- After invasion and colonization of the host, the pathogens come out of the host to maintain the continuity of the infection chain or disease cycle and escape death due to overcrowding.
- Once the pathogens exit from the host, they survive and are disseminated to other hosts and continue the infection cycle
Viruses can exist only with the living protoplasm and hence disseminated through their animate vectors like insects, fungi, nematodes, etc
The bacteria ooze out in the form of slime on the host surface from where they can be disseminated through water and insects.
Most plant pathogenic fungi grow out on the host surface and produce repeating spores (secondary inoculum), usually asexually, under favourable conditions.
The spores thus formed are disseminated through wind, water, soil, seed, vegetative propagating material, agricultural implements, etc.