Cherry leaf spot is a fungal disease of sweet, sour, and ornamental cherries. While this leaf disease is rarely a death sentence for trees, it can result in reduced blossoms, weakened trees, and increased risk for winter injury. This is especially likely for sour cherries.
Symptoms include small, purple-colored leaf spots approximately 1/8 to 1/4 inch in diameter. Over time, spots turn brown and may fall out of leaves, leaving “shot holes” in the centers of spots. Severely infected leaves turn yellow and may drop prematurely. Heavily infected trees becoming mostly defoliated by mid-summer.
Cherry leaf spot is caused by a fungus which survives winter in fallen leaf debris. In spring, spores are released and carried to new leaves by wind or splashing rain. Primary infection occurs in spring during periods of warm (60°F to 70°F), moist conditions. More infections may occur in favorable conditions through the growing season.
Sanitation is critical for management of cherry leaf spot. Rake and destroy all fallen leaves at the end of the season. Do not compost diseased plant material. Fungicides are not recommended for landscape or backyard trees. Commercial producers should consult the Commercial Fruit Pest Management Guide (ID-232) for fungicide recommendations. Read and follow all label instructions.
Selecting cherry trees that are resistant to leaf spot is the best way to avoid this disease.
For fruit, tart cherries are easier to grow and maintain. The tart cultivars Northstar and Meteor provide the most resistance to leaf spot. Information published in the American Society for Horticultural Science found five ornamental flowering cherry species with full resistance to Cherry Leaf Spot.
– Kwanzan Cherry (Prunus ‘Kanzan’) is a small tree with double pink blooms in the spring. It’s considered to be one of the showiest of the Japanese cherries.
– Japanese Apricot (Prunus mume ‘Versicolor’) is the ideal size for small gardens. Starting as early as January, it produces beautiful fragrant flowers over many weeks.
– Gray’s Bird Cherry (Prunus grayana) – has intense yellow-gold fall color and fruits to attract birds.
– Takesimensis Cherry (Prunus takesimensis) is somewhat new to the horticulture trade. Introduced by the US Arboretum, it tolerates wet sites and tough sites.
– Fuji Cherry ‘February Pink’ (Prunus incisa) is a small tree with early pale pink flowers.
Any of the cultivars above would be a good replacement for commonly planted Sargent and Yoshino Cherry as they are both susceptible to cherry leaf spot.
For more information, contact the Christian County Cooperative Extension Service, 270-886-6328.
