The infection and perennation of the bitter rot fungus, Gloeosporium album, on apple leaves

In the period from late spring to leaf-fall (May-November) Gloeosporium album Osterw. was regularly isolated from leaves of the apple variety Cox's Orange Pippin affected by the disorder called ‘Cox-spot’. The fungus grew epiphytically on healthy apple leaves, producing a network of mycelium which developed sporulating pustules when in contact with damaged or moribund tissues. Both the imperfect and perfect stages of the fungus were found on overwintered leaves; isolates from ascospores and conidia proved pathogenic on wood and fruit.