Phytophthora infestans, also: late blight

Pathogen which causes potato late blight, the most serious fungal disease found in potatoes

Phytophthora infestans causes global harvest losses of around 20 percent.

The fungus initially attacks stems and leaves, causing grey-green blotches to appear, which later turn brown. It spreads via spores, which produce germ tubes to penetrate the plant tissue. Phytophthora is washed into the soil by rain, where it also infects the tubers. A single infected tuber is enough to destroy an entire crop.

Phytophthora wurde Mitte des letzten Jahrhunderts nach Europa eingeschleppt und erlangte traurige Berühmtheit als Verursacher der irischen Hungerkatastrophe von 1845, in deren Folge zwei Millionen Iren nach Amerika und Australien auswanderten.

Phytophthora was introduced to Europe in the mid-19th century and became notorious for causing the catastrophic Irish famine of 1845, which resulted in two million Irish people emigrating to America and Australia.

Phytophthora is still keeping plant breeders and researchers on their toes; it tenaciously evades all attempts to control it by constantly reinventing itself and forming new variants.

Genetic engineers are also working on control strategies for Phytophthora. A potato that contains two resistance genes from a Mexican wild potato has been undergoing deliberate release trials in several European countries since 2006.