![]() Do not plant apple or crabapple trees near Eastern red cedars. Prune out all galls on the juniper, if possible. Prevention & Treatment: Select resistant varieties of apple (such as ‘Enterprise’, ‘Pristine’, ‘Liberty’ or ‘Redfree’) or juniper. In the late summer, these yellow spots form spores that are spread to the leaves and twigs of nearby junipers (within 2 miles) to infect them. Symptoms that occur on the apple trees appear as yellow spots on the upper leaf surface. In the spring following a rain, the galls produce large, orange, gelatin-like tendrils, full of spores, which can blow a half-mile to infect nearby apple and crabapple trees. On juniper, hard, brown, up to 2-inch diameter galls form near the ends of the branches in the summer. Joey Williamson, ©2021 HGIC, Clemson Extension These spores are then wind disseminated to nearby junipers. During summer the fungus produces spore bearing spots on the lower apple leaf surfaces. Damaged or stressed tissues are more susceptible to Kabatina twig blight.Ĭedar apple rust spots form first on the upper surface of apple leaves. The symptoms are the same as described for Phomopsis tip blight, except this fungus kills older (usually 1-year-old) twigs in the spring. Kabatina Twig Blight: This disease is caused by the fungus Kabatina juniperi. Apply all chemicals according to directions on the label. Select a fungicide labeled for use on junipers containing one of the following: mancozeb, thiophanate-methyl, or copper fungicides. If chemical control is necessary, fungicides are available to provide protection, but they must be applied before infection occurs. Except on highly susceptible cultivars, pruning will usually control these diseases. Promptly prune and remove any diseased or browning branches as they occur. Do not crowd plants, and avoid using sprinkler irrigation. Plant junipers in areas with good air circulation to promote rapid drying of the needles. Do not stress junipers by planting them in shaded or poorly drained locations. Purchase disease-resistant varieties that are healthy with no evidence of dead or dying twigs. First, closely inspect the entire plant, since symptoms of tip blight and twig blight can be caused by other problems, such as drought, overwatering, or root injury. Prevention & Treatment: Each of these diseases requires similar methods of control. This disease is sometimes confused with mite damage. Needles of spur branches turn brown and die usually in the late summer, leaving a plant with an inner crown devoid of foliage. Branch tips usually remain healthy and green. As disease development progresses, the needle browning spreads upward and outward. It begins by infecting the oldest needles that are located on the lower branches, inside of the plant. Watch for disease development during the spring or summer flush of new growth when warm, wet conditions are present.Ĭercospora Twig Blight: This disease is caused by the fungus Cercospora sequoiae var. Scraping away the bark will reveal a sharp line between discolored, dead wood and healthy wood. Infected twigs first become pale, then turn reddish-brown and finally become brown after death. The new, immature growth becomes infected while the darker green, mature foliage remains resistant to infection. Phomopsis Tip Blight: This disease is caused by the fungus Phomopsis juniperovora and begins by infecting the tips of branches smaller than the diameter of a pencil. Phomopsis blight ( Phomopsis juniperovora) on juniper.īruce Watt, University of Maine, ![]()
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