Kutcher, H. Randy

English

University of Saskatchewan Research Archive

www.usask.caFusarium head blight of cereals: improving management of this difficult diseaseSoils and Crops Workshop, March 10th, 2020Randy Kutcher, Plant PathologistCrop Development Centre, University of Saskatchewanwww.usask.caWhat is Fusarium Head Blight (FHB)?• An infectious disease of cereals, corn, grasses and some other crops• Also called scab or tombstone on cereal grains• Occurs worldwide and from coast to coast in Canada2www.usask.ca• bleaching of the whole head or individual spikelets• may be salmon pink -orange spore masses on the spikelet and glumes.FHB symptoms, wheatA. Friskop, North Dakota State Universityhttps://www.ag.ndsu.edu/publications/crops/fusarium-head-blight-scab-of-small-grains3www.usask.ca• tombstone / scab• shrivelled, light-weight kernels, chalky white colour• the earlier during anthesisinfection occurs the greater the effectCanadian Grain Commissionwww.grainscanada.gc.ca4FHB symptoms, wheatwww.usask.ca• individual spikelets or whole heads affected• infected spikelets or kernels may be pink, orange or black• kernels shrunken and thin, often more difficult to identify in barley than in wheatCourtesy A. Tekauz5FHB symptoms, barleywww.usask.ca• Lack of highly resistant wheat cultivars• Presence of infected residue from previous crops• Intensive rotations (with increasing presence of corn) in western Canada• Weather favourable for infectionFHB – why the problem?6www.usask.caWhat causes Fusarium Head Blight (FHB)?• Caused by a number of Fusarium species that can also cause seed decay, seedling blight, and stem and root rot• F. graminearumF. avenaceumF. culmorumF. poaeF. sporotrichioides7www.usask.caDNA of Fusarium spp. (µg) per kg dry weight of wheat (Saskatchewan)64391633661 167 9602000400060008000DNA (µg/kg )Mean of 144 samples from growers’ crop samples, 2014-2016; G. Singhwww.usask.ca• 1923 - reported in Manitoba,• 1984 - localized outbreak in Red RiverValley, and under irrigation in Idaho,• 1993 - record rainfall associated with highF. graminearum in MB, ND & MN,observed in durum in SE SK,• 1996 - 3rd worst year in MB, SW MB aproblem area, F. graminearum foundat high levels in SE SK.History in Canadawww.usask.cablack soil zonedark brown soil zonebrown soil zoneLocation of F. graminearumon the Prairies   1985Canadian Grain Commissionwww.usask.cablack soil zonedark brown soil zonebrown soil zoneLocation of F. graminearumon the Prairies   1993Canadian Grain Commissionwww.usask.cablack soil zonedark brown soil zonebrown soil zoneLocation of F. graminearumon the Prairies   1999Canadian Grain Commissionwww.usask.caFusarium graminearum chemotypefrequencies in Canada,1984 to 2004 Ward et al.  2008www.usask.caChemotype frequencies of F. graminearum isolates collected from durum in Saskatchewan (2014 – 2016)89.29%10.71%1984 - 2004; n = 121 2014 - 2016; n = 178 71.30%28.65%www.usask.caFHB, yield and quality losses• Yield loss• 40-50% when severe• Grade loss• Mycotoxin contamination• Implications for animal & human health and end use market acceptability• These losses are additive!www.usask.caSaleability factors• Fusarium damaged kernels (FDK)• MycotoxinsCourtesy of G. Singhwww.usask.caFHB, yield and quality losses17Use FDA Advisory LevelHuman Consumption1 part per million (PPM) for finished grain products for human consumption. No standard for raw grain going into milling process.Cattle over 4 months old10 ppm (providing grain at that level doesn’t exceed 50 percent of diet).Poultry 10 ppm (providing grain at that level doesn’t exceed 50 percent of diet).Swine 5 ppm (not to exceed 20 percent of ration).All other animals5 ppm (providing grains don’t exceed 40 percent of diet).• DON (deoxynivalenol) aka ‘vomitoxin’ • In poultry, ingestion may stunt growth, poor feather development, • In cattle poor weight gain,• DON contaminated feed may result in feed refusal and vomiting in livestock, with pigs more sensitive than poultry or cattle• DON levels >30 parts per million (ppm) occurwww.usask.caFHB and swine productionDON-free RationRation with5 ppm DON18www.usask.caFusarium head blight (FHB) strategies• Cultural control – diverse rotations- managing infected residue• Fungicide management of the diseaseand appropriate use of fungicides- increased seeding rates• Genetically resistant varieties- clean seed and seed treatment- early seeding may avoid the disease• Integrated Pest Management imperativewww.usask.caFHB, genetic resistance• ‘Resistant’ cultivars, wheat• CWRS marketing class, many varieties are I (intermediate) or MR (moderately resistant), reduced spike symptoms, FDK, DON content• CWAD (durum) cultivars are S to MS • Better resistance means fewer FDK & less DON• Winter wheat may escape infection20www.usask.caFHB, genetic resistance2126https://publications.saskatchewan.ca/#/products/83696www.usask.ca• Escape• early maturity, staggered planting dates• subtle differences among varieties in length of flowering period,FHB, management strategies22www.usask.ca• infection occurs at anthesis(flowering) in cereals• flowering starts 2 to 3 days after spike emergence and lasts ~4 - 7 days• Infection occurs under warm (15-30oC), moist (rain, dew or high relative humidity) conditionsInfection in wheatwww.usask.caFungicide application timing: anthesisBBCH 59 BBCH 65 BBCH 69BBCH 61BBCH growth stage scale; Lancashire et al. 1991, Ann. Appl. Biol. 119: 561-601.http://www.saskwheatcommission.com/producer-info/fusarium-risk-assessment-map/www.usask.caFHB, chemical controlFungicide efficacy has been inconsistent, and only suppresses the symptoms, NOT control• perhaps due to the number of Fusarium species• application equipment (sprayer technology)• difficulty in timing applicationswww.usask.caFDK (%)AB051015202530High LowSeed rate effect on FDK and DONAB051015202530High LowDON (ppm)Saskatoon & Outlook 2016 LSD(0.05)www.usask.caFungicide timing effect on FDK AB BBCCAD0510152025FDK (%)LSD(0.05)Photo credits: G. Singh and Sprayers 101Saskatoon & Outlook 2016www.usask.caFungicide timing effect on DONABBBC BCAC0369121518DON (ppm)LSD(0.05)Photo credits: G. Singh and Sprayers 101Saskatoon & Outlook 2016www.usask.caFungicide products: efficacy of triazole fungicidesPaul et al. 2008tebuconazole propiconazole prothioconazole prothioconazole metconazole+ tebuconazoleProline® Prosaro® Caramba®www.usask.caExpt 1 Tr. 15 mph, Single, Conventional69% 31%Single vs double nozzles49% 51%Expt 1 Tr. 35 mph, Double, ConventionalCourtesy T. Wolf –33www.usask.caSpray pattern (quality) & boom height Single forward angled nozzleDeposit on simulated wheat headsDeposit volume (L/ha)025507510012515017520022525027512” Boom Height 18” Boom Height 30” Boom HeightFineMediumCoarseFineMediumCoarseFineMediumCoarseCourtesy T. Wolf – Sprayers 10135www.usask.caOther tools - Fusarium Risk Assessment Mapshttps://static1.squarespace.com/static/5c40f31a620b85cf0d073e7b/t/5cdc7d3f7817f743060d2fb1/1557953860589/Fusarium-Management-Guide.pdf32www.usask.caFungicide control of FHB depends on:• cultivar, • pathogen (Fusarium species, chemotype), • application timing,• the fungicide product and the rate of application• spray patterns, nozzles, nozzle angles, boom height Triazole fungicides applied at floweringcan provide suppression NOT control33www.usask.caFHB, control• Optimize combine settings• Inspect crop 18-21 days after flowering• Bleaching symptoms will be at peak and give an idea of what to expect at harvest• FDK are lighter weight than healthy seeds in wheat• High air speeds blow out some FDK34www.usask.caFHB, seed treatment• Effective against seedling blight, but little effect on epidemic development• seed cleaning and fungicide treatment usually does not improve quality enough for use as seed (germination and emergence)• Fusarium survives poorly on seed so germination may improve overwinter35www.usask.caSummary of FHB• The integrated approach is required and is economically beneficial and stable across environments,• Follow a diverse crop rotation (minimum of 3 crops) and use resistant cultivars (when available),• Timely fungicide application using appropriate application conditions (boom height, nozzle orientation, spray volumes), provides reasonable suppression,• Combining a diverse rotation with resistant cultivars and fungicide (when warranted) is more efficacious than any single approach.36www.usask.caAcknowledgementsAgriculture Development Fund www.usask.caThank you for the invitation to speak to you this afternoon

Fusarium head blight of cereals: improving management of this difficult disease

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Fusarium head blight of cereals: improving management of this difficult disease

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