ALL OAKS CAN BE INFECTED BY THE FUNGUS THAT CAUSES OAK WILT!
Oak trees in central Texas are placed into one of two groups – red oaks or white oaks. Red oaks are the most susceptible to oak wilt, will typically die within two to four weeks of symptom appearance, and can play a unique role in spreading the disease. Common red oaks in central Texas include: Spanish oak (Quercus buckleyi), Shumard oak (Q. shumardii), and blackjack oak (Q. marilandica).
Oaks in the white oak group are the most resistant of the disease, with variations among the group depending on species. Post oak (Q. stellata), bur oak (Q. marilandica), and Mexican white oak (Q. polymorpha) are very resistant of the disease. These species may exhibit some canopy loss, but rarely die when infected. White shin oak (Q. sinuata var. breviloba), chinquapin oak (Q. muehlenbergii), and Lacey oak (Q. laceyi) can grow in stands with interconnected root systems, enabling the fungus to infect adjacent trees. These species are more resistant of the disease than red or live oaks and usually survive infection with moderate to severe canopy loss, but they can die in large numbers from the disease.
Live oak (Q. fusiformis) is a member of the white oak group and is the most common and abundant oak in central Texas. While live oaks succumb to oak wilt in the greatest numbers, they are intermediate in susceptibility to the disease with a small percentage (< 20%) surviving infection. Live oaks share a common root system. All live oaks in a stand are likely connected to each other and other live oaks as far as 200 feet away. If oak wilt infects one of the trees in the stand, the disease spreads through the common root system to adjacent trees and an oak wilt infection center begins.