Pest
Management Home Page
Agriculture, Natural
Resources, & Community Development Home Page
Dr. John F. Baniecki Black spot, one of the two most destructive diseases of roses in the East, is recognized by the nearly circular black spots that appear on the leaves. These are distinguished from other leaf spots by their uniform black color and generally fringed margins. Lesions range from 1/16- to 1/2-inch in diameter but may coalesce to form large, irregular blotches on leaflets. The entire leaflet may become yellow or chlorosis may occur around individual spots. The premature defoliation that follows severe infection of the causal fungus, Diplocarpon rosae, makes this a destructive disease. Defoliation reduces the plants vigor and predisposes the plant to other diseases, insects, winter, and drought injury. |
