Crop diversity fruit trees and banana plants) are cloned. A single pest or disease could threaten a whole crop due to this uniformity ("genetic erosion"). A well-known historic case was the Irish Potato Famine of 1845-1847, where a vital crop with low diversity was destroyed by a single fungus. Another example is when a disease caused by a fungus affected the monocultured 1970 US corn crop, causing a loss of over one billion dollars in production. A danger to agriculture is wheat rust, a pathogenic fungus causing reddish patches, coloured by its spores. A virulent form of the wheat disease, stem rust,
Crop Crop A crop is a plant or animal product that can be grown and harvested extensively for profit or subsistence. Crop may refer either to the harvested parts or to the harvest in a more refined state. Most crops are cultivated in agriculture or aquaculture. A crop is usually expanded to include macroscopic fungus (e.g. mushrooms), or alga (algaculture). Most crops are harvested as food for humans or fodder for livestock. Some crops are gathered from the wild (including intensive gathering, e.g. ginseng). Important non-food crops include horticulture, floriculture and industrial crops. Horticulture crops include plants used for other crops