The flesh of plums becomes brown with first lesion expression. The lesions are categorised as being firm, yet slightly soft, with an uneven margin. Spore masses of ash-grey / brown colour, cover the surface of infected fruit, as the fungus progresses. Botrytis cinerea is the causal pathogen.
The skin of the infected fruit readily slips away with a slight touch / sliding movement of one’s finger across the edge of the lesion. This phenomenon is referred to as ‘slip-skin’. The decayed tissue does not separate easily from healthy tissue. Spread of decay to adjacent fruit is common during storage.