Conifers Disorder: Rhizosphaera Needle Cast
What is Rhizosphaera Needle Cast?
Rhizosphaera needle cast occurs throughout Wisconsin but infects only certain conifer species. Colorado blue spruce is the most common host in Wisconsin.
What are the symptoms and effects of Rhizosphaera Needle Cast?
Rhizosphaera needle cast starts from the bottom of the host tree and progresses upward. Second-year needles on the lowest branches are infected first. These needles take on a yellow mottled appearance, then turn brown and drop from the stem.
How do you control Rhizosphaera Needle Cast?
Cultural treatment: Do not allow spruce trees to undergo drought stress. Water when necessary. Fertilizing will also help keep your spruce healthy as well as fight off the fungus.
Chemical treatment: Two chemical treatments will help control Rhizosphaera needle cast: fungicides that contain copper, and chlorothalonil.