Crop diversity are all susceptible to a single fungus, "Fusarium oxysporum" (Panama disease); large areas of the crop were destroyed by the fungus in the 1950s. 'Gros Michel' has been replaced by the current main banana on the market, the 'Cavendish', which in turn is (2015) at risk of total loss to a strain of the same fungus, 'Tropical Race 4'. Such threats can be countered by strategies such as planting multi-line cultivars and cultivar mixes, in the hope that some of the cultivars will be resistant to any individual outbreak of disease. The implications of crop diversity are at both local
Brown blotch disease blotch disease causes large economic losses due to a perceived decrease in quality, even though it does not cause any health problems in humans. Brown blotch disease is observed in mushroom farms all over the world. In the UK, the Netherlands and France, 15% of the crop weight is affected by brown blotch disease, while in Italy it is even worse; in the worst years, 40% of the total weight of mushroom crops is affected by brown blotch disease in Italy. Because brown blotch disease affects all mushroom species, exotic mushrooms grown in eastern countries such as Japan, China, and