For a disease or pest to cause yield losses, the host and pathogen or pest must coincide within a favourable environment. With changing weather patterns and cropping systems, abiotic and biotic components influencing potential epidemics are modified and new interactions occur. Since they affect plant phenology and the survival and multiplication rates of microorganisms and insects, temperature and humidity are key factors of epidemics. The incidence of pathogens and pests has noticeably evolved in recent years; globalization, in particular, has increased threats from new transboundary pests and diseases. Factors driving new outbreaks include extraordinary climatic events and trends in temperature selecting pathogens and their natural enemies towards new critical thresholds for inoculum survival. Disease cycle components such as survival, infection, colonization processes and latency period, in addition to production and dispersal of inoculum, are all affected. Climate is most likely a strong driver of evolutionary change in plant and pathogen populations by interfering with host-pathogen interactions, gene expression and population dynamics. Disease monitoring and identifying the parameters affecting pest outbreaks improve epidemic risk assessment and knowledge of the enemy. Strategies to prevent the negative effects of pests and diseases include stringent quarantine regulations, adopting cropping systems that favour biocontrol or avoidance and, most importantly, resistance breeding, cultural practices and sound phytosanitary measures. This review highlights recent changes in microbial communities and the evolution of selected pathosystems encompassing small grains, tubers and agroforestry. The value and effectiveness of integrated crop management and sustainable approaches for controlling potential new disease and pest epidemics, in the context of climate change, are emphasized.

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