Answer:
Phytophtora infestans is host-specific pathogen and can reproduce both asexually and sexually.
Step-by-step explanation:
Asexually: The spores (sporangia) of P. infestans are transported via wind or water. Once they land on the plant tissue, the zoospores are released. When conditions are warmer, zoospores are germinated. Here, a germ tube is formed which penetrates into the plant tissue and allows the newborn to get nutrients from plant sap for its own growth and development.
Sexually: Sexual reproduction takes place when both male and female are present. Here, antheridium and oogonium nuclei (haploid) fuse together to form a diploid oospore. The oospore then develops into sporangium and the rest of the cycle follows the same pattern as of asexual reproduction.