Tropic and Taxic Responses of Pathogens to Plants

Abstract

It is sometimes helpful to us as plant pathologists to attempt to understand the viewpoint of our adversaries. Imagine what it must be like to be blind, not to mention deaf and dumb, to be carried around by unpredictable forces and dumped at some foreign place, and then to have to find out if the surrounding territory happens to include a friendly host plant. This is a formidable predicament; but, as most of us can attest, plant pathogens are marvelous creatures. They have two primary senses, smell and touch, and are capable of using both effectively. Before analyzing our knowledge of these senses, we need to clarify some of the current terminology. Orientation responses by plant pathogens in host recognition can be divided into two groups: