ABSTRACT
The unique combination of biological factors and human intervention in the life histories of wind-dispersed plant pathogens can result in such exceptional events as invasions of new territory on global or continental scales or the rapid spread of virulent genotypes on previously resistant cultivars. The dispersal of the pathogen or disease is important not only for spread of plant diseases but also for continuity of the life cycle and evolution of the pathogen. The dispersal of infectious plant pathogens in space occurs through two ways: autonomous or direct or active dispersal and indirect or passive dispersal. Spore dispersal in space for many mushroom and toadstool species is influenced by the effects of gravity. To understand how adaptation of pathogens to their hosts and environments is translated in terms of aggressiveness, it is essential to be able to link the concept of aggressiveness to other concepts used in evolutionary epidemiology, that is, fitness and virulence.
