ABSTRACT
Microbial plant pathogens – oomycetes, fungi, bacteria, phytoplasmas, viruses and viroids – infect crops, weeds and wild plants in all agroecosystems. Microbial plant pathogens induce various types of symptoms, the severity of which may depend on the levels of susceptibility/resistance of the cultivar, virulence of the pathogen species/strains/varieties/isolates, and prevailing environmental conditions. Microbial plant pathogens may be disseminated predominantly via seeds/propagules, soil, irrigation water and wind. Soilborne microbial plant pathogens commonly cause damping-off, stem rot, crown rot and root rot in planta and soft rot in tubers and other storage organs. Sheath blight, foliar or flower blight symptoms may be induced, when infected by the spores released from infected plant debris left in the soil after harvest. Transmission of some soilborne pathogens may also occur through seeds/propagules finding their way rapidly even to distant locations.
