Late Blight
🦠 Diseases●● Intermediate
Late blight (Phytophthora infestans) is the disease that caused the Irish Potato Famine. It thrives in cool, wet conditions (60–70°F with high humidity) and can destroy an entire planting within a week. Lesions appear water-soaked, turning brown with white fuzzy sporulation on leaf undersides. Unlike true fungi, the Phytophthora oomycete spreads via airborne sporangia that can travel miles on wind.