Common Pine Tree Diseases

The name gives it away, but Needlecast and Needle Blight are fungi that affect the pine needles on a pine tree. The fungi turn the needles brown, and they will start to drop prematurely. Certain conditions, such as a pine tree not being planted correctly or something like drought, can cause this fungus to sprout. These diseases affect most of the different types of pine trees (spruce trees too, with their needles).

Some symptoms you might see with Needlecast and Needle Blight include:

• Brown coloring and needle drop prematurely
• A canopy that’s quickly thinning
• Tiny black bumps or dots (may require a magnifying glass to see)
• Branch dieback, where if a branch loses most of its needles in a 3-4 year time span, the branch will eventually die

As a clarification, while Needlecast and Needle Blight feature a lot of the same symptoms, they both target trees differently. Needlecast primarily targets older needles, while Needle Blight targets younger growth.

Pine wilt is a highly lethal disease of pine trees caused by a nematode (a type of roundworm). This nematode will damage a pine tree based on conditions relating to moisture and temperature. These nematodes spread by being transported on the backs of pine sawyer beetles. When the tree is fed on, the systems involved with water conduction start to fail, and this causes wilting (losing rigidity and starting to droop toward the ground) in dry conditions.

This tree disease shows up more during spring and blooms in the summer, and when it does, you’ll notice symptoms like brown coloring in the needles; the needles might stay on the tree for several months without dropping; and finally, there will be a loss of resin in the inner part of the tree’s bark and branches due to losing water.

There are many different forms of root rot that affect plants and trees, and Annosus root rot is a particularly destructive form of it for pine trees. This fungus grows down in the stump roots of a tree (with stumps that are freshly cut). This disease eats away at the very structure of what keeps a pine tree stable and upright. One of its trademark features is the white and brown mushrooms that form at the base of the tree. This can spread across multiple trees if close together.

The first signs of Annosus root rot will start with the needles on the pine trees turning light green or yellow in color. Needles that are older will drop prematurely (as you see in the photo on the right), and any remaining needles are going to clump up in tufts at the tips of shoot branches. That means that needles will grow together in bunches at the tips of the branch. You might also notice the wood on the tree is soaked in resin too.

If you have any younger pine trees planted around you, be on the lookout for Fusiform rust. This tree disease is caused by a fungus that produces spindle-shaped galls on the branches and stems. In effect, this weakens the trees and can lead to their death. Now, this is a disease that reportedly is not found as much here in the northeastern part of the United States, but it’s still important to remain cautious just in case it is spotted in a rare instance. Weather conditions and the environment are constantly changing these days, and anything can happen. This disease does rely on oak trees as a way for the disease to spread, and Buffalo and Western New York have plenty of oak trees. 

When identifying the symptoms of fusiform rust, as noted already, you will spot lesions growing on the tree that will eventually turn into spindle-shaped galls. These galls can be noted on both the stems and branches, and the more they develop over time, the more they might produce resin and form cracks in the branches. When spring season comes around, as you will see in the photo on the right, the trees will create these orangish and sometimes yellowish-looking spores. This part of the disease will form around 2 years after the galls appear.