Systems

Abstract

A pathosystem is comparable to an ecosystem. Indeed, a pathosystem is a subsystem of an ecosystem and is defined on the basis of parasitism. In particular, the term pathosystem emphasises that the whole subject of crop loss due to parasites is one system, and not several, entirely distinct systems as implied by the disciplines of plant breeding, plant pathology, entomology, nematology, and so on. These disciplines have tended to be separate, water tight compartments for far too long. Very broadly, breeders have studied the host and parasitologists have studied the parasites, and the areas of common ground have been remarkably limited. It will become apparent that the pathosystem concept, consisting of pathosystem analysis and pathosystem management, unites these disciplines into one cohesive new approach. The very existence of the word ecosystem has accelerated systems analysis in ecology (Watt, 1966; Patten, 1971, 1972); it is possible that the word pathosystem will do the same for the prevention of crop loss. However, before considering plant pathosystems, it will be useful to consider some of the wider aspects of the systems concept and its effects on science in general.