Phytophthora infestans is an oomycete that causes the serious potato isease known as late blight or potato blight. (Early blight, caused by Alternaria solani, is also often called 'potato blight'). It was a major culprit in the 1845 Irish and 1846 Highland potato famines as well as the Great Irish Potato famine of 1845-1852. The organism can also infect tomatoes and some other members of the Solanaceae. It is currently being remedied by genetic engineering, taking a resistance gene from the plant Solanum bulbocastanum and introducing it into the genome of cultivated varieties of the potato.