A tomato plant, Solanum lycopersicum (formerly Lycopersicon esculentum ) infected by the Oomycete Phytophthora infestans, "late blight". The picture shows a truss of fruits with early symptoms of the infection - damage to the skin and discolouration. The fruits will not ripen normally. Instead, they will turn brown, shrivel and rot. The picture also shows withered foliage and brown staining of the stalks of the truss (centre, and to right). These symptoms develop throughout the plant as the infection proceeds, resulting in its total collapse and death. Late blight is a serious disease of outdoor grown tomatoes. It occurs most typically following a period of warm wet weather in mid to late summer. P. infestans is also the causative agent of late blight of potatoes, and was responsible for the Irish potato famine of 1845-6, thought to have resulted in one million deaths from starvation