Identifying and Managing Sunflower Diseases. Sam Markell, PhD Extension Plant Pathologist North Dakota State University

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2 Identifying and Managing Sunflower Diseases Sam Markell, PhD Extension Plant Pathologist North Dakota State University

3 Take home messages Identification is very important Multiple strategies Rust Resistance, Rotation, Eliminate Wilds, Fungicides work Sclerotinia head rot Rotation, Fungicides (?)

4 Diseases in Manitoba: 2014 Verticllium wilt Rust Sclerotinia stem Downy Mildew Leaf Spots Sclerotinia head Phomopsis & Phoma Percent of Fields Source: Khalid Rashid Agriculture and Agri-Food Canada

5 Source: Khalid Rashid Agriculture and Agri-Food Canada Diseases in Manitoba: 2014 Verticllium wilt Rust Sclerotinia stalk rot Downy Mildew Leaf Spots Sclerotinia head rot Phomopsis & Phoma

6 Identification

7 Downy Mildew

8 Downy Mildew

9 Downy Mildew

10 Downy Mildew Downy Mildew

11 Downy Mildew

12 Verticillium Wilt

13 Verticillium Wilt

14 Verticillium Wilt

15 Verticillium Wilt wilt

16 Verticillium Wilt

17 Verticillium Wilt

18 Verticillium Wilt

19 Verticillium Wilt

20 Verticillium Wilt

21 Sclerotinia Wilt, Stalk Rot, Head Rot

22 Basal Stem Rot Middle Stem Rot Head Rot Sclerotia in soil

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24 Sclerotinia Wilt

25 Basal Stem Rot Middle Stem Rot Head Rot windborne ascospores apothecia Sclerotia in soil

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27 Basal Stem Rot Middle Stem Rot Head Rot windborne ascospores apothecia Sclerotia in soil

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31 Sclerotinia Stalk Rot

32 Basal Stem Rot Middle Stem Rot Head Rot windborne ascospores apothecia Sclerotia in soil

33 Sclerotinia Head Rot

34 Sclerotinia Head Rot

35 Phomopsis Stem Canker

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37 Phoma Black Stem

38 Phoma Black Stem Phoma

39 Test!

40 Phomopsis Sclerotinia Phoma

41 Rust

42 Rust Life Cycle Aecia Uredinia Pycnia Telia Basiospores Photos: Sam Markell and Loayne Voigt NDSU, and

43 Rust

44 Rust

45 Rust

46 NOT Rust

47 Disease Management

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49 Identification is very important How do you Spray a fungicide Select a resistant hybrid Determine rotation practices

50 Rotate Breaks down / degrades pathogens Reduces epidemic potential Avoid close rotations with broadleaf crops Canola, pulse crops, soybeans

51 Destroy Wilds & Volunteers

52 Genetic Resistance Economic Very effective Rust, Downy Mildew, others?

53 Fungicides Rust Very effective Sclerotinia Head Rot Less effective

54 Photos: Markell

55 0.1% 0.5% 1% 2% 5% 10% 20% 40%

56 Percent disease severity (upper 4 leaves, according to diagrams) Yield Treatment R3.5 R5 R6-7 R9 (lb/a) Untreated Control 1 wk before dis (R3.5) Approx 1% sev (R5) Approx 7% sev (R6-7) R3 + R5.2 + R6.0 LSD Yellow text indicates time of disease onset All Fungicide Applications were 9 oz Headline

57 Percent disease severity (upper 4 leaves, according to diagrams) Yield Treatment R3.5 R5 R6-7 R9 (lb/a) Untreated Control 0 a 1.8 ab 8.7 a 16.5 a 1501 a 1 wk before dis (R3.5) 0 a 0.8 bc 4.1 b 13.9 a 1720 ab Approx 1% sev (R5) 0 a 0.8 bc 1.3 c 3.6 bc 1899 b Approx 7% sev (R6-7) 0 a 2.7 a 6.0 b 4.6 b 1440 a R3 + R5.2 + R6.0 0 a 0.4 c 0.4 c 0.9 c 1941 b LSD Yellow text indicates time of disease onset All Fungicide Applications were 9 oz Headline

58 Efficacy Trials CREC 2009 Disease severity Treatment R3-4 R R6 R6-7 R7-8 Yield (lb/a) Non-treated Control 0 a 0.2 a 1.6 a 6.9 a 23.8 a c 5.7 fl oz 0 a 0.2 a 1.0 b 1.2 c 8.8 bc a 6.5 fl oz 0 a 0.2 a 1.0 b 1.1 c 4.7 c a 4.0 fl oz 0 a 0.2 a 1.0 b 1.1 c 3.8 c a 9.0 fl oz 0 a 0.2 a 0.6c 0.9 c 14.8 b ab 9.0 fl oz 0 a 0.2 a 1.2 b 2.0 b 15.9 ab bc LSD (P 0.05)

59 Sunflower Fungicide Trials (Markell, Friskop, Endres, Halley, Schatz, Wunsch, Schaefer) Year Locatio n Headline (plus NIS) NTC LSD Rate Crop Yield/ (fl oz/a) stage A Yield/A 0.05 Rust at R5 % Sev. % Rust Sev. at R7 Headline NTC LSD 2008 Carr f 9 R NS *

60 Yield Difference (lb/a) Rust Severity Difference (%) Headline on Sunflowers Change in Yield with Headline Change in Disease with Headline

61 Fungicides for Rust If rust severity reaches 1% on the upper four leaves at or before R5, a fungicide application is likely to be economic Use diagrams as guide Strobilurins and Triazoles are good.

62 Sclerotinia head rot

63 Fungicides for Sclerotinia Other crops Fungicide timing is critical Fungicides are somewhat effective Boscalid (Endura) Lance is generally the most consistent and efficacious chemical

64 Fungicides for Sclerotinia Sunflower Most sensitive crop Fungicide timing is more difficult Fungicides are somewhat effective, but Architecture is a challenge Coverage is a challenge

65 2013 Sclerotinia head rot trial- Application Timing: (A)- early bloom (B) days after app (A) (C) days after app (B) Non-treated check (A) Endura 9oz/ac (A) Endura 9oz/ac (A,B) Endura 9oz/ac (A,B,C) Omega 16 fl oz/az (A) Omega 16 fl oz/az (A,B) Omega 16 fl oz/az (A,B,C) 49 Carrington, ND Incidence % a a a a a a a 2.4 Sev. Index 0-5 a a a a a a a 1318 Yield lbs/ac a a a a a a a Wunsch et al., 2014

66 2013 Sclerotinia head rot trial- Application Timing: (A)- early bloom (B) days after app (A) (C) days after app (B) Non-treated check (A) Endura 9oz/ac (A) Endura 9oz/ac (A,B) Endura 9oz/ac (A,B,C) Oakes, ND Incidence % a a a a 2.3 Sev. Index 0-5 a a a a 2293 Yield lbs/ac a a a a Wunsch et al., 2014

67 Take home messages Identification is very important Multiple strategies Rust Resistance, Rotation, Eliminate Wilds, Fungicides work Sclerotinia head rot Rotation, Fungicides (?)

68 Resources National Sunflower Assoc. of Canada Troy and Darcelle Dr. Khalid Rashid AAFC Diagnostic cards Google PP1727