Diseases of Cryptomeria
- Cryptomeria japonica is an evergreen tree that grows in zones 5 to 8 in the United States.evergreen tree image by Seneka from Fotolia.com
Cryptomeria japonica or Japanese cedar is an evergreen tree native to Japan, but grows in zones 5 to 8 in the United States, according to North Carolina State University. The tree resembles the Leyland cypress with its tall pyramid like shape that can reach heights of up to 50 feet, and thick spreads of up to 20 feet, according to the North Carolina State University. Cryptomeria japonica exhibits hearty growth and is only susceptible to a few diseases. - Leaf blight of the Cryptomeria japonica, caused by a variety of fungal pathogens, leads to browning of the tree's needles. According to the U.S. Department of Agriculture, leaf blight of the Japanese cedar is superficial to the tree's needles, but rarely causes physical harm to the tree. Because a variety of fungal pathogens cause the disease, prevention is difficult. However, like most fungal pathogens, keeping the plant's needles and branches dry prevents the fungus from reproducing and infecting the tree. The U.S. Department of Agriculture recommends applying fungicidal sprays and keeping the foliage of the tree free of moisture to help prevent the disease.
- Leaf spot of the Japanese cedar is an uncommon disease caused by a variety of fungal and bacteria pathogens. Leaf spot can cause discoloration of tree needles, leaf or needle death, and red to brown spots on the foliage, according to the University of Connecticut. If untreated, the disease can cause branch dieback and death of foliage. According to the North Carolina State University College of Agriculture and Life Sciences, leaf spot on Japanese cedar is not very serious or common and if branch dieback occurs, cutting the diseased branch can control the problem. Fungicides and bactericides also can be applied to prevent infection.
- Phytophthora Root Rot, caused by the fungal pathogen Phytophthora cinnamomi, is a potentially devastating disease to the Japanese cedar. According to North Carolina State University, the root rot is most common in poorly drained soils and in growing locations that contain a lot of free water in the soil, such as flood plains, near streams and drainage sites. The fungus affects the roots of the plants below the soil surface, which makes diagnoses of the disease difficult. However, common symptoms include yellowing of the foliage, foliage wilt and root decay, according to North Carolina State University. To control the disease, plant in well-drained soil, use fungicide and disease free seedlings.
