Identifying and Managing Sunflower Diseases Sam Markell, PhD Extension Plant Pathologist North Dakota State University
Take home messages Identification is very important Multiple strategies Rust Resistance, Rotation, Eliminate Wilds, Fungicides work Sclerotinia head rot Rotation, Fungicides (?)
Diseases in Manitoba: 2014 Verticllium wilt Rust Sclerotinia stem Downy Mildew Leaf Spots Sclerotinia head Phomopsis & Phoma 0 20 40 60 80 100 Percent of Fields Source: Khalid Rashid Agriculture and Agri-Food Canada
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 0 20 40 60 80 100
Identification
Downy Mildew
Downy Mildew
Downy Mildew
Downy Mildew Downy Mildew
Downy Mildew
Verticillium Wilt
Verticillium Wilt
Verticillium Wilt
Verticillium Wilt wilt
Verticillium Wilt
Verticillium Wilt
Verticillium Wilt
Verticillium Wilt
Verticillium Wilt
Sclerotinia Wilt, Stalk Rot, Head Rot
Basal Stem Rot Middle Stem Rot Head Rot Sclerotia in soil
Sclerotinia Wilt
Basal Stem Rot Middle Stem Rot Head Rot windborne ascospores apothecia Sclerotia in soil
Basal Stem Rot Middle Stem Rot Head Rot windborne ascospores apothecia Sclerotia in soil
Sclerotinia Stalk Rot
Basal Stem Rot Middle Stem Rot Head Rot windborne ascospores apothecia Sclerotia in soil
Sclerotinia Head Rot
Sclerotinia Head Rot
Phomopsis Stem Canker
Phoma Black Stem
Phoma Black Stem Phoma
Test!
Phomopsis Sclerotinia Phoma
Rust
Rust Life Cycle Aecia Uredinia Pycnia Telia Basiospores Photos: Sam Markell and Loayne Voigt NDSU, and http://www.botany.hawaii.edu/faculty/wong/bot135/basidiumbasidiospore.jpg
Rust
Rust
Rust
NOT Rust
Disease Management
Identification is very important How do you Spray a fungicide Select a resistant hybrid Determine rotation practices
Rotate Breaks down / degrades pathogens Reduces epidemic potential Avoid close rotations with broadleaf crops Canola, pulse crops, soybeans
Destroy Wilds & Volunteers
Genetic Resistance Economic Very effective Rust, Downy Mildew, others?
Fungicides Rust Very effective Sclerotinia Head Rot Less effective
Photos: Markell
0.1% 0.5% 1% 2% 5% 10% 20% 40%
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
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 0 1 2.4 3.4 306 Yellow text indicates time of disease onset All Fungicide Applications were 9 oz Headline
Efficacy Trials CREC 2009 Disease severity Treatment R3-4 R5.5-5-9 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 1555.2 c Proline @ 5.7 fl oz 0 a 0.2 a 1.0 b 1.2 c 8.8 bc 2120.8 a Prosaro @ 6.5 fl oz 0 a 0.2 a 1.0 b 1.1 c 4.7 c 2217.8 a Tebuzol @ 4.0 fl oz 0 a 0.2 a 1.0 b 1.1 c 3.8 c 2118.0 a Headline @ 9.0 fl oz 0 a 0.2 a 0.6c 0.9 c 14.8 b 2083.1 ab Quadris @ 9.0 fl oz 0 a 0.2 a 1.2 b 2.0 b 15.9 ab 1824.5 bc LSD (P 0.05) 0 0.1 0.3 0.8 8.1 283.4
Sunflower Fungicide Trials 2005-2012 (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 R5 2469 2284 NS 0.7 2.23 9.92 *
Yield Difference (lb/a) Rust Severity Difference (%) Headline on Sunflowers 800 600 Change in Yield with Headline Change in Disease with Headline 40 30 400 20 200 10 0 0-200 -10-400 -20
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.
Sclerotinia head rot
Fungicides for Sclerotinia Other crops Fungicide timing is critical Fungicides are somewhat effective Boscalid (Endura) Lance is generally the most consistent and efficacious chemical
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
2013 Sclerotinia head rot trial- Application Timing: (A)- early bloom (B)- 10-12 days after app (A) (C)- 8-10 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 % 56 52 59 49 64 66 a a a a a a 2.8 2.6 2.9 2.4 3.2 3.3 a 2.4 Sev. Index 0-5 a a a a a a 1396 1323 1311 1615 1100 1399 a 1318 Yield lbs/ac a a a a a a a Wunsch et al., 2014
2013 Sclerotinia head rot trial- Application Timing: (A)- early bloom (B)- 10-12 days after app (A) (C)- 8-10 days after app (B) Non-treated check (A) Endura 9oz/ac (A) Endura 9oz/ac (A,B) Endura 9oz/ac (A,B,C) 58 51 41 54 Oakes, ND Incidence % a a a 2.4 2.2 1.6 a 2.3 Sev. Index 0-5 a a a 2109 2166 2740 a 2293 Yield lbs/ac a a a a Wunsch et al., 2014
Take home messages Identification is very important Multiple strategies Rust Resistance, Rotation, Eliminate Wilds, Fungicides work Sclerotinia head rot Rotation, Fungicides (?)
Resources National Sunflower Assoc. of Canada Troy and Darcelle Dr. Khalid Rashid AAFC khalid.rashid@agr.gc.ca Diagnostic cards Google PP1727