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 (implement) Crop (implement) A crop, sometimes called a riding crop or hunting crop, is a short type of whip without a lash, used in horse riding, part of the family of tools known as horse whips. A modern crop usually consists of a long shaft of fiberglass or cane which is covered in leather, fabric, or similar material. The rod of a crop thickens at one end to form a handle, and terminates in a thin, flexible tress such as wound cord or a leather tongue, known as a keeper. The thin end is intended to make contact with the horse,