Influence of some external conditions upon infection of hosts with powdery mildews

Abstract

It has long been observed that one condition or another of the environment is favorable to the perpetuation and spread of fungous diseases. For example, it is very easy to recognize the close relation which exists between the humidity of the atmosphere and certain fungous diseases. Indeed, the relation of the host and the parasite or the dependency, directly or indirectly upon external conditions, of the one to resist the attacks of the parasite, and of the other to invade the hosts tissue, and to firmly establish itself, offers a field of valuable research.