- Rust Issues: All 3 rusts are potential constraints.
- Ug99 Status: No Ug99 lineage races have been detected in Lebanon.
Following the confirmed detection of Ug99 (race TTKSK) in Egypt in 2014 (BGRI special newsletter report April 2015) increased vigilance is needed for stem rust in the eastern Mediterranean. Although no confirmed reports of race TTKSK have been obtained from Egypt in 2015, trace amounts of stem rust (race unknown) were detected in the central delta of Egypt in early March 2015. No further reports of stem rust outbreaks have been reported from Egypt in 2015. Crops in Egypt are now approaching maturity, with harvesting occurring between mid April to mid May. However, if any stem rust inoculum were to build up in Egypt then spore deposition models run jointly by the UK Met Office and Cambridge University indicate that there is a risk of onward movement of spores to the eastern Mediterranean basin. Model results show consistent seasonal deposition patterns over the last 12 years, indicating a higher risk, relative to other areas, of spore deposition for Israel, Lebanon, Jordan, eastern Syria and southern Turkey. During the months April and May typically there is a large spatial variation of deposition patterns, with long-distance dispersal of spores that reach eastern Mediterranean countries (see Fig 1 – Data from March, April, May 2014 used as an illustrative example of typical spore dispersal patterns). The most recent spore deposition forecast maps for the period 8 – 14 April 2015, based on confirmed sites for Ug99 (race TTKSK) in Egypt in 2014 agree well with the long-term dispersal trends. Increased surveillance and monitoring is advised in Israel, Lebanon, Jordan, eastern Syria and southern Turkey. Sampling of any stem rust detected in the eastern Mediterranean and rapid race identity confirmation is recommended (either by race analysis on live samples or through the USDA CDL SNP assay for the Ug99 race group). Please contact Dave Hodson, CIMMYT (email@example.com) for more details on sampling options.
The Global Rust Reference Center in Denmark has just published the latest report detailing the results of race analysis for Puccinia striiformis samples submitted during the period January – December 2013. A total of 79 isolates were recovered from 11 countries. The report details race analysis results from a total of 101 isolates from 12 countries obtained during 2012 and 2013.
Key highlights from the report are:
• As in previous years, no detection of virulence to Yr5 and Yr15
• Virulence for Yr10 was observed in East Africa. But it was also noted that virulence for Yr10 was common among European samples from Triticale and virulence for Yr17 was common for European wheat samples.
• Isolates recovered from Afghanistan appeared relatively diverse and additional fine-scale diversity based on modified infection types were quite often observed.
• Isolates considered to belong to the aggressive strain previously reported in many parts of the world were still common. The aggressive strain was also detected frequently in Kenya and in epidemic areas in Ethiopia with additional virulence for Yr1, Yr10, and Yr27. Thus, the combination of virulence for Yr27 and aggressiveness has proven to increase the epidemic
risks in many areas
• Molecular PCR based-markers to detect the aggressive strains are currently being developed by GRRC which will greatly facilitate rapid detection of such isolates (Walter et al. 2014, in preparation).
• Yr27-virulent races were detected in many areas, e.g., Central and South Asia, East Africa and the Middle East.
A copy of the report – Hovmøller 2013: Global Rust Reference Center: Research funded by: Aarhus University,Denmark; CIMMYT; ICARDA – can be found on Wheatrust.org
Surveys covering the main wheat growing areas in Lebanon from north to south were undertaken by Rola El Amil of the Lebanese Agricultural Research Institute (LARI) during the period 7-11th May 2013. A total of 24 locations were surveyed with all crops at the dough stage. Stem rust was widespread throughout the survey areas, being recorded at 13 of the 24 locations (54%). High incidence and severity (>40%) of stem rust was recorded at 8 of these locations. Bread wheat, durum wheat and landraces were all observed to be infected with stem rust. Both yellow and leaf rust were uncommon on the survey. Yellow rust was only recorded at 3 locations in the central and southern areas. Leaf rust was recorded at just 2 locations in the far north, close to the Syrian border.
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.