surface of the leaf to lighten in color and form a kind of blister that is often ringed with a yellow halo. Severe infestations will cause the leaf tips to turn brown. Heavily damaged leaves may curl and fall from the tree, thereby damaging the entire tree top. Fallen galls are sometimes observed to “jump” due to vigorous movements of larvae within.
Native insects, like the wasps inside the white oak jumping galls, have natural biocontrol throughout this region – which means that they will be common one year and due to climate, natural predators, or other conditions, will not return again for several years after. This same gall was most recently noticed in Arkansas in 2010. By contrast, non-native, invasive insect species like the Emerald Ash Borer, have a long-term presence in a region and create permanent, devastating damage to plants and trees.
Trees can become stressed due to defoliation; in urban areas, proper tree care such as mulching, watering during drought, and avoiding wounds due to lawnmowers and trimmers are beneficial to a tree’s healing process and overall health. Should residents notice damaged trees not re-leafing or want a positive identification of Jumping Oak Gall, they can call local AFC Foresters for assistance. Find contact information for all county foresters at www.forestry.arkansas.gov/contactus. Contact Forest Health Specialist Chandler Barton at (501) 297-1581 or chandler.barton@arkansas.gov.
The mission of the Arkansas Forestry Commission is to protect Arkansas’s forests, and those who enjoy them, from wild land fire and natural hazards while promoting rural and urban forest health, stewardship, development, and conservation for all generations of Arkansans. To report wildfires, call (1800)468-8834. To report prescribed burns, call (1800) 830-8015. For more information about the Arkansas Forestry Commission, visit www.forestry.arkansas.gov.