Potato blight on leaf. Coloured scanning electron micrograph (SEM) of the potato blight fungus Phytophthora infestans, emerging from a potato leaf. Here, sporangiophores (dark green) are seen growing from the lip-like stomata on the underside of the leaf. Sporangiophores are hyphae, or filaments, which carry sporangia (spore sacs, brown). Leaf hairs, or trichomes, are the large green/yellow structures. The first widespread infection of commercial importance was in 1845, when most of Europe suffered decimated potato crops due to blight. Prevention of blight depends on spraying with fungicide and selective breeding. Magnification: x140 at 5x7cm size. x550 at 4.5x10"~PORTRAIT"