Needlecast refers to a variety of foliage diseases of coniferous species. These diseases are usually more severe on young trees and trees growing outside of their native range. Wet conditions favor the proliferation of needlecast fungi. By early to mid-summer, most of the infected needles have dropped or been “cast off”, leaving only the current season needles, though diseased needles remain attached for some time on spruce and larch. Although few trees die from needlecast, these are serious diseases because they are unsightly and can lead to other issues.
The management of needlecast requires commitment and patience given that nothing can be done for already-infected needles. However, there are products that have repeatedly been shown to be effective at preventing infection. These treatments are preventive only and solely protect those needles not yet infected. For example, for a spruce to recover from a severe infection, allow a fungicide program to protect the tree for at least three years before aesthetic evaluation of the tree. Your Bartlett Arborist Representative can also address cultural issues that will increase tree health and vigor.
