The sporangiophores develop black sporangia, each containing thousands of spores, which give fruit a pincushion appearance. Rhizopus is an excellent saprophyte, able to live on decaying organic matter. It survives on crop debris in or on the soil between growing seasons. The fungus invades fruit through wounds and uses enzymes to break down and kill tissue ahead of the actual fungal growth. Disease development is favored by warm, humid conditions.
Rhizopus produces large numbers of spores that are easily spread by wind or insects.
Apply fungicides during the fruit-picking period. Handle fruit carefully during picking to prevent wounding. After harvest, cool the fruit to 46 o to 50 o F. Rapid postharvest cooling of fruit is essential for disease control. Sunscald may occur on nearly ripe fruit exposed to direct sunlight in hot weather. Damage usually occurs when hot, sunny weather follows periods of cool, cloudy weather.