June 1, 2012: Ethiopia rust survey summary, 2011 main season – Yellow rust levels remain high

Posted on by June 28, 2012

Following the widespread yellow rust epidemics observed in the 2010 main season, extensive wheat rust surveys were undertaken by staff  from 13 different institutes throughout Ethiopia. These surveys were once again coordinated by Dr Getaneh Woldeab of the EIAR Ambo Research Station. A total of 719 sites were surveyed, with all the major wheat growing areas covered by the surveys. Whilst not at the same level of disease pressure as 2010, yellow incidence and severity remained very high in certain areas. Continued widespread cultivation of susceptible cultivars like Galema and Kubsa was almost certainly a factor.

Yellow rust once again predominated, being recorded at 414 of the sites surveyed. A larger proportion of sites were recorded with only low disease severity (1-20%) compared to 2010, but even so approximately 40% of the sites with yellow rust reported moderate or high disease severity (>20%). High (>40%) disease severity was reported  from 81 sites (cf 200 sites in 2010). Yellow rust was still widely distributed, but more concentrated in the western highlands – Oromyia and Amhara regions – rather than in the eastern highlands of Arsi and Bale. As in 2010, the northern areas of Tigray were relatively free of yellow rust.

As in 2010, stem rust and leaf rust were recorded in approximately equal proportions on the survey. Stem rust was recorded at 158 sites and leaf rust at 144 sites. Moderate or high (>20%) stem rust severity was recorded at 29 locations. For both diseases the majority of records were of low disease severity (1-20%). Stem rust was again concentrated in the southern areas, south of Addis Ababa.  Leaf rust was more widely distributed occurring throughout the wheat growing areas of Ethiopia, apart from the northern areas of Tigray.

May 14, 2012: Initial rust surveys in Bhutan find no trace of stem rust, but both yellow and leaf rust widespread

Posted on by May 29, 2012

Cereal rust surveys were undertaken by the National Plant Protection Centre, Department of Agriculture, Ministry of Agriculture and Forest, Semtokha, Thimpu, Bhutan and the Research and Development Centre, Bajo, Wangduephodrang in collaboration with the Durable Rust Resistance in Wheat (DRRW) project during the period 17-21st April 2012. Surveys were undertaken in the wheat/barley/oat growing areas of five Dzongkhag’s in western Bhutan (Haa, Paro, Punakha, Gasa, Wangdi Phodrang). A total of 26 individual sites were visited, with several cereal fields surveyed for diseases at each location.  Surveys were conducted in agricultural areas, primarily along river valleys, at elevations ranging from 1200m to 2700m. The majority of the cereal crops surveyed were at the flowering-milk growth stage, although at higher elevations crops were observed at earlier growth stages (tillering). Berberis sp. bushes in close proximity to cereal crops and by the roadside were checked for aecial infections throughout the survey.

No stem rust was observed at any of the survey sites visited. Individual pustules with unusual morphology indicative of possible stem rust infections were collected at several sites, but subsequent microscopy at the NPPC laboratory indicated that all such pustules were actually leaf rust.

Stripe (yellow) rust was the most widespread cereal rust, being observed at 13 out of the 26 sites visited. Highest incidence and severity of stripe rust was observed in Punakha Dzongkhag. Four of the sites visited in Punakha exhibited moderate to high severity of disease. The commonly grown cultivar “Sonalika” was susceptible to stripe rust.  Both bread wheat and barley were infected with stripe rust. Low incidence and severity of stripe rust was also observed in the southern part of Paro Dzongkhag.

Leaf rust was observed at 11 out of the 26 sites visited. Distribution of the disease essentially mirrored that observed for stripe rust, with most observations occurring in Punakha Dzongkhag. Leaf rust was also recorded at two sites in Paro Dzongkhag. At all sites, except Wangdue research station, only low incidence and severity of leaf rust were recorded on the survey. The commonly grown cultivar Sonalika was considered moderately susceptible to susceptible to leaf rust.

Berberis spp. were common in the survey areas, present along roadsides and in close proximity to cereal crops. Berberis spp. infected with rust aecia were observed at three distinct locations – one location in southern Punakha (Omtekha village)  and two locations in Paro (Shabdrujedingkha and Susuna) . All infected Berberis had broad-leaf morphology, but at least two different species were considered to be susceptible to aecial infections. None of the narrow-leafed Berberis sp. examined had any signs of aecial infection.

Samples of cereal rusts (wheat stripe rust, barley stripe rust, wheat leaf rust and barley leaf rust) were collected from all infected sites. Samples of Berberis leaves infected with aecia were also collected. Samples were sent under permit to international rust laboratories in the USA, Denmark and India for subsequent race analysis.

Read full survey report – click HERE

May 1, 2012: Uganda – High severity of stem rust in both the eastern and south-west regions, yellow rust in both regions

Posted on by May 16, 2012

During the period 12th January 2012 to 7th February 2012 Buginyanya ZARDI staff – W.W. Wagoire (Team Leader), A. Wasukira (Pathologist), B. Chemayek and S. Wobibi with the cooperation of field staff from the wheat growing districts, undertook a wheat rust survey in Uganda’s main wheat growing areas.   The survey route included sites in Kapchorwa, Kween and Bukwo in the east and, Kabale and Kisoro in the south west.  In the east, the wheat crop was mainly at post dough stage while in the southwest just a few fields with mature small grains could be accessed as this period did not constitute the main wheat growing season.  A total of 30 fields were surveyed using the standard BGRI survey methodology.  And all survey locations were geo-referenced using GPS. All the 16 fields surveyed in the east were bread wheat, whereas in the west of the 14 fields surveyed 5 were bread wheat, 3 Triticale, 5 barley and 1 other ( a grass). stem rust predominated, being recorded in 23 out of the 30 fields surveyed (77%) and was widespread in both the east and the south-west. High (>40%) or moderate (20-40%) severity was recorded in 11 of the fields surveyed. Compared to previous surveys undertaken in 2010 higher incidence and severity of stem rust was recorded in the eastern region. yellow rust was recorded in 10 of the 30 fields surveyed (33%), occurring in both the east and the south-west. High (>40%) or moderate (20-40%) severity of yellow rust was recorded in 6 of the fields surveyed. Similar to stem rust, higher incidence and severity of yellow rust was recorded in the eastern region compared to the previous surveys undertaken in 2010. Leaf rust was the least common rust observed on the surveys, present in only 5 fields (17%).  A total of 25 stem rust samples were collected for DNA analysis and sent to the Cereals Disease Lab, Minnesota for further analysis.

Dec 5, 2011: Survey summary, Kenya 2011 – Stem rust predominates, but indications of effective control in some areas

Posted on by April 30, 2012

Kenya: During 2011 (Jan-Sept.) staff from KARI, Njoro carried out extensive rust surveys throughout the Kenyan wheat growing areas. A total of 466 fields were surveyed for rusts. stem rust was the predominant disease recorded on the surveys; present in 306 of the 466 fields visited (66%). Stem rust was widespread – being observed in all the areas surveyed, but compared to previous years disease severity was reduced. Only 56 of the 466 fields visited (13%) recorded stem rust severity as moderate (20-40%) or high (>40%) [c.f. moderate or high severity in 40% of fields in 2007, 23%  in 2008, 33% in 2009, 26% in 2010]. In the North Rift region, surveyors considered that most of the farmers were undertaking effective chemical control of stem rust and this was leading to a noticeable decrease in the incidence and severity of the disease. In addition, two new rust resistant varieties (Eagle-10 and Robin) were officially released by KARI, Njoro in 2011. It is hoped that both of these, along with future forthcoming varieties, will give Kenyan wheat farmers more options for rust control.

Oct 1, 2011: Ug99 lineage races TTKST & PTKST (combined Sr31 + Sr24 virulence) confirmed in Eritrea

Posted on by April 3, 2012

Photo Credit: Prof. Z.A. Pretorius

Analysis undertaken by AAFC, Canada on samples collected by NARI, Eritrea in Oct. 2010 has confirmed the presence of Ug99 lineage races TTKST and PTKST in Eritrea. Wolday et al (2011) report the findings in the journal Plant Disease. Both races have combined virulence for the widely deployed stem rust resistance genes Sr31 and Sr24. The two races differ only in their reaction to the Sr21 gene. This first confirmation of TTKST and PTKST in Eritrea is important because it represents further geographical spread of Ug99-related races. On the basis of observed occurrence and postulated migration routes of the original Ug99 (race TTKSK), the confirmed presence of TTKST and PTKST in Eritrea increases the possibility for range expansion out of Africa by crossing the Red Sea and into the Arabian Peninsula.

Sept. 30, 2011: Zimbabwe rust survey summary – Stem rust persists in the Lowveld, leaf rust widespread

Posted on by June 26, 2012

Photo Credit: B. Mutari

Wheat rust surveys were undertaken by the Crop Breeding Institute and Plant Protection Research Institute throughout the key wheat growing areas of Zimbabwe during the period 19th – 24th September 2011. The primary focus of the surveys was to assess the status of wheat stem rust in Zimbabwe compared to the situations in 2009 and 2010 and to monitor the potential spread of new virulent races of wheat stem rust (Ug99 race lineage) in Zimbabwe and Southern Africa as a whole. In the survey area, wheat was grown at elevations ranging from 413m to 1535m. A total of 20 wheat fields, distributed throughout the main agro-ecological zones, were surveyed using standard BGRI survey methodology. Wheat stem rust was recorded at 6 of the 20 survey sites – Gwebi Variety Testing Center (GVTC), Chiredzi Research Station, Chisumbanje Research Station, Birchenough*2, and Sisal Farm Mutare. For the third year running, stem rust was widespread in the Lowveld, with 4 out of 6 Lowveld sites below 800m recording the disease. High or moderate stem rust severity (>20%) was recorded at 3 of these Lowveld sites. At Chiredzi, high levels of stem rust infections were observed in Preliminary Variety Trials with SC Sekuru (improved variety) showing highly susceptible reactions together with three other experimental lines. At GVTC, low incidence of stem rust was observed in Intermediate Variety Trials with Dande (improved variety) and four other experimental lines showing highly susceptible reactions. Low incidence and very high severity of stem rust was recorded at Sisal farm in a CIMMYT rust resistance screening nursery. Trace amounts of stem rust were recorded at Chisumbanje Research Station in contrast to last year where very high incidence and severity was recorded at the same station. Stem rust samples were collected and sent for molecular diagnostic analysis and  race analysis.. In addition to stem rust, leaf rust was recorded at 13 of the 20 sites surveyed. Severe leaf rust infections were observed at 4 of the survey sites. Powdery mildew was also regularly recorded at survey sites. No stripe rust was observed at any survey location.

Sep. 25, 2011: Leaf rust widespread, but stem rust undetected on Mozambique surveys in September 2011

Posted on by April 3, 2012

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.

July 31, 2011: Georgia rust survey summary – Stem rust predominates, notably in the Central Region

Posted on by June 26, 2012

Photo Credit: Z. Sikharulidze

Wheat rust surveys were undertaken by staff from the Georgian Institute of Plant Immunity (GIPI) during June and July 2011. The surveys covered the wheat growing areas of Eastern Georgia. A total of 67 wheat fields were surveyed using standard BGRI survey methodology. stem rust was found to be the predominant rust disease on the surveys, being recorded in 60% of the fields visited. Highest incidence and severity of stem rust was recorded in the Central Valley, stretching North-west from Tbilisi (see the Survey Mapper tool for distribution). The majority (n=32) of the stem rust fields had low severity (<20%), however 8 fields were recorded with moderate or high severity (>20%). Precise race composition of the Georgian stem rust population is currently unknown, although it is likely to be local races.

Yellow rust and leaf rust were also recorded on the surveys. Yellow rust was found to be present in 24 of the fields surveyed and leaf rust in 10 of the fields. Leaf rust was at low severity in all of the fields where it was present. Yellow rust was recorded at moderate or high severity in just 3 locations.

July 15, 2011: Tajikistan rust survey summary – Low levels of yellow rust

Posted on by June 28, 2012

Wheat rust surveys were undertaken throughout the main wheat growing areas of Tajikistan by staff from the Tajikistan Agrarian University. A total of 22 sites were surveyed, covering both the northern and southern wheat growing regions. yellow rust was the only rust recorded on the survey. The disease was widely distributed, but only low severity (1-20%) of disease was recorded at all the sites where yellow rust was present.

July 1, 2011: Iraq rust survey summary – Yellow rust predominates, especially in the North-Eastern areas

Posted on by June 26, 2012

Extensive wheat rust surveys were undertaken throughout the wheat growing regions of Iraq during May 2011. A total of 344 sites were surveyed using standard BGRI survey methodology. Yellow rust dominated the surveys, being recorded at 96 of the sites visited. The disease was widely distributed, but highest levels of incidence and severity were recorded in the North-eastern areas adjacent to the Iranian border. A total of 42 sites had moderate or high (>20%) severity levels, virtually all of which were clustered together in the North-eastern region.

Leaf rust was also widespread, being recorded at 40 of the sites visited. However, only low or moderate levels of disease severity were recorded.

Stem rust was recorded at a single site near Mosul, with low incidence and severity reported.