Apple scab

petioles and fruits and sometimes on twigs and bud scales. The lesions are olive-green. When spores are produced, the lesions become grey and fluffy. The [...] The ascospores are wind-dispersed to the fruit trees and will germinate if free water is available. They infect the plant by direct penetration of the cuticula [...] fallen off the trees. In response to the infection, the plants produce cork as a defence against further growth of the fungus. In cultivars that are more resistant