The Q&A Archives: Orange mold on evergreens

Question: each spring i get an infestation of an orange mold, or fungus in m low lying evergreens-have tried fungus spray, to no avail- what are your suggestions?

Answer: I would be inclined to collect some of the fungi and take it to your local cooperative extension office for positive identification. You didn't mention what evergreens you are growing but the orange color and the fact that you find it every spring makes me suspect it might be Cedar Apple Rust. Cedar-apple rust and related rusts are caused by species of Gymnosporangium that attack evergreen trees and shrubs in the juniper family. These include eastern red cedar (Juniperus virginiana), Rocky Mountain juniper (J. scopulorum), creeping juniper (J. horizontalis), common juniper (J. communis), and certain exotic junipers planted as ornamentals. Red-brown galls of cedar-apple rust form on eastern red cedar over a period of nearly two years. The mature galls (`cedar apples') produce orange gelatinous tendrils during moist spring weather. Heavily infected trees can be quite striking. The spores formed on these tendrils infect apple leaves and fruits. The galls are perennial and may live for several years, producing new crops of spores each spring. Like many other rust fungi, cedar-apple rust and other Gymnosporangium rusts alternate parasitism between two kinds of plants?one being the evergreens, the other or alternate hosts are trees in the pome fruit group of the rose family, including apple, pear, quince, hawthorn, mountain ash, and juneberry. For positive diagnosis and current control measures, contact your local cooperative extension office.

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