Mehran Patpour (Global Rust Reference Center in Denmark) and co-authors have just published details of the emergence and spread of virulence to SrTmp in the Ug99 race group in Africa. The note is now available as a First Look in Plant Disease  (see http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS-06-15-0668-PDN). The report details the results of combined race analysis undertaken by the GRRC, Denmark and the USDA-ARS Cereals Disease Lab, Minnesota on 84 stem rust samples collected in 2014 from Kenya, Uganda, Rwanda and Egypt.

Seedling reaction of Race TTKTK on selected differentials (Photo: GRRC, Denmark)

The presence of two new Ug99 race group variants – race TTKTK (Ug99 + virulent on SrTmp) and race TTKTT (Ug99 + virulent on SrTmp and Sr24) were confirmed in Kenya. Race TTKTK was also confirmed in Uganda, Rwanda and Egypt. Detection of these new variants in the Ug99 race group across several countries in a single year indicates the relevance of coordinated surveillance activities and also indicates potentially very rapid geographical dispersal of race TTKTK.