DISEASE MANAGEMENT IN WHEAT AND OTHER SMALL GRAINS A. K. Hagan Auburn University
Leaf Diseases of Wheat
Head Blight, Take All, and Virus Diseases
Diseases of Oats Crown rust Halo Blight Severe Crown Rust Anthracnose Loose Smut Coker 227 Stem Rust Barley Yellow Dwarf Harrison Helminthosporium Leaf Spot
Early Season Disease Management Variety Selection wheat and oat varieties greatly differ in their reaction to diseases, particularly rust. Field Preparation tillage practices and fertility can impact diseases. Planting Date planting early increases risk of rust, powdery mildew, and barley yellow dwarf.
Rust resistant vs susceptible wheat variety Disease Resistant Varieties
Wheat Variety Reaction of Wheat Varieties to Diseases Powdery Mildew Glume Blotch Leaf Rust Wheat Variety Powdery Mildew Glume Blotch AGS 2000 Fair Fair Fair Pioneer 26R15 Good Good Good AGS 2010 Good Good Good Pioneer 26R22 Fair-Good Fair-Good Fair AGS 2020 Good Good Good Pioneer 26R61 Poor Fair Fair AGS 2026 Good Good Good Pioneer 26R87 Good Fair Good AGS 2031 Fair Good Good Progeny Fair Fair Fair AGS 2035 Fair Fair Good Roberts (Forage only) Leaf Rust Good Good Poor AGS 2060 Fair Fair Good SS 8308 Fair Good Poor Baldwin Fair Good Good SS 8641 Good Fair Good Coker 9553 Good Fair Fair USG3021 Good -- Good Dominion Good Good Good USG 3209 Good Fair Poor Fleming Good Fair Good USG 3592 Good Good Good Jamestown Good Fair Poor USG 3295 Good Fair Good Magnolia Poor Fair Poor Terra TV 8558 Poor Good Fair Oglethorpe Fair Good Good
Oat Varieties Horizon 270 Florida 501 Coker 227 Horizon 470? Harrison LA 99011
Fungicide Seed Dressings Fungicide Rate/cwt Crop Comments carboxin + captan + imidacloprin ENHANCE AW carboxin + metalaxyl + PCNB PREVAIL 4.0 oz. Wheat, Oats, Barley 2.5-5 oz. 1.6-3.3 oz. Wheat Oats Hopper box treatment for control of loose smut bunts, seed rots, and seedling diseases of small grains. Hopper box treatment for control of loose smut bunts, seed rots, and seedling diseases. difenoconazole + metalaxyl DIVIDEND EXTREME DIVIDEND XL RTA imidacloprid + metalaxyl + tebuconazole GAUCHO XT tebuconazole + thiram RAXIL-THIRAM 1-4 fl.oz. 2.5-10 fl.oz. 3-4 fl.oz. Wheat and Barley Wheat and Barley 3.5-4.6 fl.oz. Wheat, Barley, Oats Good to excellent fall-season control of powdery mildew, leaf rust, and Septoria leaf blotch when applied at highest rate. Excellent loose smut and bunt control. Suppresses BYD by controlling aphids. Also controls Pythium seed rot and seedling damping off, loose smut, covered bunt, and suppresses early season Septoria diseases, powdery mildew, leaf rust, and root rot. Excellent loose smut and common bunt control. Good seedborne scab control and early season powdery mildew and rust control.
Impact of fungicide seed dressings on smut incidence and yield of Coker 227 oats Fungicide Seed Dressing/cwt seed 2009 Stand Count # plants/ft row Loose Smut Rating* Yield bu/a Non-treated Control 12.1 ab 2.4 a 79.4 b Gaucho XT 3.4 fl oz 9.0 c 1.0 b 130.3 a Raxil MD 5 fl oz 13.5 a 1.0 b 125.8 a Proceed MD with CTD 5 fl oz 10.0 bc 1.0 b 136.4 a Proceed MD Alternative 5 fl oz 11.8 ab 1.0 b 131.1 a 2010 Non-treated Control 8.6 a 2.4 a 83.1 b Gaucho XT 3.4 fl oz 9.1 a 1.0 b 98.8 a Raxil MD 5 fl oz 8.3 a 1.0 b 99.6 a Prevail Hopper Box 4 oz 9.6 a 1.0 b 96.4 a Proceed MD with CTD 5 fl oz 9.6 a 1.2 b 97.0 a Proceed MD Alternative 5 fl oz 9.1 a 1.0 b 98.2 a
Impact of fungicide seed dressings on loose smut incidence and yield of oats - 2012 Fungicide Seed Dressing/cwt seed Stand Count # plants/ft row Loose Smut % heads Yield bu/a Non-treated Control 9.6 a 17.3 a 48.5 b Gaucho XT 3.4 fl oz 10.2 a 1.8 bc 58.3 ab Prevail Hopper Box 4 oz 9.3 a 0.2 cd 63.4 ab Proceed Concentrate 5 fl oz 8.8 a 0.6 cd 58.0 ab Evergol Energy 1 fl oz 9.2 a 0.1 d 70.5 a Raxil MD 5 fl oz 8.6 a 2.6 b 62.0 ab
Fungicide Use Guidelines Target diseases are leaf and glume blotch, rust diseases, and maybe powdery mildew. Yield potential of at least 40+ and preferably 50+ bu/a or grain will be marketed as foundation or certified seed. Most likely to see best economic return in Baldwin-Mobile Co. area. Poor returns in other parts of state unless a severe rust epidemic occurs.
Fungicide Use Guidelines Scout fields weekly beginning at jointing to identify early disease onset. Look at plants at several sites in field. Monitor forecast for weather patterns that favor disease. Choose fungicide appropriate for the control of the target disease. Make one and possibly two applications as needed.
Fungicide Seed Dressing/cwt seed Stand Count # plants/ft row Loose Smut Rating* Yield bu/a 2009 Non-treated Control 12.1 ab 2.4 a 79.4 b Gaucho XT 3.4 fl oz 9.0 c 1.0 b 130.3 a Raxil MD 5 fl oz 13.5 a 1.0 b 125.8 a Proceed MD with CTD 5 fl oz 10.0 bc 1.0 b 136.4 a Proceed MD Alternative 5 fl oz 11.8 ab 1.0 b 131.1 a 2010 Non-treated Control 8.6 a 2.4 a 83.1 b Gaucho XT 3.4 fl oz 9.1 a 1.0 b 98.8 a Raxil MD 5 fl oz 8.3 a 1.0 b 99.6 a Prevail Hopper Box 4 oz 9.6 a 1.0 b 96.4 a Proceed MD with CTD 5 fl oz 9.6 a 1.2 b 97.0 a Proceed MD Alternative 5 fl oz 9.1 a 1.0 b 98.2 a
Fungicide Seed Dressing/cwt seed Stand Count # plants/ft row Loose Smut % heads Yield bu/a Non-treated Control 9.6 a 17.3 a 48.5 b Gaucho XT 3.4 fl oz 10.2 a 1.8 bc 58.3 ab Prevail Hopper Box 4 oz 9.3 a 0.2 cd 63.4 ab Proceed Concentrate 5 fl oz 8.8 a 0.6 cd 58.0 ab Evergol Energy 1 fl oz 9.2 a 0.1 d 70.5 a Raxil MD 5 fl oz 8.6 a 2.6 b 62.0 ab
Fungicide Rate/cwt Crop Comments carboxin + captan + imidacloprin ENHANCE AW 4.0 oz. Wheat, Oats, Barley Hopper box treatment for control of loose smut bunts, seed rots, and seedling diseases of small grains. carboxin + metalaxyl + PCNB PREVAIL 2.5-5 oz. 1.6-3.3 oz. Wheat Oats Hopper box treatment for control of loose smut bunts, seed rots, and seedling diseases. difenconazole DIVIDEND 0.5-1.0 fl.oz. Wheat Good to excellent fall control of powdery mildew, leaf rust, and Septoria leaf blotch when applied at highest rate. Excellent loose smut and bunt control. difenoconazole + metalaxyl DIVIDEND EXTREME DIVIDEND XL RTA 1-4 fl.oz. 2.5-10 fl.oz. Wheat and Barley Good to excellent fall control of powdery mildew, leaf rust, and Septoria leaf blotch when applied at highest rate. Excellent loose smut and bunt control. imidacloprid + metalaxyl + tebuconazole GAUCHO XT 3-4 fl.oz. Wheat and Barley Suppresses BYD by controlling aphids. Also controls Pythium seed rot and seedling damping off, loose smut, covered bunt, and suppresses early season Septoria diseases, powdery mildew, leaf rust, and root rot. ipconazole RANCONA APEX MD tebuconazole + metalaxyl RAXIL MD tebuconazole + thiram RAXIL-THIRAM 5-8.33 fl.oz. Wheat, Barley, Rye, Oats 5-6 fl.oz. Wheat, Barley, Rye, Oats 3.5-4.6 fl.oz. Wheat, Barley, Oats For protection against seed decay, damping-off, and seedling blight as well as bunts and smuts. For suppression or control of seed, seedling, and soilborne diseases. Includes early season control of powdery mildew and rust. Excellent loose smut and common bunt control. Good seed-borne scab control and early season powdery mildew and rust control.