The picture shows a bowl of apples, one heavily infected with brown rot. The infection began at the site of a puncture wound (centre) that occurred when the apple - windfall - fell from the tree. Brown rot in apples is most commonly caused by the Ascomycete Monolinia fructigena (syn. Sclerotinia fructigena ). The fungal hyphae grow into the fruit tissue from the site of infection, eventually producing, as here, concentric rings of light brown felty pustules bearing conidia (asexual spores). Affected fruits that are left on the ground may mummify over the winter and produce further spores in the following Spring, resulting in further infections. The fungus is easily spread; within 24hrs of this picture the healthy apples touching the rotting one had surface infections at their point of contact