Glomerella cingulata causes anthracnose symptoms on a wide range of woody and herbaceous ornamentals and may also attack senescent or injured tissue as a secondary invader. G. cingulata is a cosmopolitan pathogen that can be introduced into a greenhouse on numerous flower and foliage crops. The disease could also originate from infected landscape or native plants and be introduced into the greenhouse through open vents on wind-driven rain or insects. The fungus is spread by splashing water and wet leaf surfaces encourage infection. Avoid overhead irrigation if possible, water in the morning to allow plant surfaces to dry quickly, and maintain good air circulation. Scout greenhouse for symptoms, especially when plants are small and closely spaced. Remove infected plants and discard. Drench adjacent plants with a fungicide. Champ, Champion, Kocide, KOP-Hydroxide, Bayleton, Cygnus, Eagle, Fosphite, Heritage, Systhane, and Manzate 80 WP are registered for ornamentals. Start with healthy transplants in a well drained soil, provide balanced nutrition, and avoid over-watering. Grow plants on raised benches to prevent contamination from native soil and start with sanitized pots, flats, and benches.
Fact Sheet: Leaf Spot Diseases on Ornamental Crops