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,
Agriculture in Panama made land titling more necessary. Moreover, insecure tenure has been a particularly severe constraint to improved techniques and to commercial crop production. The cost of titling a piece of land has been too high for most subsistence farmers. Between 1969 and 1977, the government attempted to redistribute land. In the late 1980s the distribution of land and farm incomes remained very unequal. In 1980, 58.9 percent of farms had an annual income below US$200. The issue of unequal land distribution has not been as explosive in Panama as in many other Latin American countries. This was because of the service-oriented