During 2013 (Jan-Sept.) staff from KARI, Njoro, led by Ruth Wanyera, carried out extensive annual rust surveys throughout the Kenyan wheat growing areas. A total of 333 fields were surveyed for rusts. stem rust continues to be the predominant disease recorded on the Kenyan surveys; present in 160 of the 333 fields visited (48%). Stem rust was widespread – being observed in all the areas surveyed, but the Central Rift Valley region accounted for most of the high severity observations. Moderate (20-40%) or high (>40%) severity of stem rust was recorded in 84 of the fields visited. Favorable environmental conditions may have contributed to the relatively high severity of stem rust observed on the 2013 surveys. Yellow rust was only recorded in 22 of the fields visited (7%), with 12 of the infected fields showing moderate or high levels of severity. Similarly, leaf rust was only recorded in 21 fields (6%) and 11 of the infected fields had moderate or high disease severity.
Data on known cultivars recorded in the survey fields indicated that the recently released (2011, KARI release), high-yielding, rust-resistant cultivar “Kenya Robin” is gaining increasing popularity among Kenyan wheat farmers. “Kenya Robin” was observed in 51 of the 333 fields surveyed (15%), with a widespread distribution throughout the wheat growing areas. Comparison with equivalent survey data and known cultivars from 2009-2013 (Fig. 1) indicated that susceptible cultivars (“KS Mwamba” & “NJBWII“) still predominate, but the percentage of fields observed with the highly susceptible cultivar “KS Mwamba” appears to be declining.