HGCA Topic Sheet 117 /Summer 2012

U J p u d n a e te 2 d 01 Wheat yellow rust 2 management

Importance Yellow rust can reduce wheat yields by 50% in untreated crops. These losses can be prevented using a combination of varietal resistance and fungicides. In the last few years, changes in the yellow rust fungus (Puccinia striiformis ) have limited the use of varietal resistance to manage the disease, putting greater emphasis on fungicides. High-risk situations Coastal regions stretching from Essex up to Fife are most at risk of yellow rust, with early-sown crops in the region around the Wash being most likely to develop the first early disease outbreaks. Other areas of the UK have a moderate risk of disease, particularly around estuaries or rivers where the humid microclimate suits the yellow rust fungus. Very susceptible varieties can be at risk outside these areas. Action Early-sown crops are at greater risk as fungal spores spread from the previous year’s affected crops and from volunteers in late summer. Mild Monitor all crops regularly for rust winters will increase the risk of the disease overwintering, leading to high symptoms focusing on early-sown infection in the spring. crops in high-risk regions. Cool, damp conditions are conducive to the development of the disease. New yellow rust races appeared in Hot dry spells in the summer are likely to limit its development but such 2011, so check all varieties for conditions may increase the risk of brown rust. yellow rust lesions. Monitor crops regularly for discrete yellow lesions on leaves. Yellow and Diversifying varieties can help you brown rust can be difficult to differentiate in the winter. In the spring, manage priorities for fungicide symptoms commonly occur in lines on the leaf and lesions are typically treatment. yellow in colour. There are no major issues Variety resistance regarding fungicide resistance in New races of the fungus have developed in 2011 that can attack many wheat rusts. popular varieties. New races are commonly named after the variety they Some broad spectrum fungicide attack first. The 'Warrior race' was first recorded in 2011 and the full impact seed treatments offer early on varietal resistance is being examined as part of the UK Cereal Pathogen protection in the autumn. Virulence Survey (UKCPVS). A new race was also detected on KWS Sterling but this variety is not susceptible to the 'Warrior race'. Early spring foliar fungicides are important to start your disease Although the HGCA Recommended List provides useful information on management in high-risk crops. varietal resistance, it can only reflect the previous cropping season. There is no substitute to monitoring crops regularly, including resistant varieties, Azoles, SDHI, strobilurin and to get an accurate picture of the current situation. morpholine fungicides are all effective at protecting crops from New information from the UK Cereal Pathogen Virulence Survey has yellow rust and are best used in highlighted that the 'Warrior race' can attack some varieties currently mixtures. categorised to have good resistance early in their development but the same varieties show good resistance later in the season. This new Eradicating yellow rust is information (Table 1) allows the differentiation of varieties that are challenging and can stress crops, susceptible as seedlings and those that are potentially under threat early in so protect high-risk crops early and the season. maintain protection throughout the season. Diversification of varieties Always consider your local conditions and Not all varieties are susceptible to the same races of yellow rust. Having a consult a professional agronomist if necessary. spread of varieties which are affected by different races can limit the spread of yellow rust between varieties. Information on variety diversification can help determine the risk of spread to prioritise preventative treatments in high disease pressure situations.

A new Diversification Group selection matrix will be published in autumn 2012 to take account of new information. Topic Sheet 117/ Stoneleigh Park HGCA Publications Summer 2012 Warwickshir e CV8 2TL T 0845 245 0009 www.hgca.com E [email protected] Table 1.Yellow rust resistance of HGCA Recommended List 2012/13 Overview winter wheat varieties – Changes in rust races mean varietal Adult plant Adult plant Resistance at Resistance at resistance ratings can change Winter wheat resistance to resistance taking into seedling stage seedling stage to variety yellow rust account the new to the new races detected rapidly. (HGCA 1-9 rating)* 2011 races 2011 races before 2011 – Some varieties with good Oakley 1** Very susceptible Susceptible Susceptible resistance are susceptible to Torch 4 Very susceptible Susceptible Susceptible current races at seedling stage but Solstice 4 Susceptible Susceptible Susceptible develop adult plant resistance later Viscount 4 Susceptible Susceptible Susceptible in the season. Ketchum 5 Susceptible Susceptible Susceptible – Disease spread can be minimised Duxford 5 Susceptible Susceptible Susceptible through the diversification of wheat Gallant 5 Susceptible Susceptible Susceptible varieties. This can help you decide KWS Santiago 6 Susceptible Susceptible Susceptible on which crops to prioritise Einstein 6 Moderately susceptible Susceptible Susceptible remedial action with fungicides. Conqueror 7 Susceptible Susceptible Susceptible – Broad spectrum seed treatments Denman 7 Susceptible Susceptible Susceptible that provide early protection of Gravitas 7 Susceptible Susceptible Susceptible yellow rust should be considered for early-sown susceptible varieties. Cordiale 7 Moderately susceptible Susceptible Susceptible KWS Podium 7 Moderately susceptible Susceptible Susceptible – There have not been any major changes in fungicide resistance in Battalion 7 - Susceptible Susceptible the past few years and early spring Alchemy 8 Susceptible Susceptible Susceptible foliar fungicides remain important. Horatio 8 Susceptible Susceptible Susceptible Warrior 8 Moderately susceptible Susceptible Resistant Further information JB Diego 8 Slightly susceptible Susceptible Susceptible Simon Oxley, HGCA Grafton 8 Slightly susceptible Susceptible Susceptible [email protected] Cocoon 8 Resistant Susceptible Susceptible Invicta 8 Resistant Susceptible Susceptible Rosemary Bayles, NIAB TAG [email protected] Humber 8-Susceptible Susceptible Beluga 9 Susceptible Susceptible Susceptible UK Cereal Pathogen Virulence Claire 9 Susceptible Susceptible Susceptible Survey (funded by HGCA and Fera) KWS Sterling 9 Moderately susceptible Susceptible Resistant Wheat Disease Management KWS Target 9 Resistant Susceptible Susceptible Guide (updated annually) Panorama 9 Resistant Susceptible Susceptible Cereal growth stages – a guide for Scout 9 Resistant Susceptible Susceptible crop treatments (HGCA, 2009) Tuxedo 9 Resistant Susceptible Susceptible Stigg 9 Resistant Resistant Resistant The encyclopaedia of cereal Crusoe 9 Resistant Resistant Resistant diseases (HGCA/BASF, 2008) Relay 9 Resistant --www.hgca.com/diseasecontrol KWS Gator 9 Resistant -- www.hgca.com/varieties *Disease resistance ratings to all common races are given on a 1-9 scale where High risk of high figures indicate the variety shows high resistance to yellow rust yellow rust www.hgca.com/publications **Oakley is no longer included on the HGCA Recommended List but it is still widely Intermediate risk grown and the low resistance will result in a high risk of infection and also pose a of yellow rust While the Agriculture and Horticulture risk to adjacent crops Low risk of Development Board, operating through its HGCA - = No data Blue text = new information, June 2012 yellow rust division, seeks to ensure that the information contained within this document is accurate at the time of printing, no warranty is given in respect thereof and, to the maximum extent Fungicides permitted by law, the Agriculture and Horticulture Development Board accepts no liability for loss, Azole fungicides provide effective protection, including many older azoles damage or injury howsoever caused (including (eg tebuconazole, cyproconazole, epoxiconazole, prothioconazole, that caused by negligence) or suffered directly or indirectly in relation to information and opinions metconazole). contained in or omitted from this document. The newly introduced Succinate Dehydrogenase Inhibitor (SDHI) Reference herein to trade names and proprietary products without stating that they are protected fungicides (eg bixafen in Aviator Xpro, isopyrazam in Seguris and does not imply that they may be regarded as fluxapyroxad in Adexar) are also effective and most strobilurin fungicides unprotected and thus free for general use. No endorsement of named products is intended, nor continue to remain effective (eg pyraclostrobin, picoxystrobin, azoxystrobin). is any criticism implied of other alternative but For short term knock-down, the morpholine fungicides (eg fenpropidin, unnamed products. spiroxamine, fenpropimorph) have good activity when used in a fungicide HGCA is the cereals and oilseeds division of the mixture. Agriculture and Horticulture Development Board.

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