Michigan got some shocking news right after the recent holiday. Beech Leaf Disease is officially in Michigan. It was first spotted in St. Clair County. Here in Kent and the surrounding counties, it hasn’t been spotted yet, but that isn’t to say it won’t be here soon.
There still hasn’t been enough research to determine if this is the only way that the disease spreads, but right now it’s looking like a tiny, microscopic worm called Litylenchus crenatate is responsible. Future research will tell us if this worm is the pathogen or if it is carrying the pathogen instead, which could be a fungus.
So how can a little worm cause Beech Leaf Disease?
The nematode, a fancy scientific term for microscopic worms, spends the winter in the leaf buds of Beech trees. This causes damage to the tissue that is irreversible. Because of this overwintering, symptoms don’t usually show up until after budding the following spring. And at that point, its most often too late.
Seeing that the disease doesn’t show any signs or symptoms until budding has completed, there isn’t anything that can be done to protect the trees against it. There isn’t enough research completed to determine how it spreads, what is causing it, and how to stop it. The damage caused also makes the trees susceptible to other diseases. This is where the issue actually lies. Once the tree’s leaf tissues are damaged, and the tree gets a different disease or has other issues, it could die in as little as 6-10 years.
So, what do scientists know about Beech Leaf Disease?
They know most of the signs. Remember that these show up after the disease has been present for quite some time. The signs include, but aren’t limited to, stunted growth, irregular leaf shapes from previous years, dead buds, leaf curling, and damaged leaves. The most obvious sign is the dark stripes on the lower surface between the veins in the leaf, as shown in the image below. It can appear yellow on the upper surface but is more distinct in comparison to other Beech problems.
Since there isn’t a way to eradicate Beech Leaf Disease, what can we all do to help?
Well, we can limit the movement of presumably diseased Beech firewood. This is a general rule for all firewood as well. We can also look out and report on possible areas of infestation. Further, we can limit the movement of Beech in the nursery stock. The nematodes like the habitat of the leaves and buds of nursery stock. And therefore, younger Beech trees are more susceptible to Beech Leaf Disease.
If you suspect Beech Leaf Disease, you should take several pictures, from multiple angles, of the tree and leaves. Also, note the location, date, and time when reporting. Then you can email your findings to DNR-FRD-Forest-Health@Michigan.gov or call 517-284-5895. First, confirm that you are looking at a Beech tree by referring to this handy Beech identification link.
Before reporting, you should look closer to determine if this is Beech Leaf Disease or another common, similar disease in Beech trees. Next, we outline these common misconceptions.
Beech Anthracnose:
This is a caused by a fungus. The fungus that causes Anthracnose in Beech trees is not the same fungus as the ones that cause it in other trees like Oaks or Maples. So, if you have Maple Anthracnose, and a Beech on your property, chances are your Beech probably won’t get Beech Anthracnose unless the proper fungus is introduced. Beech Anthracnose causes early defoliation and can come from a cool, wet, budding season. But the leaf can regrow before the end of the year.
Beech Leaf Curling Aphid:
This is one that is probably most confused with Beech Leaf Disease. The leaves curl and the leaf itself yellows near the curling site. This yellow is on the upper surface, whereas the Beech Leaf Disease is on the lower surface and usually has a more distinct stripping appearance. Beech Leaf Curling Aphid causes minimal damage but can progress over time. It causes the canopies to thin out and eventually die off.
Erineum Patches:
This appears on the upper surface and goes through multiple color changes throughout the foliage season. It also leaves little dimples on the lower leaf surface. Colors change from light yellow, to green, to bright yellow, then gold, red, and then a dark brown. It can cause significant harm to the tree. It also has a felt-like touch to it. This and the color changes is what differs it from Beech Leaf Disease.
Powdery Mildew:
This one is probably least confused with Beech Leaf Disease, as I like to think it looks like baby powder on the leaf. It doesn’t cause too much damage either. Typically, it’s very easy to spot and just causes discoloration and early leaf drop.
In the end, we must take proper care of Michigan’s 37 million Beech trees. If we see a diseased one, we should report it. Sometimes they may need removal. And that can benefit the other trees and Beeches in the area. And we should always trim Beech trees during the proper trimming season. For Beech trees this is in the late winter right before budding season will begin. This is when they are still dormant and causes the least amount of stress on the Beeches. Reach out to us if you have any questions or would like someone to look at your Beech trees!
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