Oak Gall Wasps or Alien Pods?

As the oak leaves fall in Northeast Florida, some small round balls on leaf surfaces appear due to oak gall wasps laying eggs and releasing enzymes in the leaf tissue. “Alien pods,” proclaimed Jim Messerfish jokingly as to what they were on an Earth Works Facebook post. “Do not swallow them unless you want a chest-burster. “ In fact, they are relatively harmless with over 1400 species of gall wasps that have been identified as targeting oak, hickory, beech, chestnut, maple, elm, citrus, and ornamental trees. There is no universally effective way to get rid of all species of gall wasps while preserving the plant.

“Most cynipids (gall wasps) are not considered economic pests,” according to UF/IFAS. “A notable exception is Dryocosmus kuriphilus Yasumatsu, also called the Asian chestnut gall wasp, which induces galls mostly on leaves and buds of all chestnut species.“ Lack of fire in crowded and stressed native forest stands is believed to contribute to increased seasonal infestation rates. Inspecting plants and burning (where appropriate) or removing affected plant material is a standard best management practice for gall wasps.

Oak Gall Wasps
Oak Gall Wasps

“There are hundreds of different gall wasp species within the Cynipidae family that infect one or all oak tree species,” according to Nature & Garden. “Not all galls result from gall wasp.” Aphids, mites, midges, psyllids, gall flies, fungus, and bacteria can result in galls appearing on leaves, flowers, stems, trunks, and roots.

“In most situations, no controls have been shown to be effective,” according to the University of California. “Certain leaf-galling species may be reduced by insecticides with systemic or translaminar (leaf-penetrating) activity applied in late winter to spring, or by a broad-spectrum, residual insecticide foliar spray timed to coincide with leaf bud break or the early expansion of new leaves. However, gall wasps are unlikely to be well controlled by any single treatment; sometimes insecticide provides no control at all.”

“You might have luck with an imidacloprid application, but otherwise, pull out the dinotefuran (and your wallet),” said Commercial Applicator Joshua Watts on our Facebook post about gall wasps. Earth Works recommends Fertilome Tree and Shrub Drench with Imidacloprid for oak gall wasps. And remember that good soil conditions, proper planting distance from other plants, and fertilization reduce plant stress and susceptibility to pests and diseases.

Fertilome Tree & Shrub Drench

Earth Works encourages you to contact us with your lawn and garden questions in Northeast Florida. For comprehensive solutions to your specific lawn, garden, and landscaping needs, contact Earth Works of Jacksonville online and at 904-996-0712. Earth Works operates a retail Garden Center/Plant Nursery in Jacksonville and provides landscaping, hardscaping, water features, lawn care service, lawn spraying, and drainage solutions.
We proudly serve clients in Northeast Florida, including Jacksonville, Ponte Vedra Beach, Atlantic Beach, Neptune Beach, Jacksonville Beach, Nocatee, St. Johns, Fleming Island, Orange Park, Middleburg, Green Cove Springs, Amelia Island, Fernandina, and St. Augustine.