Phytophthora infestans

Species of single-celled organism

Phytophthora infestans is an oomycete or water mold, a fungus-like microorganism (oomycete) that causes the serious crop disease known as late blight or potato blight. The Early blight caused by Alternaria solani is also often called "potato blight". Despite its resemblance to true fungi, morphological and molecular classification places this organism among the Stramenopiles; as their cell walls are made of cellulose instead of chitin, and they reproduce through swimming spores, they are evolutionary and functionally closer to algae and diatoms.

From Wikipedia, under CC BY-SA. More on occurri.