Environmental Physicochemical Factors Affecting Establishment and Course of Disease

Abstract

A discussion of the conditions leading to inception and establishment of diseases through transmitted seed falls naturally into the following two items:

• (1) The external factors of the environment exerting an influence on the host, on the pathogen, and on the association of host and pathogen.

• (2) The internal factors, i.e. the gene-controlled pathogenicity of the parasite, and the gene-controlled susceptibility of the host.