As mentioned, leaf galls are abnormal cell growths on branches or leaves. They can appear as single bumps or a collection of complicated structures, and come in a wide array of colors, from plain brown to bright reds and oranges. They can form where insects eat or lay their eggs, because the interaction between the chemical stimuli and the plants hormones. They can also form at sites of infection caused by bacteria, fungi, and viruses.
Most of the time, leaf galls are not a serious problem and will not kill a tree. Infested leaves can still carry out photosynthesis at the normal rate of production. However, some cases can be serious enough to require professional intervention, such as Gouty Oak and Horned Oak gall. Also, if plants are smaller, leaf galls may stunt their growth because the plant’s water and nutrient distribution system is affected.
Tips for Managing Leaf Galls:
Do not do anything and just live with the condition. Because the presence of leaf galls is not always detrimental to a tree, it is best to just ignore them and go on with your life. Although unappealing, they will not kill your tree.
Try chemical sprays. Using chemical sprays is best suited for small trees that has poor health or has been free of foliage for several years. You must be careful using chemical sprays since they can actually kill helpful insects that keep galls away.
Tree care is always effective. Raking fallen leaves in a timely manner and pruning infested twigs and branches can be an effective method for controlling leaf galls. Talk to your local tree care contractor about the necessary tree services for your landscape.