DENSITY-DEPENDENT GROWTH AND LIFE-HISTORY EVOLUTION OF POLYCYCLIC LEAF PATHOGENS - A CONTINUOUS-TIME GROWTH-MODEL

A density-dependent growth model of a polycyclic leaf pathogen is anal ysed. Viability and fecundity of the pathogen are regulated by the cur rent population density. Spores are produced continuously from a sporu lating infection until death of the infection, and consequently, all a ge classes of infections are present at a certain point in time. The l eaf area of the host varies with time. Evolution of life history strat egies are studied by letting different pathogen genotypes compete with each other. Evolution of life history strategies and evolution of imp act of disease are discussed in relation to the ecology of the host-pa thogen system. The model is exemplified by Erysiphe graminis f. sp. ho rdei growing on Hordeum vulgare.