Diseases affecting the foliage include rust and smut, downy mildew, and white tip disease. He also made cameo appearances in "Smut" and "Dirty Love". Barley varieties with resistance to loose smut are also commercially available. "Ustilago maydis" is a pathogenic plant fungus that causes smut disease in maize and teosinte. Tilletia is a genus of smut fungi in the Tilletiaceae family. Corn smut contains much more protein than regular corn does. Therefore, special precautions need to be taken during irrigation to prevent spreading of the smut. The swelling occurs because of infection with the smut fungus "Ustilago esculenta". The amino acid lysine, of which corn contains very little, abounds in corn smut. The consumption of corn smut originated directly from Aztec cuisine. The Ustilaginomycotina are most (but not all) of the former smut fungi and the Exobasidiales. Sugarcane smut is disseminated via teliospores that are produced in the smut whip. This was done to reduce the deposit of soot and smut on her decks. Progress has been made in studies of the molecular basis of sugarcane smut resistance. It was the inspiration for Michael Bishop's 2005 story "Bears Discover Smut".