Stategic Planning for Mitigation of Fusarium Head Blight in Wheat Anita Brûlé-Babel Department of Plant Science One University. Many Futures.
FHB Issue Prior to 1980 FHB epidemics were sporadic Since early 1980 s in Ontario and early 1990 s in Manitoba severe FHB epidemics have occurred more frequently Recent increase in Saskatchewan and Alberta Losses in yield and end-use quality Mycotoxin contamination affects food and feed safety, and reduces grain marketability Losses to Canadian wheat industry in excess of $1 billion (Clear et al. 2009)
Symptoms Premature bleaching White, pink or orange spores Fusarium damaged kernels
Ascospores - primary inoculum - can travel kilometers Conidia - disperse over short distances Source: Trail, 2009
Multiple Species Fusarium graminearium Main species of concern in Eastern Canada, Manitoba and Southeast Saskatchewan Produces primarily deoxynivalenol (DON) F. culmorum Adapted to cooler conditions Produces primarily deoxynivalenol (DON) F. avenaceum Produces primarily moniliformin (MON) F. poae Produces nivalenol (NIV) and other toxins Septoria nodorum Symptoms may be confused with FHB Other species and toxins also present in low amounts
Disease Triangle Influences Management Strategy All components of disease triangle required for disease to occur Disease Environment
Most Susceptible Stage Flowering (Anthesis) Need warm, moist conditions Precipitation 16 to 32 o C Night temperature above 10 o C High humidity Infection possible to soft dough stage May not see same symptoms but mycotoxins may be present
FHB Risk Forecast Based mainly on conditions suitable for F. graminearum Duration of rainfall (hours) and temperatures between 15 and 30 C for 7 days prior to anthesis http://www.gov.mb.ca/agriculture/crops/seasonal-reports/fusarium-head-blight-risk-forecast-archives.html
How can I manage risk of FHB infection? A. Spread out planting dates B. Use practices that promote uniform stands (i.e. all plants/spikes at same stage) C. Neither A nor B D. Both A and B E. Don t know
Disease Triangle Influences Management Strategy All components of disease triangle required for disease to occur Disease Environment
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Screening nurseries under uniform conditions used to determine FHB resistance level Comparisons made with known checks DON also considered in evaluation
FHB Rating Disease Symptoms Rating for incidence and severity 18-21 days after first inoculation Incidence is percent of infected spikes in 1-mrow plot Severity is percent of infected spikelets on individual spikes FHB Index = Incidence*Severity/100
Choosing a MR variety is the only management tool I need to control FHB A. True B. False
What does a rating of MR mean? 2010 FHB INDEX SCALE FOR SPRING WHEAT COOP TESTS R <9.0 MR 9.1-20.0 I 20.1-30.0 MS 30.1-45.0 S >45.1 Resistance alone is not sufficient.
Disease Triangle Influences Management Strategy All components of disease triangle required for disease to occur Disease Environment
Fungicides Consider FHB risk forecast Suppressive do not provide complete control Timing of application critical (flowering) Application technology Configuration of sprayer nozzles to ensure proper application Best results when combined with more resistant varieties
Fungicide Efficacy with Cultivar (High Disease Pressure) Fungicide Glenn (MR-I) Roblin (S) FHB Index FDK DON FHB Index FDK DON Prosaro 93.6 55.6 73.1 12.3-4.3-20.4 Proline 97.9 67.5 69.9 21.9 11.3 13.6 Folicur 90.2 51.0 64.3 22.8-2.4 23.6 Caramba 95.7 57.9 70.3 6.8-6.8 10.0 Amarasinghe 2011 % reduction in FHB index, FDK and DON highest with more resistant cultivar Prosaro = tebuconozole + prothioconazole; Proline = prothioconazole; Folicur = tebuconozole; Caramba = metconazole (all triazoles)
Interaction Between Variety and Fungicide Treatment Four site-years Treatments FHB Inoculate untreated FHB Inoculated + Seed Fungicide (Crusier Maxx Cereals) FHB Inoculated + Foliar Fungicide (Prosaro 250EC ) FHB Inoculated + Seed + Foliar Fungicide Uninoculated untreated Varieties Spring Carberry (MR), Harvest (S) Winter - Emerson (R), CDC Falcon (S)
Effect on DON 30 a a a a 25 20 a a b b DON (ppm) 15 10 b b b b a ab b b 5 0 c c c c Carberry(MR) Harvest (S) Emerson (R) CDC-Falcon (S)
6 Effect on Yield 5 c Yield (t/ha) 4 3 2 a a b c b b b a a c a b b b a ab bc c d 1 0 Carberry (MR) Harvest (S) Emerson (R) CDC-Falcon (S)
Other Management Strategies Seed quality (Seedling blight vs Head blight) Crop rotation away from cereals and grasses Residue management promote rapid decomposition of residues Harvest management and storage combine settings and moisture content
Seed Quality Fusarium infected seed does not directly lead to FHB (Gilbert et al, 2003) Seedling blight and head blight are not the same FHB infected seed will affect seedling vigour, plant stands, and crop uniformity Recommendation to use healthy seed where possible (regulations differ between provinces)
Crop Rotation F. graminearum survives saprophytically on crop residues Corn, small grain cereals such as wheat and barley Avoid corn-wheat, wheat-wheat, barleywheat rotations Rotate wheat with non-susceptible crops Length of rotation depends on rate of decomposition of crop residues
Residue Management Tillage burying FHB infested crop residues reduces inoculum Burning Chop crop residues in smaller pieces so they degrade faster Remove crop residues Ascospores can travel large distances Good local practices may not be enough under conditions that favour the disease
Harvest Management Allowable FDK ranges from 0.25% to 4% by weight depending on class and grade Increased fan speed and shutter opening could reduce FDK (Salgado et al 2011, 2014) If infection is not uniform harvest areas separately Make sure grain is dry in storage Note: FDK and DON are not always highly correlated.
Summary FHB management is complex Variety resistance is not complete Fungicides are suppressive only Pay attention to environmental conditions at critical times Resistance plus other management practices are essential
Acknowledgements People Dilantha Fernando Jeannie Gilbert Brian Beres Mary Meleshko Eppie Austria Roger Larios Maria Stoimenova Chami Amarasinghe Zesong Ye Numerous summer students Funding WGRF NSERC Husky Energy CWB ARDI ACIDF AAFC