stem rust samples collected near Harare in Sept 2009 have been confirmed as race TTKSF, the presumed progenitor of Ug99. Analysis undertaken by the University of the Free State, South Africa and the USDA-ARS, Cereals Disease Lab, Minnesota, USA confirmed the presence of this race. TTKSF is similar to Ug99 except for avirulence on Sr31. TTKSF had only previously been known from South Africa, where it has become the most prevalent stem rust race since its detection in 2000.