What is Dothistroma Needle Blight?
Dothistroma Needle Blight causes needle spots, discoloration, and substantial needle loss in heavily infected areas. Austrian Pines are particularly susceptible, though the disease also attacks Mugo, Ponderosa, and perhaps other species of Pine.
What are the symptoms of Dothistroma Needle Blight?
The first symptom is scattered spots, varying in color from yellow to red. These appear in midsummer or fall, and later may turn brown. The tip of the needle beyond the spot then turns brown and dies, while the base remains green for a while.
How do you control Dothistroma Needle Blight?
Cultural treatment: When isolated cases of the disease are found, raking and removing fallen infected needles may help control the disease. Typically, however, this practice is impractical and relatively ineffective.
Chemical treatment: Some copper-containing fungicides registered for control of the disease are effective. Also, root feeding will help to increase health and fight the disease.