What’s Eating My Tree: Spring Tree Diseases To Watch Out For

As Michiganders, we welcome the sight of new green buds or blooming flowers on our trees. They herald the return of spring. Unfortunately, this period is also when tree diseases and critters emerge too. Thankfully, if you catch these tree diseases early, injection treatment or spray from Alpine Tree and Lawn Care will zap them!

Common Tree Pests And Diseases

Leaf Spot

Like many of the tree diseases we’ll discuss, leaf spot is caused by fungus. It’s worth noting that a few infected leaves is not the end of the world and may not require treatment. But if you notice a large portion of leaves is affected, that’s when you should send in the cavalry. The exception to this is if you have a younger tree. Older, more established trees are hardier, but younger trees are more susceptible to leaf spot. So if you have a sapling that’s got even one leaf spot, you should give us a call in this instance. When leaf spot progresses, it can cause trees to have black, brown, or tan spots, and the infected leaves often break off well before autumn.

Tree Scale

Scale looks like how it sounds: a flat organism that makes your tree’s bark look scaley, almost like the bottom of a ship that’s covered in barnacles. The scale is typically brown, gray, or white. They often get mistaken for knots on the tree, which is why many people don’t realize they have a problem at first. This critter likes to latch onto the trees and drink from the sap. They can be “soft” scale, which is flatter, or “armored” scale. Armored scale bugs have a shell on their backs. As you can imagine, the tree will slowly lose vitality as its sap is drained. Leaves can turn color and die off.


There are several varieties of tree mites in Michigan. One of the most common we see is the spider mite. Spider mites are incredibly tiny, and you might not even notice them on the trees themselves. However, if you see brown branches or dead patches of needles on your evergreen trees, you might have mites. Take a piece of white paper and hold it under the infected area. Give the tree a shake and see if any mites fall onto the paper. Spider mite eggs are tiny, red, and circular. Adult spruce spider mites are elliptical in shape and are usually green, dark green, or almost black. They are never white, pink, or light red – any mites of these colors are actually beneficial for your trees.

Emerald Ash Borer

The Emerald Ash Borer is probably the most infamous tree pest in the Mitten. The insects themselves are a metallic emerald green – hence their name. But if you don’t see the bugs themselves, you may notice the “D” shaped holes they leave behind as they bore into your ash tree. If caught early, you may be able to save your tree from being chopped down. Like other tree diseases, the emerald ash borer causes branches to die off and the bark to become flaky.

Oak Wilt

Just as the emerald ash borer only attacks ash trees, oak wilt only impacts oaks. It’s becoming a growing concern here in Michigan. Caused by a fungus, oak wilt enters trees when they have been “wounded” somehow. For example, if you prune a tree branch. In fact, arborists at Michigan State University have advised against pruning or trimming oaks from April 15 – July 15. The biggest sign of oak wilt is the discoloration of the leaves. They will turn brown and blotchy, almost like the leaves were painted using brown and green watercolor paints. Often, the base of the leaves remains green.

Apple Scab

Another day, another tree fungus. Apple scab is the bane of fruit trees here in Michigan. It’s a fungus that ruins not only the fruit but the leaves as well. And no, you can’t eat those apples once they’ve been infected. Apple scab produces olive-green spots on the leaves and creates a border that turns dark brown or black with time. This is not a subtle disease, so if you notice your apples look deformed or just plain gross, it very well could be apple scab.


Aphids are annoying for two reasons. Firstly, they feed on plants by sucking out the leaves’ juices, stems, pretty much whatever they can get their little hands on. As we’ve already discussed with other bugs, like tree scale, this can cause the tree to lose leaves and negatively impact its overall health. Now, aphids are incredibly common, so if you see one leaf crawling with aphids, there’s no need to panic. But if you see many leaves covered in aphids, and your tree begins to lose those leaves, then it’s time to call in the help of a tree care service. The second reason aphids are so annoying is their activity can invite other problems. They excrete a sticky liquid called “honeydew,” which is attractive to microbes like mold. There are many aphids species, but the most common ones you’ll find in Michigan are tiny and a neon green color – perfect for blending in with leaves. Also, they often cling to the undersides of leaves, which helps them avoid detection. So if you suspect you’ve got aphids, leave no leaf unturned.

Hire A Professional Tree Service Near Oakland County, MI

The experts at Alpine Tree and Lawn Care have the expertise and equipment to protect your trees and shrubs from all manner of pests. From deep-root fertilization to fungal sprays, our tree care program keeps your trees healthy and disease-free all season long. We also offer lawn service to keep your grass as green as your trees! If you’d like to learn more about what we can do for your unique situation, give us a call! Our experts are standing by to speak to you! You can reach us at (586) 884-7799¬†or leave us a message online. Want to know more about tree care topics? You can check out our monthly blog here or like us on Facebook!

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