• Transport of spores or infectious bodies, acting as inoculum, from one host to another host at various distances resulting in the spread of the disease, is called dispersal, dissemination or transmission of plant pathogens.
• In fungi, productions of asexual and sexual spores follow the active vegetative growth of the fungus in or on the host tissues and are dispersed mechanically in time and space by various means.
• In bacterial diseases, the bacterial cells come out on the host surface as ooze or the tissues may be disintegrated so that the bacterial mass is exposed and then dispersed by various physical and biological agencies.

• Viral diseases which have no such organs are transmitted by insects, mites, phanerogamic parasites, nematodes and human beings.

The dispersal of infectious plant pathogens in space occurs through two ways:

1. Autonomous or direct or active dispersal.

2. Indirect or passive dispersal.