Rhizopus Rot

The fungus produces enzymes that deteriorate the tissue holding the skin to the flesh of the fruit. Later, it turns dark gray to black as the fungus begins to develop sporangia, the fruiting structures that produce spores. Once released into the air, the spores can infect injured fruit in both orchards and on kitchen countertops. R. stolonifer is one species that commonly affects fruit in household kitchens. Uninjured fruit are not susceptible to the disease. However, fungal spores can remain dormant until the fruit is harvested. After the fruit ripens and is harvested, the fungus that is already present on the fruit skin is ready to germinate and grow as the fruit ages and the integrity of the skin deteriorates.