Out of Uganda: An Aggressive Crop Killer That Threatens Global Food Fungal disease in wheat crops has been a serious but controllable problem, but a newer strain of what’s called “stem rust” has scientists worried. January 8, 2018 by Kerstin Hoppenhaus & Sibylle Grunze The video below is the first part in a six-part series examining the scourge of Ug99, a type of fungus that causes disease in wheat crops — one that scientists worry could threaten global food supplies. Visit our series archive for all published episodes. There was a time when one of the most dangerous crop diseases