Oak wilt is a serious fungal disease that is taking over Long Island. Although it can affect all oak trees, the red oaks are much more susceptible to infection and will succumb much faster than the white oaks. The red oaks are defined by their leaves with pointed tips, where as the white oaks have leaves with rounded tips. The fungus infects the cells of the tree’s xylem, interfering with the transportation of water. Red oaks can become infected and die within 6 months. The infection spreads much slower in white oaks.  For them, it can take years for the fungus to become fatal. The speed and voracity of this infection has even led to a strict protective and quarantine zone in all of Suffolk County. They restrict the flow of all oak material, including firewood, out of the county so as to prevent the movement of infected wood.

Oak wilt fungus is spread in 2 ways; by interconnected root systems, and beetle infestations. When a dense population of red oaks begin to flourish, the large roots systems can become tangled. These roots can fuse together in a process known as “grafting”. This allows large groups of oaks to share water and nutrients, as well as the fungus. Large sections of forest have been known to die off as a result of this shared infection.

The infection can also be spread by bark beetles. The spores of the fungus will form just under the bark of an infected and dead tree. These spores secrete an attractive, sweet-smelling odor, which then attracts bark beetles. These hungry bugs will become covered in the spores, which then travel to nearby trees. Beetles are also very fond of newly pruned trees. The open wounds will attract the spore covered beetles, increasing the likelihood of infection.

Regardless of the source of the infection, the symptoms will appear to be the following:

  • Sudden wilt of partially green leaves in the spring and summer.

  • Brown discoloration of  the leaves, starting at the edge and tips, moving inward towards the center.

  • Branch die-back: Starting at the crown and moving downwards.

  • Development of fungal spores beneath the bark.

If you suspect an infection on your property, contact our arborists right away! Our tree care team will advise and treat your oaks with the greatest care. Oaks in need of pruning should be handled only by our professionals who can asses the risk of infection though the fresh cut branches. Frequent sprays will reduce the population of the beetles capable of spreading the fungus. Your arborist can also address any wounds with proper protective dressings, preventing infection from that site. We will also remove and safely dispose of all the infected wood and chips. So as always,

Think Trees?

Think Fox!

You can also contact the DEC Forrest Health division or call 1.866.650.0652