Needle Cast Diseases of Conifers - Pine Needle Cast Disease

by John R. Hartman and Deborah B. Hill Needle infections by fungal pathogens can decrease the value of Christmas trees and landscape evergreens by causing needle discoloration and, more important, defoliation (Figure 1). Severe needle drop not only decreases tree value, but can result in poor tree health and vigor. Although most conifers are somewhat susceptible to needle diseases, certain varieties of Scots pines growing in locations favorable for disease may be severely affected. Needle diseases can be serious in shaded and crowded Kentucky landscapes as well as in Christmas tree plantations.
Scots Pine Needle Casts

Scots pines are widely grown as Christmas and landscape trees. Three important needle blight and needle cast diseases can affect Scots pines in Kentucky Christmas tree plantations. Although most Christmas tree plantings are relatively free of needle diseases, some serious outbreaks have been observed. Because there are differences in the timing of management activities for each disease, it is important for growers to identify the problem correctly. Look for needle blight diseases in shaded parts of the planting, on lower branches, and on the north side of individual trees.

University of Kentucky, College of Agriculture