A bacterial plant disease is the occurrence of plant diseases caused by bacterial microorganisms over large areas with significant impacts on crop and forest productivity or natural habitat (adapted from FAO, 2018).

Fungal plant disease is the occurrence of plant diseases caused by fungal agents over large areas with significant impact on crop productivity or natural habitats (Arneson, 2001; Moore et al., 2019).

Viral, mycoplasma and viroid plant disease epidemics are the occurrence of plant diseases caused by viruses, mycoplasma (syn. phytoplasma, mycoplasma-like organisms ) and viroids over large areas with significant impact on crop productivity or natural habitats (adapted from Nakashima and Murata, 1993; Hammond and Owens, 2006; FAO and IPPC, 2016; Rubio et al., 2020).