What causes UG99?

A fungus called Puccinia graminis causes stem rust in cereal crops. One of its races is TTKS which is also known as Ug99 (it was detected in Uganda in 1999) which has currently become an epidemic in Africa, Asia and Middle East Countries. It’s a serious problem as large number of people is dependent upon the wheat crop. Unlike other rusts, which only partially affect crop yields, UG99 can bring 100% crop loss and that is why raises concern. It was first noted in Uganda and a few years back 80% loss was caused in Kenya.