I. The Importance of Powdery Mildews. . . . . . . . 51 II. Life Cycle of Powdery Mildews . . . . . . . . . . . . . 53 A. Asexual Reproduction. . . . . . . . . . . . . . . . . . 53 B. Sexual Reproduction . . . . . . . . . . . . . . . . . . . 53 III. Interactions with the Host Plant . . . . . . . . . . . . 55 A. Influence on Host Metabolism. . . . . . . . . . . 56 B. Induced Susceptibility and Re...

The existence of genetic variation for resistance in host populations is assumed to be essential to the spread of an emerging virus. Models predict that the rate of spread slows down with the increasing frequency and higher diversity of resistance alleles in the host population. We have been using the experimental pathosystem Arabidopsis thaliana-tobacco etch potyvirus (TEV) to explore the inte...