This disease was first noted on the quince in New Jersey in 1892. It was subsequently observed in New Hampshire in 1910 and in Connecticut in 1911. It is now common in New England and in the Middle Atlantic region. The Orange quince seems particularly susceptible. The disease also affects the apple and Chinese quince.
Fruit Spot, or blotch, appears late in August or early in September. Lesions show anywhere on the surface of the fruit, but are most numerous near the blossom-end. Here they frequently unite, forming one continuous blotch. The spots are one-fifth of an inch or less in diameter, their surface is slightly sunken, and the affected tissue firm. At first the diseased portion is a deeper green than the surrounding tissue. Later the lesions are black. In the center of each spot black specks - fruiting bodies of the pathogene - appear in great numbers. See fuller discussion of this disease under Apple, page 87.
Brooks, Charles. Quince blotch and apple fruit spot. Phytopath. 3:
249 - 250. 1913. Halsted, B. D. Some fungous diseases of the quince fruit. The quince blotch. New Jersey Agr. Exp. Sta. Bul. 91: 13. 1892.