Heavy infestation of gouty oak gall (Hymenoptera) on pin oak ( Quercus palustris)įeeding of cynipid wasp larvae (Hymenoptera) caused this cluster of wedge-shaped galls on oak ( Quercus), called pine cone oak gall or lobed oak gall ( Andricus quercusstrobilanus). Like gouty and horned oak galls, this twig gall on white oak ( Quercus alba) is probably caused by a wasp (Hymenoptera) note exit holeĪ particularly large specimen of gouty oak gall (Hymenoptera) on shingle oak ( Quercus imbricaria) Like gouty and horned oak galls, this twig gall on white oak ( Quercus alba) is probably caused by a wasp (Hymenoptera) Gouty oak gall on oak ( Quercus) caused by a wasp (Hymenoptera) Horned oak gall on pin oak ( Quercus palustris) is caused by a type of wasp (Hymenoptera) Heavy infestation of gouty oak gall (Hymenoptera) on oak ( Quercus) Strategy 4 could be considered an organic approach if an organic tree fertilizer is used. Strategies 1 and 2 are strictly organic approaches. See the University of Missouri Extension Guide No. Heavily infested trees may benefit from applications of fertilizer. Therefore, there is no effective way of controlling horned or gouty oak gall.Ĥ. Wasp infestations are unlikely to be controlled by chemical treatment. Maintain the health of the tree by watering during dry periods and fertilizing if needed.ģ. When the galls are small and are just developing on twigs and branches, where possible, prune and destroy the infested plant material. These pests may over winter in twigs, branches, and leaves. Use cultural methods of control to help reduce the wasp. This could give some natural control of the wasp.Ģ. These natural enemies help to reduce the wasps. There are insects that are parasitic and predators that prey on the wasp larvae. Galls are aesthetically not pretty on a tree, but mild infestations won’t hurt the health of the tree. An adult wasp emerges from each horn and another life cycle of wasps begins.ġ. When the larvae reach maturity, the horned galls developed small spines or horns. The galls provide protection, food, and shelter for the developing larvae. The next spring small swellings develop on the twigs and enlarge over the next two or three years. Mated females deposit eggs in young oak twigs. Male and female wasps emerge from these tiny, blister type galls on the leaf vein about mid summer. The females lay eggs on the veins of the oak leaf buds. In early spring a tiny wasp of the cynipidae family emerge from woody stem galls. Wasp can spread to adjacent trees causing them to become infected. Repeated lifecycles of the wasps can result in areas of the tree being covered with galls. At first there are just a few galls throughout the tree. As the gall matures the tumor-like swelling will enlarge to as much as two inches in diameter and becomes woody and discolored. Bark color of young galls are a greenish-brown and bark surfaces are smooth on gouty oak gall and horns on horned oak gall. Young galls are slight, tumor-like swellings on twig growth. The gouty oak twig gall is smooth and can be found on pin, scarlet, red and black oaks. It can be found on pin, scrub, blackjack, and water oaks. The horned oak gall has small horns that protrude from around the circumference of the gall. Chemical control is seldom suggested for management. However, severe infections may bring about the decline of the tree. Most galls are aesthetically not pretty, but normally cause little damage to tree. These deformities are caused by a tiny, non-stinging, wasp which produces a chemical or stimuli inducing the plant to produce large, woody twig galls. Gouty and horned galls are abnormal growths or swellings comprised of plant tissue found on leaves, twigs, or branches. Gouty oak gall on pin oak ( Quercus palustris) caused by a wasp (Hymenoptera)
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