ENVIRONMENT AND PLANT HEALTH: A NEMATOLOGICAL PERCEPTION

The direction and aims of research are greatly influenced by the impact of bold ideas that elicit new perceptions of familiar topics. For example, Flor's gene-for-gene hypothesis (26a), the debate on horizontal and vertical resis­ tance initiated by van der Plank (77) and, in nematology, Seinhorst's (58) mathematical models all have stimulated and affected the direction of re­ search. Furthermore, they have inevitably led to the questioning of basic assumptions and to some controversy. Plant nematology has some areas (perhaps too few) where opinions differ: one that deserves consideration is environment, not only because of its fundamental role in plant health but because perceptions of its nature and significance vary. This essay examines some key environmental aspects of nematology that relate to plant health.