When assessing the health of our street trees, keeping an eye out for signs of trouble is key. One of the more common diseases that affect larger growing tree species is bacterial leaf scorch. Bacterial leaf scorch will eventually affect leaf growth, and can possibly be fatal. There is no cure for the disease, but being on the lookout for noticeable changes in your trees, especially oaks, and calling in experts to test for the disease, can keep your trees happy and healthy in the long term.
So what exactly is bacterial leaf scorch? It is from the bacteria xylella fastidiosa. This bacteria is spread from several types of insects that can be typically found on trees, including leafhoppers and spittlebugs. The bacteria hitches a ride on these insects, and then is transmitted while the insect feeds on the tree.
Sadly, some of our more common large street trees in New Jersey are vulnerable to bacterial leaf scorch. Oaks are the most susceptible, including: pin, red, bur, shingle, and white oaks. Other tree species that are prone to bacterial leaf scorch are: sycamores, sweetgum, American elms, sugar maple, and red maples. All of these trees are important species for the area, so we encourage you to protect your trees as much as possible. If you have these tree species on your property, please keep vigilant and look out for signs of bacterial leaf scorch or other diseases.
Your tree will give you hints that it has been affected with bacterial leaf scorch. As the bacteria spreads through the tree, it begins to kill off the leaves. The dieback begins at the leaf margin, or the border of the leaf. You will see browning start at the edges and work its way inward. There will be a yellow or red strip of dying leaf near the browning area. Dieback will begin to occur, and will happen from year to year. You will sadly see your once vigorous and thriving tree begin to decline and lose canopy. You may also see branches begin to die as the bacterial leaf scorch interferes with new leaf growth. While the look of bacterial leaf scorch is very noticable, a professional will need to be called to evaluate the tree to confirm bacterial leaf scorch. Samples of the tree will need to be taken and analyzed to confirm the presence of the disease.
While there is no cure for the disease, you can keep your tree going and help it bounce back temporarily. There are a variety of products on the market that can be applied to extend the life of your tree, and help it continue to produce leaves. Please consult a licensed tree expert before applying chemicals or for guidance about which treatments will help keep your tree alive. Some local experts we trust are Bartlett Tree Experts and Save a Tree. While bacterial leaf scorch is a damaging and widespread pest, we can catch and treat the disease by being vigilant and calling in the experts when we first see signs of trouble. Hopefully, your tree will still have a long and productive life with proper treatment and care. If you are interested in learning more about bacterial leaf scorch and treatment options, there are a variety of sources online. Missouri Botanical Garden has a good article introducing bacterial leaf scorch, while Rainbow Tree Care goes into symptoms and treatment options. Hopefully, these resources will help expand your knowledge about the trees and how to best protect trees on your property.