Fungicide applications may be required to suppress further infection on diseased trees. Proper timing is critical for disease control. A second application after 3 weeks is recommended. The diseased needles remain attached to the tree throughout the winter. The following spring, needles begin to turn purple and drop from the branch.
Most defoliation occurs late in the summer the second year after infection.
Because stomata are linearly arranged, the black dots, or fruiting structures of the fungus, characteristically line up in neat rows on the needles. Affected branches are eventually defoliated and killed by the fungus. It is the policy of Kansas State University Agricultural Experiement Station and Cooperative Extension Service that all persons shall have euqal opportunity and access to its educational programs, services, activities, and materials without regard to race, color, religion, national origin, sex, age, or disability. Kansas State University is an equal opportunity organization. These materials may be available in alternative formats.