Potato blight. Coloured scanning electron micrograph (SEM) of the potato blight fungus (Phytophthora infestans) on a potato plant leaf (Solanum tuberosum). The fungal sporangiophores (centre) are seen emerging from a stoma of the leaf (lower centre). Their sporangia pods (upper centre) eventually become detached and float off, spreading the infection to other potato plants. Leaf hairs, or trichomes (brown), are seen at right and top left. Phytophthora infestans infection results in the discolouration and lesion of potato plant leaves, and was responsible for the Irish potato famine of 1845. Magnification: x282 at 5x7cm size.