Fusarium Head Blight of Wheat: Progress and Challenges Ruth Dill-Macky David Van Sanford – Erik De...
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Transcript of Fusarium Head Blight of Wheat: Progress and Challenges Ruth Dill-Macky David Van Sanford – Erik De...
Fusarium Head Blight of Wheat:Progress and Challenges
Ruth Dill-MackyDavid Van Sanford – Erik De Wolf – Pierce Paul
IWC2015 - Sydney Australia
Fusarium Head Blight
re-emerged in 1992
the most important disease to limit wheat production in the
United States
increasing important globally
Fusarium
the most prevalent toxin-producing fungi of the northern temperate
regions
Fusarium toxins are found on infested wheat throughout
America, Europe and Asia
• Fusarium graminearum and other species
• produce mycotoxins
• regulated and effect grain marketing
Hard Red WinterHard Red Spring White Soft Red Winter Durum
USA wheat production areas- shown by class -
1993-1996
yield losses
>2.3 billion USD
Hard Red WinterHard Red Spring White Soft Red Winter Durum
USA wheat production areas- shown by class -
1996 - DON
conversion of all white wheat to
feed
Hard Red WinterHard Red Spring White Soft Red Winter Durum
USA wheat production areas- shown by class -
chronic DON contamination
significant yield losses 1996-2003
USWBSI
Variety DevelopmentGene Discovery & Engineering Resistance
Fungicides Disease Forecasting Models
Pathogen BiologyFood Safety
collaborative research effort since 1997 - funding from USDA 24 states - and grant universities and USDA scientists
Probable causes of the increase in Fusarium Head Blight
reduced tillage practices
susceptible cultivars
expanded corn production
weather patterns
favoring FHB
J F M A M J J A S O N D0
20
40
60
80
100
120
140 '61-90 '93-96
Month
Pre
cip
itati
on
(m
m)
Precipitation PatternsRed River Valley, MN
Wheat and Barley Cultivars
several very popular wheat cultivars were
highly susceptible to FHB
these were not tested during their development
all malt barley cultivars were moderately
susceptible
Fusarium Head Blight
the increase of FHBhas been associated with increased corn
production
and
widespread adoption of reduced tillage
practices
Hard Red WinterHard Red Spring White Soft Red Winter Durum
USA wheat production areas- shown by class -
since 2013
irrigated wheat in rotation with corn
FHB Pathogenspredominance of Fusarium graminearum (Gibberella zeae) as the causal fungus
F. culmorum, F. poae, F. avenaceum, F. equiseti, F. acuminatum, F. sporotrichioides, and others
Fusarium Head Blight
Sporadic epidemics reported in the United States since wheat
production was first established
From a historical perspective FHB was most effectively controlled
from the end of WWII to the mid-1980’s
- the era of the moldboard plow -
PROGRESS
HOST RESISTANCE
Phenotyping
Inoculated Mist-Irrigated Nurseries
Evaluation of FHB response:• Identifying susceptible varieties• Identifying sources of resistance• Screening breeding populations, elite
material and commercial cultivars• Identifying QTL associated with
reduced FHB and mycotoxins
Sources of Resistance
Evaluation of germplasm collections has identified resistance • Sumai 3, Frontana, Freedom, Abura,
16-52-9, Tokai 66
‘Native’ resistance has also been identified• Truman, Bess, Roane and others
Marker Assisted Selection
rr
RR
RR
Rr
S1
S2
S3
S4
Fun
oS
um
ai
3 CS
DT3
BL
N3
AT3
D N3
DT3
A BA
CR
1R
2R
3R
4
3AS CS3DS CS3BS CS, Sumai 3
3DS Sumai 3
Development of diagnostic markers for
Fhb1
Genotyping CentersThree Regional USDA Labs
Goals:• develop new molecular marker technologies• implement strategies for their application in
breeding• provide access to MAS technologies• maximize the efficiency of small grain
breeding programs
Traits:• quality and disease resistance
Marker Assisted Selection
Markers used for FHB resistanceName Locatio
nQTL Donor Marker
Qfhs.ndsu-3BS 3BS T. aestivum Xbarc133
Qfhs.ifa-5A 5AS T. aestivum Xgwm293
Qfhs.ndsu-3AS 3AS T. dicoccoides
Xgwm2
Qfsh.ndsu-2A 2AL T. aestivum XksuH16
Qfhs.ndsu-4BL 4BL T. aestivum Xwg909
Reaction of Wheat Varieties to FHB - 1996
Reaction of Wheat Varieties to FHB - 2014
Host Resistance – Best Practices
• avoid highly susceptible cultivars
• plant varieties with improved resistance
• diversify - spread in heading dates reduces risk
CHEMICAL CONTROL
Chemical Control
• Heading applications - 50-60% reductions in severity
- Early to mid 1990’s: mancozeb (protectant) and systemic MBC fungicides (benomyl)
- Late 1990’s: Tilt (propiconazole), Folicur (tebuconazole), Quadris (azoxystrobilurin)
- 2000’s: Caramba (metconazole), Proline (prothioconazole), Prosaro (prothioconazole & tebuconazole)
• Application technology - nozzle type & direction
Chemical Control
• Heading applications - 50-60% reductions in severity
- Early to mid 1990’s: mancozeb (protectant) and systemic MBC fungicides (benomyl)
- Late 1990’s: Tilt (propiconazole), Folicur (tebuconazole), Quadris (azoxystrobilurin)
- 2000’s: Caramba (metconazole), Proline (prothioconazole), Prosaro (prothioconazole & tebuconazole)
• Application technology - nozzle type & direction
associated with
increased DON
Fungicides – Best Timings
www.scabsmart.org
Fungicide Spray Angle and Direction
Chemical Control – Best Practices
• recommended fungicides Prosaro, Caramba and Proline – used with an adjuvant
• apply at early flowering (Feekes 10.51)
• application technology
Ground: twin directional nozzles – increase volume for best coverage
Air: use a small droplet size / evening or early morning (dew as additional water)
FHB Prediction Models
Opportunities:
• sporadic disease• plants vulnerable for short period of
time• environment impacts the disease cycle
Temperature
Precipitation
Relative humidity
Solar radiation
Wind
Wetnessduration
Inoculum production
Spore liberation
Sporedispersal
Sporedeposition
Host infection
Host colonization
Residue type Survival
Perithecia Conidiogenesis
Spore maturation
Ascopore release
Conidia release Inoculum level
Inoculum type Rain scrub
Aerodynamics Survival
Attachment Plant
architecture Survival
Host reaction Growth stage
Anthers
Spread within head Growth stage Other hosts
Erick DeWolf, Kansas State University
FHB Prediction Models
weather station
ScabSmart www.scabsmart.org
CULTURAL CONTROL
Residues are problematic as they harbor the initial inoculum from which epidemics
develop
increased corn acreage is likely the major driver of FHB in much of the world
conservation tillage has increased Fusarium survival in host & non-host residues
Fusarium Head Blight
in regions with extended winters
cold reduces microbial resulting in greater inoculum pressure
may also be true for regions with a dry
period
Residue Decomposition
Wheat residues support Fusarium as long as they are ‘recoverable’ - up to three cropping
seasons
Burying residues speeds residue decomposition BUT residues returned to the soil surface
support inoculum production
F. graminearum one of the earlier colonizers of residues - pathogenic phase may give it a competitive advantage as a saprophyte
Crop Residues
Wheat residues likely as good a host as corn
BUT corn residues persist longer
AND Bt-corn may exacerbate this
No-till vs reduced tillage
differences in residue-moisture interactions
Crop Residues
Regional, atmospheric spore populationsmore inoculum than within-field sources
(especially under FHB-conducive environments)
Within-field inoculumimportant in FHB-limiting environmentsbut generally less than 30% of the total
inoculum
Inoculum (debris) management strategiesin individual fields may help reduce FHB & DON
and contribute to integrated management
Host resistance - Fusarium survival
Resistance to FHB in wheat influences the colonization of residues (survival and
inoculum production)
FHB resistance can provide a benefits in future cropping seasons by reducing future inoculum
Avoiding the initial colonization of crops is a better option than trying to reduce Fusarium
levels in residues
Cultural Control – Best Practices
Avoid growing wheat in proximity to cereal debris(follow non-host crops)
Residue management following epidemic years
Plant resistant cereals - reduce Fusarium in debris
What is the contribution of individual practices to the management of
FHB/DON?
Resistant CultivarsFungicides / Prediction Tools Cultural PracticesOther
no single answer for all environments and cropping systems
FHB MANAGEMENT REQUIRES AN INTEGRATED APPROACH
Very susceptible cultivars have been eliminated
Resistance has been improved – BUT immunity is unrealistic and is not alone sufficient to eliminate
risk
Chemical control is needed in the management of FHB
Improved application technologies and forecasting systems have improved our ability to use
fungicides
Future Challenges
Adoption of varieties with improved FHB resistance
Maintaining identity of resistance in some markets
Maintaining/improving resistance over the long term
Ever increasing corn acreage
Limited options for rotations in many production systems
Impact of climate change on Fusarium species
Acknowledgements
Co-Authors:David Van Sanford, University of KentuckyErick De Wolf, Kansas State UniversityPierce Paul, The Ohio State University
USWBSI ColleaguesGary Bergstrom, CornellMarcia McMullen, NDSU
University of MinnesotaJames AndersonRobert BuschDavid GarvinRoger JonesGary MuehlbauerAlbert Sims
University of MinnesotaSmall Grains PathologyMatthew CullerAmar ElakkadC. Kent EvansPravin GautamSilvia PereyraCarlos PerezBacilio SalasBeheshteh Zargaran