Disease and Pest Issues

Click on an image to view larger

What is wrong with this Spruce?

The needles on the south side only are turning reddish-brown. It is planted right near the alley. No insects found. No diseases found. It is getting plenty of water. Further investigation revealed that alley construction of a new sewer line caused it. Large backhoes spewed hot exhaust on all trees at the same height up and down the alley, killing whole sections of all trees.

What is wrong with this Aspen?

Many leaves are turning black and others have small brown spots. Tom Yelvington on the right is examining them to determine the cause. Turns out it is Marssoninia leaf spot disease. Leaves develop brown spots that later turn black. There are many other diseases that get on tree leaves.

Why are these Cottonwoods dying?

They get plenty of water, yet the leaves are dying and falling off the trees in July. There are no insects or diseases found. Since they are dying on the road side first, it prompted Tom Yelvington to ask if any herbicides were used on the gravel to keep weeds from growing. The answer was yes, a product purchased at a farm store for killing weeds was used on the gravel parking area. The tree roots picked it up and eventually killed these large trees.

What is wrong with this tree?

The bark is missing on one side. A lawn mower, weed trimmer, or something else scraped the bark off years ago. When this happens, the roots also die directly below this spot with no bark. If the tree doesn't grow over this area, it will continue to suffer and decline. It is already at risk to fall over, and the more it decays, the higher the chances of it falling over.

What is with with this tree?

It started with a trunk injury that hampered the flow of nutrients and water in both directions, up and down. Eventually a large limb died due to reduced uptake, and it was cut off near the top of the photo. Since it didn't begin growing over this large area, (compartmentalization) it began decaying internally from the cut downward. The holes are from borers that invaded the area and infested the dead parts of the trunk.

Why did this tree fall over in the wind?

Because of the trunk decay like in the other two photos. It was damaged first by a lawn mower or something that scraped the bark off one side. Then decay set in, weakening the trunk.

Why is the top of this Spruce dying?

Because White Pine Weevils began boring into the top of the tree and drilled downward. This took only one year to infest the tree this much. Is it savable? Yes. The dead part was cut off, the insects killed with Permethrin, and the tree was fertilized. The tree grew a new top and it is doing fine today.

What is wrong with this Apple tree?

A new infection of Fireblight bacteria is killing the end of the limb, wilting the leaves. Most likely a bee pollinated a diseased tree, then went to this tree and spread the bacteria. Can it be "saved"? Yes. Cut off the diseased parts when the tree is dormant, in the winter. Disinfect tools between cuts to avoid spreading it more. Treat in the spring and fall with Reliant and Pentrabark, or call us to do it for you. It can be found at Amazon as a bundle. Do it every spring and fall for the life of the tree since it is such a continual problem in Montana.

A good thing to know is that in order for diseases like this to affect your trees, there has to be three elements in play. It is called the disease triangle. If any one of these things is missing, your trees cannot contract a disease. Using Fireblight as an example, it is the pathogen. The host is any other fruit tree. The favorable environment is wet, cool, and humid. When all three of these things exist, your fruit tree can get this disease.