Oak trees make great shade trees and offer vibrant color in the fall season. However, oaks can be susceptible to an aggressive tree killing disease called Oak Wilt.
When are my trees at risk and what should I look for?
This disease is a threat to all oaks, but affects red and white oaks differently.
Red Oak Group (red, black, pin and scarlet oaks)
Oak wilt usually is more prevalent during the first half of the summer.
Symptoms early on include wilting, bronzing and shedding of the leaves at the ends of branches in the upper crown of the tree. It is extremely important as soon as you notice your tree is infected to treat it immediately, as this disease in red oaks tends to spread quickly. Bronzing will continue as the fungus progresses. Discolored and green leaves will begin to fall from the tree is large quantities. Fungus mats may also be produced between the bark and the sapwood a year after the tree dies. Typically, a fruity odor will occur from the mat and will attract sap beetles to feed on the mat.
White Oak Group (white, bur, and swamp oaks)
Symptoms are much more variable in white oaks. Symptoms usually develop in the upper crown of the tree like red oaks but tend not to spread so quickly. Typically, they will be limited to one or a few branches at a time. If a white oak is infected, it seldom kills the tree immediately. Leaf discoloration will occur, but more gradually. Streaking of sapwood beneath the bark of infected branches, however, is much more common with white oaks. Spore mats are not produced on white oaks.
Oak Wilt can be managed and prevented in several different ways. Your local arborist will develop a treatment or prevention plan that will be the most effective for your unique property. Find your local arborist here or view the full PDF.