ABSTRACT

Potato is afflicted with a number of fungal pathogens; however, major losses are generated by a limited number of these pathogens. Of greatest importance has been Phytophthora infestans (Mont.) de Bary, causal agent of late blight. The ability of P. infestans to develop new races has been countered by introgression of numerous resistance genes from wild germplasm. Sexual recombination and asexual genome plasticity allow P. infestans to overcome current varietal resistance and to develop greater virulence. Among potato pathogens, P. infestans is unique in its global prevalence and high level of crop loss.