AGP - 
 

Situation Update: Stem rust widespread in the highlands and west of Yemen

26 Apr 2011

Yemen: Wheat rust surveys undertaken by AREA, Yemen in the key wheat growing areas of the country during October 2010 to March 2011 revealed stem rust to be widespread in the highlands and western areas, but absent in the eastern regions around Seiyun. Of the 33 fields surveyed in the highlands and west of the country in October 2010, stem rust was recorded in 27 (82%) of the fields. Disease severity was high to moderate (>20%) in 13 fields. In contrast stem rust was completely absent from the eastern regions around Seiyun in surveys undertaken in Feb-Mar 2011. Stem rust races present in Yemen during 2010/11 are currently unknown, but samples are undergoing analysis.

   

Situation Update: Ug99 lineage races TTKSK (Ug99), TTKST (Ug99+Sr24) and TTTSK (Ug99+Sr36) confirmed in Tanzania

5 Apr 2011

Three variants in the Ug99 lineage have been confirmed in stem rust samples collected in Tanzania during August 2009 by a team of Tanzanian and international scientists. Races confirmed by the USDA‐ARS Cereal Disease Laboratory, St. Paul, MN, USA were; TTKSK (Ug99), TTKST (Sr24 variant of Ug99) and TTTSK (Sr36 variant of Ug99). Races TTKSK and TTTSK were present in samples from the Hanang, and Ngorongoro areas, whilst race TTKST was present in the Karatu and Monduli areas (Lowe et al forthcoming). All three races have been present in neighbouring Kenya since 2001, 2006, and 2007 respectively. Given the close proximity of wheat areas in Kenya and Uganda known to be infected by stem rust Ug99, and observed regional wind patterns, the results from Tanzania are not unexpected. No crop damage was observed in Tanzania in 2009 due to stem rust. A combination of effective chemical control and early senescence due to drought resulted in the majority of wheat fields surveyed being rust-free apart from a few isolated infected plants. These confirmed results support previous findings which indicate the expected and continued regional spread of Ug99 variants out of Kenya.

   

Stem Rust Situation Update: Stem rust widespread in both Kenya and Eritrea

16 Nov 2010

Survey updates – East Africa

Kenya: Stem rust incidence and severity remains high in Kenya. Expanded surveys (Aug-Sept 2010) by KARI, Njoro staff in the Central and North Rift regions recorded stem rust in 70% of the 122 fields surveyed. Stem rust severity was recorded as moderate (20-40%) or high (>40%) in 29% of the survey fields. From the latest surveys, 75% of the fields were considered to have received some fungicide application.

All of the surveys undertaken in Kenya this year have found stem rust at high incidence and severity. The disease is widespread throughout the wheat growing regions and farmers are very reliant on fungicides for control.  

 

Eritrea: Repeat annual rust surveys were undertaken by NARI, Eritrea staff throughout the Central Highland wheat growing areas in Oct. 2010. In stark contrast to the previous year, stem rust incidence and severity was high. Stem rust was widespread in all the areas surveyed (c.f. complete absence during the Sept. 2009 surveys). Favourable environmental conditions during the current season were undoubtedly a key factor. A total of 92 fields were surveyed and stem rust (both wheat and oat) was recorded at 84% of the sites. Excluding infected oat fields, wheat stem rust was recorded at 49 sites out of 63 (78%). Of these wheat / barley sites, 37 (40%) had moderate (20-40%) or high (>40%) stem rust severity. Extensive sampling was undertaken as part of the Eritrean surveys and race analysis will be undertaken by AAFC, Canada.

 

Details of all surveys can be found in the country survey maps.

   

Wheat Stem Rust Situation Update: High Incidence and Severity of Stem Rust in Lowland Zimbabwe

20 Sep 2010

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. 

 

Survey updates - Caucasus and Central Asia

Additional survey data were received from Azerbaijan and Tajikistan. In Azerbaijan, stem rust was absent from 24 fields surveyed in April 2010. In Tajikistan, 39 fields were surveyed using standard methodology in May 2010. Stem rust at high severity was recorded at 2 sites close to the border with Uzbekistan. Stem rust pathotypes present in Tajikistan are currently unknown.

 

Details of all surveys can be found in the country survey maps.

   

Survey Updates - East Africa

23 Jul 2010

Survey updates – East Africa

Kenya: Stem rust incidence and severity is very high in Kenya. Recent surveys (June 2010) by KARI,Njoro staff in the Narok region recorded stem rust in 80% of the 109 fields surveyed. Stem rust severity was recorded as moderate (20-40%) or high (>40%) in 33% of the survey fields. Extremely susceptible reactions (80-100S) were recorded in 5% of the survey fields. From the survey, 90% of the fields were considered to have received some fungicide application. Reports from the field indicate that farmers who have not sprayed, sprayed late, or used incorrect dosages are experiencing crop losses. Following above normal rainfall in recent months, conditions appear conducive for disease development.

Uganda: Surveys were undertaken by Buginyanya Zonal Agricultural Research and Development Institute and FAO in July 2010. A total of 25 fields were surveyed in Kapchorwa district (east) and Kabale / Kisoro districts (south-west), Uganda. Stem rust was recorded in 64% of the fields surveyed. Highest incidence and severity was recorded in Kabale district, with only trace amounts and low incidence detected in Kapchorwa district. Bread wheat, barley and triticale were all observed with susceptible reactions; however any losses would be minimal due to the advanced stage of most crops. Current race composition in Uganda is unknown, but samples were collected for future race analysis.

 

Survey updates - Middle East, Caucasus, and Central Asia

Surveys were undertaken in Azerbaijan (May/June 2010 – 38 fields), Lebanon (May 2010 – 16 fields) and Uzbekistan (May 2010 – 56 fields). In each country, isolated occurrences of stem rust were detected in farmer’s fields. In Lebanon, occurrence of stem rust at 11 of the 16 survey sites was considered slightly unusual. In Azerbaijan, stem rust at two on-farm sites (score 20SMS, 40SMS) on the Caspian Sea was noteworthy. In Uzbekistan, stem rust (score 40MS) was recorded at a single site in the Fergana Valley. In all cases races involved are currently unknown. Increased surveillance effort may be one factor leading to increased detection, but regular future monitoring and confirmation of races involved is considered important.

 

Details of all surveys can be found in the country survey maps.

   

Wheat Stem Rust - Previous Report

9 Jun 2010

Latest confirmed race analysis results

Confirmed results from race analysis completed in the 2009/10 season are now available. The confirmed spread of Ug99 variants carrying combined Sr31 + Sr24 virulence in Africa continues, along with the continued predominance of these variants in Kenya. The absence of Ug99 from samples collected in Pakistan in 2009 was also confirmed.

 

In Ethiopia, two isolates collected near Meraro in the Rift Valley during October 2007 were confirmed to have combined virulence to both Sr31 and Sr24. Samples were collected by EIAR scientists and analysis undertaken by the Cereal Research Centre, Winnipeg, AAFC, Canada. The race was postulated to be PTKST. This represents the first confirmed occurrence of a Ug99 variant with virulence to Sr24 in Ethiopia.

 

In Kenya, a total of 55 samples were collected in 2009 by KARI scientists but race analysis was only possible on 12 viable samples. Race analysis was undertaken by the Cereal Research Centre, Winnipeg, AAFC, Canada. Races identified were; TTKST (Ug99+Sr24) (50%), PTKST (34%), and PTKSK (16%). Despite the low sample size, the results did indicate the continued predominance of Ug99 variants with combined Sr31 + Sr24 virulence in Kenya (Wanyera et al 2010).

 

In Pakistan, samples were collected during the 2009 season from Sindh and lower Punjab. Isolates were analysed at Murree in Pakistan and at the Cereal Research Centre, Winnipeg, AAFC, Canada. All isolates tested were identified as race RRTTF. This race has also been previously identified in Ethiopia (2007) and in Yemen (2007, 2008). RRTTF has reported virulence on Sr13, Sr36 and SrTmp. It is avirulent on Sr8a, 9e, 22, 24, 25, 26, 27, 31, 32, 39, 40. Preserved urediniospores were also sent to PBI, Uni Sydney, Australia for DNA fingerprinting for Ug99 and negative results were obtained. Combined analyses indicate the absence of Ug99 in the 2009 Pakistan stem rust samples (Mirza et al 2010).  

   

Wheat Stem Rust - Previous Report

17 May 2010

Ug99 Lineage Race PTKST (virulent to Sr31 and Sr24) confirmed in South Africa

A stem rust sample collected from near Greytown, KwaZulu-Natal, South Africa in Nov. 2009 has been confirmed to be Ug99 lineage race PTKST. Samples from another site - Cedara, KwaZulu-Natal, collected in Dec. 2009 showed similar virulence profiles. The confirmed findings have just been published in Plant Disease by Pretorius et al (2010). Race PTKST was only previously known from Kenya, where it was detected in 2008. Race PTKST is notable in that it carries combined virulence for resistance genes Sr24 and Sr31. The published avirulence/virulence profile of race PTKST is:

Avirulent: Sr13, 14, 21, 22, 25, 26, 27, 29, 32, 33, 35, 36, 37, 39, 42, 43, 44, Em, Tmp, and Satu

Virulent: Sr5, 6, 7b, 8a, 8b, 9a, 9b, 9d, 9e, 9g, 10, 11, 16, 17, 24, 30, 31, 34, 38, 41, and McN.

In seedling tests, 59 out of 103 South African cultivars tested were susceptible to race PTKST. It is believed that PTKST may be an exotic introduction into South Africa rather than a single –step mutation from local stem rust races.

   

Stem Rust Undetected in Iraq Field Surveys, March-April 2010

14 May 2010

Stem Rust Undetected in Iraq Field Surveys, March-April 2010

Field surveys undertaken in the main wheat growing governorates in Iraq during March-April 2010 did not detect any stem rust. A total of 18 farmer field sites distributed throughout the country were surveyed (see country map). Stem rust was not recorded at any of the survey sites.

   

Stem Rust at Very Low Incidence in Sudan and Egypt

29 Apr 2010

Stem Rust at Very Low Incidence in Sudan and Egypt

Extensive field surveys undertaken in Sudan (Feb 2010) and Egypt (Feb-Apr 2010) revealed a very low incidence of stem rust in farmers fields. Stem rust was not observed on-farm in Sudan and only trace amounts were recorded at three locations in Egypt (see country maps). A total of 83 locations were surveyed in Egypt and 34 locations in Sudan. Stem rust was present at research stations in both countries. Initial trap plot observations in Egypt gave no indication of the presence of the Ug99 lineage at any sites.

   

Race TTKSF (presumed Ug99 progenitor) confirmed in Zimbabwe

27 Apr 2010

Race TTKSF (presumed Ug99 progenitor) confirmed in Zimbabwe

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.

   

Situation Update Feb 2010

5 Mar 2010

Situation Update Feb 2010

 

Ethiopia: Results of the field surveys undertaken in Sep-Dec 2009 were received. Very comprehensive surveys were undertaken covering virtually all the main wheat growing areas. A total of 877 locations were surveyed. Thirty-five percent of the locations were infected by stem rust. Highest incidence of stem rust occurred in the southern areas, notably the Arsi/Bale region, and the disease was widespread in the Rift Valley area south of Addis. Stem rust was infrequent in northern and western areas. No information on races present is currently available.

Kenya: Field surveys were undertaken in the Mount Kenya and Central Rift Valley regions in Jan-Feb 2010. A total of 90 locations were surveyed. Fifty-nine percent of the locations were infected with stem rust and the disease was widespread throughout the regions surveyed. Approximately 77% of the locations surveyed had been sprayed with fungicides. Confirmation of races present is not yet available.

Yemen: Moderate to high incidence of stem rust was recorded in the screening nursery at Al Kedan on the Red Sea coast in the first week of Feb 2010. Samples are under going race analysis. 

   

Additional Wheat Stem Rust Reports - Africa & Yemen

17 Dec 2009

Additional Wheat Stem Rust Reports - Africa & Yemen 

Additional reports of wheat stem rust were received from several African countries.  In August, wheat stem rust was reported to be widespread in Tanzania. Wheat growing areas in Northern provinces and the Southern highlands both reported the presence of wheat stem rust. In South Africa, wheat stem rust was reported to be widespread in the Southern and Eastern Cape regions during Sept-Oct. One 160 ha field reportedly suffered complete yield loss to stem rust. In Zambia, trace amounts of wheat stem rust were found on 3 breeding lines at Golden Valley Research Station in late October. In all countries, the identity of stem rust races present remains unknown.

In Yemen, reports were received indicating higher incidence of wheat stem rust, compared to 2008, in highland areas during October. No race information is currently available.

   

Wheat Stem Rust Widespread in East Africa

20 Sep 2009

Wheat Stem Rust Widespread in East Africa


In Uganda, high incidence and severity of wheat stem rust have been reported in late August throughout the wheat growing regions. In Kenya, despite drought in many areas, wheat stem rust has been recorded throughout the wheat areas. Unsprayed fields in the North Rift province surveyed in September had high severity of stem rust. The variety KS Mwamba was highly affected.  In both countries, there is no confirmation of races involved but presence of the Ug99 lineage is highly likely. Late rains in Ethiopia delayed planting, surveys will be undertaken in Oct. Southern Africa: Surveys were undertaken in Zambia in late August and Zimbabwe (7-11 Sept. 2009). In Zambia, no stem rust was observed in farmer fields during the survey. Intensive use of fungicides (up to 3 sprays) was reported for commercial farmers. Stem rust was however detected at one research station on 17th Sept. Race identity is currently unknown. In Zimbabwe, stem rust was recorded at 5 locations: Gwebi, Birchenough, Mutare, Nyanga and Harare. Races involved are currently unknown, but race analysis is underway. At Gwebi, this was the first report of stem rust since 2003. At Nyanga, high levels of stem rust infections were observed on small-holder plots.

   
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