Cankers on Rose
Coniothyrium, Phomopsis, Botryosphaeria, Botrytis and others
4 (1 = rare 5 = annual)
5 (1 = very little damage 5 = plants killed)
spp. (rose) and other plants.
Cankers can cause dead areas on the stem that can enlarge and eventually kill the stem or even the entire plant. However, depending on host and pathogen the symptoms can vary.
The pathogen overwinters on dead plant material. Spores are wind blown. During wet weather, spores infect stressed plants.
Keep plants healthy - water, and fertilize to improve vigor. Practice good sanitation - prune out/remove infected tissue when plant is dry but before spring growth starts. Prune cankered canes immediately above the second healthy node below the diseased areas, or to the next branch down, or to the main stem if needed. There are no effective fungicides for most canker fungi.