They also cause plant diseases such as wheat rust, Dutch elm disease, and potato blight. The feeding stage of fungi is generally not visible to people since the hyphae are microscopic and are contained within the food, living or dead. Feeding stage hyphae are visible only if a huge mass is present. Generally, we notice fungi when a fruiting body is formed. This is the part of the fungus that produces reproductive cells called spores.
Spores are airborne so the fruiting body grows out of the food source to allow spore dispersal.
One type of fungus people frequently encounter is the black bread mold, Rhizopus . The feeding stage of the fungus grows in bread and other types of food. Each sporangium produces thousands of spores. Each spore, if it lands on suitable food, can produce feeding stage hyphae. For both of these examples, the portion of the fungus that is visible is the fruiting body.