Latest Survey Data
- Rust Issues: Leaf rust is a constraint to wheat production.
- Ug99 Status: SSR analysis of DNA samples collected in 2010 confirmed the presence of the Ug99 lineage (Mukoyi et al 2011). Exact race is unknown, but most likely either TTKSF, TTKSK or PTKST.
Situation Updates:
Mozambique: Wheat rust surveys were undertaken by IIAM and CIMMYT in the key wheat growing areas of Manica and Tete provinces, Central Mozambique during the period 16-20 September 2011. The surveys were a repeat of surveys initiated in 2010, which confirmed the presence of Ug99 lineage races in Mozambique in 2010. In the survey area wheat was grown in dispersed, small plots at elevations ranging from 612m to 1681m. Virtually all wheat farmers were growing the same variety; SC Nduna, the only exception was a very limited number of fields planted to the cultivar “Zambesi” in Rotanda. A total of 33 wheat fields were surveyed using standardized BGRI methodology. Two wheat variety trial sites (IIAM Rotanda and IIAM Sussendenga) were also included in the survey. Wheat maturity at the time of the survey ranged from flowering to maturity, with harvest underway in Rotanda. Wheat stem rust was not observed at any of the sites surveyed in 2011. Wheat leaf rust was widespread on SC Nduna being recorded at 25 of the 33 sites surveyed. The Catandica area was the only area surveyed in which leaf rust was not observed. Leaf rust infections were most widespread and severe in Tsangano. No stripe (yellow) rust was recorded at any of the survey locations.
Survey updates – Southern Africa
Mozambique: Wheat rust surveys were undertaken by IIAM, Mozambique and FAO in the key wheat growing areas of Manica and Tete provinces, Central Mozambique during the period 26th August – 1st September 2010. Wheat in Mozambique is grown in dispersed, small plots typically in remote highland areas. The Tsangano region bordering Malawi contained the highest density of fields. A total of 24 wheat fields were surveyed using standardized methodology. Wheat stem rust was not widespread and only positively recorded at one site; Rotanda, in Sussendenga district. Here a tall local wheat variety (Sitsonko) showed a highly susceptible reaction. It was noteworthy that virtually all farmers in Mozambique were growing the same variety; SC Nduna.
Zimbabwe: Wheat rust surveys were undertaken by the Crop Breeding Inst, SeedCo and FAO in the key wheat growing areas of Zimbabwe during the period 4th-9th September 2010. A total of 27 wheat fields, distributed throughout the main agro-ecological zones, were surveyed using standardized methodology. Wheat stem rust was recorded at 12 of the 27 survey sites, being much more prevalent and widespread than in the previous 2009 season. Stem rust was widespread in the Lowveld, with 8 out of 9 Lowveld sites (elevation below 800m) recording the disease. High or moderate stem rust severity (>20%) was recorded at 6 of these Lowveld sites. Highly susceptible reactions were observed on improved varieties such as SC Stallion. Very high incidence and severity of stem rust was recorded at Chisumbanje Research Station (Photo). Trace amounts of stem rust were also recorded at 4 highveld sites (Gwebi VTC, Rattray Arnold, Kadoma, Nyanga). Stem rust samples were collected at all sites where the disease was present. Until completion of the laboratory analysis the actual identity of stem rust pathotypes present in Zimbabwe is unknown. Given the recent (2009) confirmation of Ug99 lineage race PTKST (combined virulence to both Sr31 and Sr24) in South Africa, identification of the Zimbabwe pathotypes is a high priority.