Effect of Climate Change on Growth, Development and Pathogenicity of Phytopathogenic Telluric Fungi

© 2019, Springer Nature Switzerland AG. Soil microorganisms are extremely numerous and diverse. This diversity responds to the multitude of biogeochemical microenvironments of the soil as well as to the complexity of the forms of organic matter in the soil, their energy resource. Their distribution in the soil is very heterogeneous and is explained by the presence of conditions supporting the development of life. A very likely consequence of global warming would be a change in the range of some phytopathogens such as Phytophthora capsici, Rhizoctonia solani and Fusarium oxysporum. The fungi live in relatively homogeneous conditions. They are all heterotrophic microorganisms living under aerobic conditions. Indeed, certain microorganisms are known to have a distribution limited by temperature. To do this, we focused on the mean rate of mycelial growth as a function of the time (V max = d/t) of the three phytopathogens, at three different temperatures (20, 25 and 30 °C) and we also used a series of agroclimatic indices. The results show that F. oxysporum and R. solani have a very limited distribution at 22 and 30 °C (V max ¿ 10 mm) for 72 h; however P. capsici showed a V max ¿ 20 mm for 72 h, although the pathogen also depends on the temperature, probably its reproductive success as well as its distribution and speeds of development are extremely related to moisture. The pathogenicity analyzed by artificial inoculation of pepper seedlings shows that P. capsici is very aggressive at 30 °C, F. oxysporum showed virulence only at 25 °C but R. solani lost all virulence between 22 and 30 °C.