Phytophthora infestans

• A highly infectious pathogenic organism that causes a serious disease of the potato, late blight or potato blight.
• The potato blight caused the Irish Potato Famine in 1845-49 which, it is estimated, caused over 1,000,000 people to starve to death and forced a further 2,000,000 to emigrate.
• For a long time Phytophthora infestans had been under control in North America because represented by only one mating type the pathogen was not able to quickly develop resistance to pesticides used against it. However in late 80's, the second mating type of the Phytophthora was first noticed in Wisconsin, and had probably already spread throughout of North America. The presence of the second mating type allows sexual reproduction and quicker gene recombination, which, in turn, leads to more rapid development of resistance to pesticides.
• The disease also affect other members of Solanaceae family such as tomato and eggplant.

Hosts of Phytophthora infestans

• Solanum tuberosum (potato, papas): life cycle, tuber anatomy at GeoChemBio 
• Solanum lycopersicum (Lycopersicon esculentum, Lycopersicon lycopersicum), tomato: life cycle, flower and fruit anatomy at GeoChemBio