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 'Gros Michel' has been replaced by the current main banana on the market, the 'Cavendish', which in turn is (2015) at risk of total loss to a strain of the same fungus, 'Tropical Race 4'.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
Crop circle alleged 'cattle mutilation' sites." (in reference to cattle mutilation). A study by Eltjo Haselhoff reported that the pulvini of wheat in 95% of the crop circles investigated were elongated in a pattern falling off with distance from the centre and that seeds from the bent-over plants grew much more slowly under controlled conditions. Furthermore, traces of crop circle patterns are sometimes found in the crop the following year, "suggesting long-term damage to the crop field consistent with Levengood's observations of stunted seed growth." In 2000, Colin Andrews, who had researched crop circles for 17 years, stated that while he believed