What is the Orange Algae on Cedar Trees?
Cedar-apple rust is a fungal disease found on certain types of cedar, juniper and apple trees. Cedar-apple rust disease requires both an apple and cedar, or juniper tree, to complete its life cycle. Does this Spark an idea?
-
Types
-
Cedar-apple rust is an affliction of both apple trees and cedar trees, according to the Plant Disease Diagnostic Clinic at Cornell University. Juniper hosts include the Eastern red cedar, Southern red cedar, Rocky Mountain juniper, some prostrate junipers, and the Chinese juniper.
Features
-
Cedar-apple rust rarely does serious damage to cedar or juniper trees. The disease may not even be noticeable except in the spring, when the galls produce bright orange spore horns. If the disease is severe, however, small twigs can die or break off, which can result in severe defoliation.
-
Time Frame
-
Cedar-apple rust produces reddish-brown galls on the twigs of juniper and cedar trees that swell and produce long orange, gelatinous tendrils. In April, galls release fungal spores that only infect the rosaceous host, with the tendrils remaining on the galls through May. The galls last only one season, although the complete cycle takes two years. Spent galls dry and fall from the tree during the summer months. The cedar rust fungus overwinters in the galls.
Prevention/Solution
-
Apply fungicides to apple or flowering crab trees in the spring to prevent rust infection. Apply the first spray as soon as you notice the gelatinous tendrils on the cedar galls. Some states suggest the removal of juniper and cedar trees within a one-half to two-mile radius of apple orchards to disrupt the life cycle of the rust fungi. As vast areas of the United States are heavily populated with cedars and junipers, however, this would be an almost impossible task.
-
