1. Luis del Río North Dakota State University Developing a Sclerotinia stem rot warning system for canola in North Dakota

3. Photo: www.canolacouncil.org

4. North Dakota canola producing areas DivideBurke RenvilleRoletteTowner Cavalier Mountrail Williams Ward McHenry Pierce Benson Ramsey WellsFoster Eddy Stutsman Griggs McLean Bottineau Rosseau Kittson Marshall Pennington Warren Red Lake Sheridan Nelson Fargo

5. Sclerotinia stem rot disease cycle (Sclerotinia sclerotiorum) A. Lamey

6. Model development  206 fields from 25 locations per year  SSR incidence on 50 plants per field  Annual field survey (third wk August) Disease data collection  SSR mean incidence per location/ year

7.  NDAWN stations  Hourly data on air and soil temp, solar radiation, dew temp, wind speed, etc.  Means and new variables created by periods of 15 days Weather data collection Model development

8.  Logistic regression analysis  Model produced using 177 data points collected between 2001 and 2006  Model validation using cross-validation option of SAS Model development and validation Model development

9.  Risk of SSR development calculated every 3 days  Color maps available to growers through web site during canola flowering period Model forecasting Model development

10. Incidence of Sclerotinia stem rot of canola in North Dakota between 1995 and 2008 Incidence (%) Years Results

11.  Most important weather variables were precipitation and solar radiation  Three models developed, one for second half of June, one for first half of July and a general model Results

12. Percent concordance77 80 83 Percent discordance23 20 17 Somers’ D 0.54 0.59 0.66 Gamma 0.54 0.59 0.66 ParametersModel 1 Model 2 Model 3 Tau- a 0.27 0.30 0.33 c 0.77 0.79 0.83 Results y= 4.08+0.05(rain3)+0.07(rain4)-0.55(solar4)+0.53(rain5) -0.20(solar5)+0.38(rain6)

13. Results

14. Risk estimation North Dakota, 2007 Flowering period Low risk Intermediate risk High risk July 21 July 18 July 15 July 12 July 9 July 6 July 3 June 30 June 27 June 24 Cavalier Towner Rolette 3% 8%4%Mean incidence Results

15. Ward Benson Rosseau Bottineau Benson Towner Cavalier Rollette 33 44 0 100 44 53 76 100 2 1 0 25 7 3 4 8 Prevalence (%)Incidence (%) County SSR county prevalence and incidence, ND 2007Results

16. Cavalier Ramsey Roseau Benson Bottineau Rolla Towner Ward 68 78 100 80 7 100 28 5 4 14 2 1 7 1 Prevalence (%) Incidence (%) County (%) SSR county prevalence and incidence in 2008 47 9 5 15 9 18 20 Fields Results

17. Ward Benson Bottineau Towner Cavalier 13 25 50 60 47 1 2 1 2 3 Prevalence (%)Incidence (%) County SSR county prevalence and incidence, ND 2009Results

18. SSR Prevalence (%) Number of high-risk warnings Association between number of high-risk warnings and SSR prevalence Results

19. Summary  Empirical model developed using weather data  Overall accuracy of model is approximately 75%  Prevalence of high risk warnings associated with higher SSR prevalence

20.  Model improvement is needed  Areas were collaboration is sought: - Modeling leaf wetness duration - Use of Doppler radar data - Quantification of risk of apothecia formation Summary

21. Acknowledgements  Curt Doetkott, ITS  NDSU scouts and county agents  USDA-ARS/Sclerotinia Initiative  North Dakota Canola Growers Association