Brown Spot Needle Blight

Brown Spot Needle Blight is a fungal disease caused by the Scirrhia acicula fungus. It affects loblolly pines, not humans. The fungus forms fruiting bodies under the surface of the needles, which burst through, leaving visible bands or spots on the needles.

Above-average rainfall during spring and summer creates the moisture and high humidity that allow the fungus to thrive. When conditions are moist, asexual spores are dispersed primarily by rain splash and, to a lesser extent, by wind. Overly dense timber stands make conditions even more favorable for the fungus to spread.

While outbreaks can appear dramatic, the damage may be relatively minor. Some dying trees in Arkansas have also been diagnosed with Needle Cast, which is caused by several different fungi. Treatments are available, so landowners should not assume the worst when they first observe symptoms.

Fungicidal treatments do exist, but they are often cost-prohibitive and generally unsuited to forest conditions. As a result, preventative management practices are usually the more practical approach for landowners with timber stands.

The most effective preventative measure is thinning timber stands before they become overly dense. Thinning increases airflow and promotes foliage drying, which reduces the conditions that allow the fungus to spread. If some trees are already infected, removing the damaged trees and the most susceptible species through thinning can also help.

If you are concerned about Brown Spot Needle Blight or other threats to your timber stand, you should reach out to your local AFM consulting forester. They can assess the situation and recommend appropriate management steps.