It was identified as Asperisporium caricae, Black spot disease. There should be numerous small black angular spots. Growth on media is limited, but the spores are easily recognisable. If the disease is heavy on the leaves it is likely to be the same on the fruit. Make slide preparations by scraping the surface of some of the spots on both leaves and fruit. For Asperisporium, look for small dark two-celled spores and short dark conidiophores in tight clusters (check in Ellis Dematiaceous Hyphomycetes p.273). For Corynespora, look for large light brown tapering spores with transverse septa on long condidiophores that are scattered singly over the surface of the spot (they are very pretty spores. See p.373 in Ellis).

The variety Sunrise is particularly susceptible to the disease.