Friday, May 28, 2021

Be aware of oak wilt


It seems like Western New York’s forests are under constant attack, in wars that they can’t win.

In the early 1900s, chestnut trees were all but exterminated from our woodlands by chestnut blight. Dutch elm disease wiped out our impressive stands of elms from the 1950s through the 1980s. Today, millions of ash trees are being decimated by the emerald ash borer. And, mature beech trees will be totally eliminated from our forests in the coming years thanks to beech bark disease.


As our forests reel from those diseases and pests, and are forever changed, more pestilence is piled upon them. The newest of those threats being posed to our woodlands is oak wilt.


It is a serious tree disease that kills thousands of oaks each year in the midwest. It is caused by a fungus -- Ceratocystis fagacearum -- which grows in the water-conducting xylem of host trees, causing the vessels to produce gummy plugs that prevent water transport. As water movement within the tree is slowed, the tree starves to death. The leaves wilt and drop off, and eventually the tree dies.

Until only recently, oak wilt was almost unheard of in New York. There was a small outbreak in Glenville in Schenectady County in 2008 that was contained and then found to have recurred in 2013, which was also contained.


Six times since, though, the wilt reared its ugly head in the Empire State.  


Realize, those are the known occurrences. Others might slip under the radar.


That’s concerning when you consider that the fungus is dangerously close. In 2016, a homeowner in Canandaigua noticed that an oak tree on their property began dying with no identifiable cause. Samples from the tree were sent to the Cornell Plant Disease Diagnostic Clinic, where they tested positive for the fungus that causes the disease. In 2019, a number of infected trees were discovered not far from there in the towns of Bristol and South Bristol.


There is no known treatment to contain and kill the oak wilt fungus other than to remove infected trees, as well as any surrounding host oak trees. The Department of Environmental Conservation took down the trees in question, deployed root disruption, and initiated an emergency order establishing a protective zone prohibiting the movement of oak material out of the immediate area to prevent the fungus from spreading. The DEC is also conducting regular aerial and ground surveys to identify additional trees that may be infected.

It seems like a lot of concern and work, but it’s absolutely necessary to save the forests from the spread of oak wilt. All oaks are susceptible to it, but red oaks die much faster than white oaks. Red oaks can take anywhere from a few weeks to six months to die and they spread the disease quickly. White oaks can take years to die.

Property owners and outdoors enthusiasts are the first line of defense and need to stay aware of any issues impacting oaks in their yards or in the wilds. Symptoms of the disease include browning of leaves starting at the outer edge and progressing inward toward the mid-vein of the leaf; branch dieback that may be visible starting at the top of the canopy and progressing downward; leaves suddenly wilting (hence the name); leaf loss during spring and summer; and fungal spore mats raising and splitting the bark.

The DEC asks that the public report any occurrences where an oak tree dies over a short period of time, especially if it occurs between July and August. You can use the toll-free Forest Health Information Line toll-free at 1.866.640.0652 or send an email with photos and site specifics to

It is very important that we regularly inspect trees for the disease and engage the state if we see something amiss. Not only would oak wilt eliminate some of the most brilliant trees from our fall landscapes, but if oak trees are gone from our forests, especially in the southern tier, it will remove an important food that provides sustenance for a variety of animals from deer to bear to turkeys to squirrels. Years ago, these creatures lost chestnuts. Now, they’re losing beechnuts. If they were to lose acorns, too, there would be a serious, wide-ranging environmental crisis.


So, if you see something, say something.



31 May 2021 Greater Niagara Newspapers and Batavia Daily News

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