All about Pine Tree Diseases and How to Treat them

Common Pine Tree Diseases and their Treatment

First, it is important to know how to identify the fungal infections that can affect pine trees. It is essential to prevent the infectious disease from spreading to the healthy trees surround it. Fungal infection can easily spread through air, soil, rain and even contaminated pruning tools. 

If you notice signs of fungal infection on a pine tree, you should know how to treat it. Here are the commonly seen pine tree diseases and how to treat them:

1. Annosus Root Rot

Annosus root rot causes stunted needle growth and decay, called “butt rot”. This is a fungal infection and is usually seen in pine plantations where thinning has happened. The freshly cut stumps after thinning help the spread of this disease. Though this disease can effectively kill the infected tree, there is a simple solution to treat it before it gets out of hand and infects nearby healthy trees.

Annosus root rot usually affects the following types of pine trees:

• Loblolly 
• White pines
• Slash pines
• Longleaf
• Shortleaf 
• Lodgepole 
• Western White
• Ponderosa 
• Pond
• Jack
• Red
• Pitch 
• Whitebark 
• Virginia 
• Sand 

The most noticeable symptom of annosus root rot is substantial decay on the stump. You will notice the roots and butt developing stringy, soft white rot. The fungus makes fruiting bodies (conks) at the base of the tree trunk. These conks can vary in shape and are usually dark-brown to grey-brown in color on the surface while white on the inside. 

Annosus root rot is caused by the fungus Heterobasidion annosum and spread the most when the tree stump is freshly cut. Splashing rain or wind can carry the fungus spores from one infected tree stump to a healthy tree in close vicinity, with a cut surface. Once the spores land, they penetrate through the wood and cause an infection. This infection can remain dormant for decades before resuming its growth in the pine tree. 

The treatment for annosus root rot involves applying borax powder to the surface of the freshly cut tree stump to prevent the spread of infection to nearby trees.

Check out our blog on Ways to Remove a Tree Stump for more information.  

2. Brown Spot Needle Blight

Brown spot needle blight is usually seen infecting longleaf pine seedlings and Afghan pines that are grown in Christmas tree nurseries. You may see the signs of infection months after its onset but it can spread quickly in favorable weather conditions. 

This disease also affects other species of pine trees, including:

• Longleaf
• Afghan 
• Japanese Black
• Mugo
• Eastern White 
• Virginia 
• Red 
• Scots 
• Austrian 

The symptoms of brown spot needle blight are formation of circular gray-green spots on the pine needles in the fall. These spots tend to grow and can form rows that encircle the needles. This disease causes the infected needles to die and fall of prematurely. You can usually notice the symptoms of brown spot needle blight in the early fall, while the fungal infection usually spread during the warm, wet summer months. 

The cause of brown spot needle blight is the Mycospharella dearnessii fungus. It usually spreads in wet weather. Splashing rainwater carries its spores from an infected tree to a healthy one. This infection can quickly spread and affect large areas of the pine tree. It can also spread through contaminated pruning tools. 

The treatment method for brown spot needle blight involves using the managed fire burning technique every 2 to 3 years. This can help to remedy the infection and destroy the infectious fungal spores. You can even spray industrial-grade fungicide to remove this infection from pine trees. Gardening experts, such as Eden, advise homeowners to use fungicide between May and June, when the new needles are about half-grown, and apply it once again at least 3 weeks later. 

3. Cotton Root Rot

Cotton root rot is also known as Texas root rot and Ozonium root rot. It is a fungal infection that affects over 2,000 different plants and is one of the toughest fungal diseases to control. One can see cotton root rot mostly affecting trees in the Southwestern United States. This fungal disease mostly affects pine tree species that are exposed to high temperatures and growing in alkaline soils, such as Afghan pine. 

The signs of cotton root rot are slight yellowing/bronzing of the infected tree’s leaves. Three days later, you will notice the leaves wilting and dying completely. You can identify the fungal-infected areas by the circular patterns of dead plants which usually get enlarged over time. 

Cotton root rot is caused by the Phymatotrichum omnivorum which invades new areas through the soil. This fungus is able to survive in the soil for several years and can lay dormant at 8 feet deep in the soil. 

The treatment for cotton root rot involves:

• Forming a ridge of soil around the tree’s drip line with a 2-inch thick layer of organic matter or cow manure 
• Scatter ammonium sulfate and sulfur over the manure
• Flood the bowl of soil with water to let the water seep to a depth of 3 feet
• Keep the soil moist for several weeks

With this treatment method, the infected pine tree will likely recover within the same season. 

You can also treat cotton root rot by planning resistant grass crop around the infected area. This kind of crop creates an effective barrier that prevents the spread of the fungal infection. 

Conclusion

The most common pine tree diseases include annosus root rot, brown spot needle blight and cotton root rot. If you are unable to treat the infections using the treatment methods listed above, feel free to consult and hire professional lawn care services, such as Eden, for best result.