Wheat Varieties and Management of Stripe Rust. Stephen Guy, Washington State University 2012 Direct Seed Conference Spokane, WA

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1 Wheat Varieties and Management of Stripe Rust Stephen Guy, Washington State University 2012 Direct Seed Conference Spokane, WA

2 Pathogen Environment Host Stripe Rust Weather Variety

3 Stripe rust management program 1. Prepare a stripe rust management program as used for weed or fertility management 2. Integrate a program of: variety selection genetic resistance crop management healthy plants Disease understanding forecasts, weather, scouting Fungicide applications in response to disease 3. Modify program and update regularly for both spring and winter crops 4. Choose and buy inputs that give an economic return.

4 Stripe rust damage can be minimized with a well thought out management program

5 Yield Loss by Stripe Rust and Increase by Fungicide on Winter Wheat, Pullman, WA 2011 Acreage in 2011 Yield (BU/A) Yield loss (%) Yield Inc. (%) Cultivar Acres a % Check Fungicide Difference by stripe rust by fungicide Madsen 65, Bruehl 164, Finley 7, AP700CL 97, Farnum 57, Stephens 26, Cara 17, Westbred , Chukar 13, Rod 26, Brundage 96 47, Paladin 9, Cashup 6, Bauermeister 10, Eltan 243, Masami 39, ORCF , Xerpha 154, ORCF , Tubbs 12, Eddy 17, Tubbs 06 12, PS WA Acreage Mean

6 Summary of 2011 Winter Wheat Yield Loss and Fungicide Study Yield losses >90% without resistance Yield loss >18% in current WA acres without fungicides These are underestimates! Data based on only a single fungicide application

7 Yield Loss by Stripe Rust and Increase by Fungicide on Spring Wheat, Pullman, WA 2011 Acreage in 2011 Yield (BU/A) Yield loss (%) Yield Inc. (%) by stripe Cultivar Acres % Check Fungicide Difference rust by fungicide WA8074 (HRS) WA8124 (SWS) Louise 193, JD 6, Whit 6, Jefferson 39, Kelse 18, Hollis 32, WPB , Diva Babe 3, Tara , Nick 63, Alpowa 15, Hank 19, Lemhi WA Acreage Mean

8 Summary of Spring Wheat Yield Loss and Fungicide Study Yield losses >45% without resistance Yield loss >15% in current WA acres without fungicides These are underestimates! Data based on only a single fungicide application

9 What can we do about stripe rust? 1. Grow resistant varieties Variety trial data (including sites where fungicides were applied) shows that highly resistant lines have consistently yielded higher the past two years Impractical to completely control stripe rust with fungicides on moderately susceptible to susceptible varieties: timing, weather, input costs, label restrictions, product availability, application availability, inadequate monitoring

10 Winter Wheat Stripe Rust Severity in 2011 (5 locations) Distributed by Rust Update list: ratings do change! Look at max or average severities in addition to categorical rating If a other agronomic factors are a coin toss, select varieties with lower severity, high HTAP Soft Winter Wheat Rating Severity (%) HTAP MADSEN R 4 High LEGION R 11 High SKILES R 14 High BRUNEAU MR 12 High AP 700 CL MR 13 High BITTERROOT MR 14 High WB 528 MR 17 Moderate ELTAN MR 18 Moderate BRUNDAGE 96 MR 28 Moderate FINCH MR 30 Moderate ORCF 103 MR 30 Low ROD MR 32 Moderate MASAMI MR 34 Low ORCF 102 MR 34 High STEPHENS MR 40 High XERPHA MS 54 Low LAMBERT MS 56 Low UICF BRUNDAGE S 40 Moderate AP BADGER S 50 No TUBBS 06 S 62 Moderate AP LEGACY S 68 Moderate

11 Spring Wheat Stripe Rust Severity (Average flag leaf infection at 8 locations) Soft Spring Wheat Severity (%) JD 3 WA Alturas 15 Eden 20 Diva 21 Louise 23 Wakanz 31 Whit 34 UI Cataldo 35 Babe 36 Alpowa 39 Zak 52 Nick 71 LEMHI 90 Hard Spring Wheat Severity (%) Lassik 4 WA BR Buck Pronto 14 WA 8074 (Glee) 19 UI Winchester 22 Kelse 28 Jefferson 29 Hollis 34 Bullseye 35 Otis 40 Westbred WB Fuzion 60 Tara Hank 77 LEMHI 90

12 WA8124 Alpowa Can fungicides substitute for genetic resistance to control stripe rust?

13 2011 Hard Spring Wheat Yield in Zone Two fungicide applications Dayton Mayview Walla Walla Average Lassik WA Scarlet Kelse Buck Pronto Bullseye UI Winchester Fx Inc Tara WB Fuzion Jefferson Westbred IDO Cerere WA Hollis Hank

14 2009 Hard Spring Wheat Yield in Zone

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17 What else can we do about rust? 3. Spray fungicides based on rust levels crop development variety/resistance level weather, previous and future production goals costs for material and application Scout, Scout, Scout, Scout, Scout, Scout, Scout

18 What can we do over the next 10 years? 1. Grow resistant varieties 2. Scout fields/watch rust updates pathology and Extension 3. Spray fungicides as needed 4. Select resistant elite lines breeders will be breeding for a combination of seedling and adult plant resistance 5. Keep track of races and race changes pathologists

19 What would I do in 2012? 1. Know the level and type of resistance of the varieties. 2. Keep up on stripe rust updates. 3. Plan to apply inexpensive fungicide with winter wheat herbicide if there is stripe rust in the region. 4. Scout all fields on foot every two four days if conditions are SR condusive starting after herbicide application and through flowering. 5. Apply fungicides at flag leaf timing if there is stripe rust infection in the field and HTAP is not working (for MR+ varieties). 6. If fungicide is not applied at flag leaf, scout closely until flowering and apply if SR kicks in; or if applied, scout and assess necessity of application at flowering (SR levels, variety susceptibility, weather). Be ready to apply fungicide, but only if needed. 7. After flowering, get ready for harvest, your SR management is done for this year, but it s time to assess variety selection for next year and how your strip rust management paid off.

20 Thanks! WSU and USDA Collaborators Washington Grain Commission WSU Extension Variety Testing:

21 What is Stripe Rust? Puccinia striiformis f.sp. tritici Obligate parasite it does not live without a host Wheat is the host for wheat stripe rust Reproduces by spores what you see as rust Spores can survive for weeks Spores need water to infect Usually days from infection to sporulation Ideal temperatures 50 70⁰F Many rust races that determine virulence

22 Stripe Rust 2011 season was the perfect storm! 2010 stripe rust was higher than average crop was harvested late in some areas. Fall 2010 planting was early and allowed fall stripe rust infections that overwintered. Spring 2011 was cool and moist a stripe rust conducive environment. Race shifts in stripe rust increased overall virulence on currently grown cultivars. Fungicide applications started early and were widespread to protect the valuable crop.

23 Disease Environment Host