the stripe rust epidemic of 2011: why? and what next?
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The stripe rust epidemic of 2011: why? and what next?. Dr. Mary Burrows Montana State University Bozeman, MT. Why was stripe rust so bad this year?. Widespread fall infection Extended fall Deep, lengthy snow cover Favorable spring temperatures - PowerPoint PPT PresentationTRANSCRIPT
The stripe rust epidemic of 2011: why? and what next?
Dr. Mary BurrowsMontana State University Bozeman, MT
Why was stripe rust so bad this year?1. Widespread fall infection2. Extended fall3. Deep, lengthy snow cover4. Favorable spring temperatures5. Flooding created wet, humid conditions throughout
the year6. Even after day temps became hot, night temps were
favorable for infection (50-70F)7. A widely planted, susceptible variety (Genou)8. New strains9. April: alerts from Xianming Chen that stripe rust was
off to an ‘early start’ in WA
Fall infection by stripe rust, 2010
Fall 2010: Distribution of stripe rust
Reports of stripe rust in Montana 20 June, 2011
(Diagnostic lab samples)
Stripe rust spore cloud: 23 June, 2011 near Kremlin (Hill Co.)
Photo courtesy of Ryan McCormick
Degree day map, 9 May, 2011First reports from Ronan, Kalispell
Degree day map, 24 May, 2011Reports from Havre, Fort Benton, Great Falls
Mary: “Genou is what??? Send a sample”
June 1: “Dan/Jeannie (Pondera, Toole Co) – it’s coming your way”
June 10: Pondera Co’s 1st sample came into the office
Why didn’t the epidemic stop when it got hot?• Stripe rust disease progress is tied to
night time temperatures
Great Falls 1 May to 30 July
50 to 70°F
The rusts of wheat
Jim Berg, MSU
Stripe Stem Leaf
Yellow Black Red
Rust diseases are not mutually exclusive
Leaf rust, stem rust: ‘Puccinia pathway’
Stripe rust: gen’l WA or Canada
Normally, this is wheat
Great Falls area, 23 June, 2011WW Variety: Genou
Stripe Rust: variety resistance is very effective at reducing yield losses
Yellowstone
PromontoryJohnston & Grey, 2006
Susceptible varietyResistant variety
CDC Falcon Yellowstone
Stripe Rust: variety resistance is very effective at reducing yield losses
Yellowstone
PromontoryJohnston & Grey, 2006
Susceptible varietyResistant variety
Seedling infection vs. adults• Seedling infections are often not in ‘stripes’
– Yellow rust• Seedling infections tend to be strain – specific (single
genes) – easily overcome by the pathogen• Adult resistance is non-race specific, more durable• Seedling and adult plant responses can be different• HTAP resistance: High Temperature, Adult Plant
resistance – doesn’t kick in until after stem elongation (Feekes 4-9; Zadocks 30-39) and average night temperatures remain above 50 and day temps are between 77 and 86 F
Current classifications: Winter Wheat http://plantsciences.montana.edu/Crops/2011data/2011WinterWheatVarieties.pdf
Tables 3, 4, and 14
Tolerant Moderate SusceptibleJagalene Above BigSky
Jerry Hatcher CDC Buteo
Judee NuWest CDC Falcon
Ledger Rampart Genou
NuFrontier Rocky Morgan
Yellowstone Vanguard Neeley
Wahoo NuWest
NuSky
Pryor
Current classifications: Spring wheat http://plantsciences.montana.edu/Crops/2011data/2011WinterWheatVarieties.pdf
Pages 23 and 24
Tolerant Moderate SusceptibleBrennan Conan AP604CL
Bynum Corbin Hank
Choteau Hyalite
Freyr Jedd
Jenna Knudsen
Kelby McNeal
Reeder Mott
Vida Norris
Volt ONeal
Note: this needs to be updated with 2011 data
Xiangming Chen, WSU, 2010
Stripe rust would have caused 54% yield loss in WA without fungicide application in 2010 if all varieties were as susceptible as PS279
If all resistant cultivars were grown, 1% yield loss with no fungicide application
Yield of control Yield loss (%) Yield Inc. (%)Cultivar (bu/A) by stripe rust by fungicideAP700CL 116.76 -1.43 -1.41Madsen 110.12 1.06 1.07Chuckar 106.62 7.14 7.68Rod 104.87 -1.63 -1.61Stephens 102.07 12.34 14.08Brundage 96 98.37 11.36 12.82Westbred 528 97.44 9.95 11.05Bruehl 95.27 6.65 7.12Buchanan 93.32 -4.77 -4.56ORCF-102 90.04 12.22 13.92Masami 86.10 14.44 16.88Eltan 85.99 10.48 11.71ORCF-103 83.07 14.67 17.19Cashup 78.78 10.59 11.84Tubbs 06 78.75 23.03 29.93Eddy 71.37 22.87 29.65Xerpha 70.49 26.15 35.40Bauermeister 67.28 20.61 25.96Farnum 66.43 2.22 2.27Lambert 64.43 33.34 50.01Paladin 63.72 20.38 25.60Finley 61.70 5.04 5.31Declo 42.15 44.00 78.58PS 279 29.88 54.17 118.19Mean 81.88 14.79 21.61Mean (Excl. PS 279) 84.14 13.07 17.41
Resistant check
Susceptible check
Fungicides
Ron Muzzana, 2011
Strobilurins TriazolesMode of action FRAC group 11: QoI
(quinone outside) inhibitors (respiration); spore germination, penetration, and mycelial growth
FRAC group 3 : DMI (demethylation) inhibitors; biosynthesis of sterols in fungal cell membrane; spore penetration and mycelial growth
Residual 14-21 days of protection
14-21 days of protection
Resistance development
High (specific MOA) Medium
Mobility in plant Translaminar and systemic
High
Protection Protective only (kill germinating spores)
Protective and curative
Note: these are generalizations about fungicide classes
50556065707580859095
100
No fun
gicide
Tillerin
gBoo
t
Floweri
ng
No fun
gicide
Tillerin
gBoo
t
Floweri
ng
Yie
ld (b
u/a)
Big Sky (Susceptible)
Influence of fungicide application on two stripe-rust infected WW varieties
(Quilt, 14oz, Bozeman 2007; P < 0.001, LSD = 6.3)
Yellowstone (Resistant)
a
b bb
c c c c
On-farm/on-station fungicide trials: flag applications (sprayed 9-10 June, rated 7-8 July)
Disease severity (plot rating, avg % leaf area covered by active stripe rust
pustules)
Treatment Rate Active ingredient(s) Company Hill Co.(var. Genou)
Toole Co.(var. Genou)
Liberty Co. (var.
Genou)
Control 11.25 4.625 2.5
Headline 3 oz/A Pyraclostrobin BASF 3.75 0.375 0
Headline 6 oz/A Pyraclostrobin BASF 0.125 0 0
Quilt 7 oz/A Azoxystrobin + Propiconazole Syngenta 1.25 0 0
Quilt 14 oz/AAzoxystrobin + Propiconazole Syngenta 0 0 0
Stratego 4 oz/A Trifloxystrobin + Propiconazole Bayer 1.375 0.125 0
Stratego 8 oz/A Trifloxystrobin + Propiconazole Bayer 0 0 0
Quadris 4 oz/A Azoxystrobin Syngenta 1.25 0 0
Tilt 2 oz/A Propiconazole Syngenta 0 0 0
Sprayed too early for max SR
Stripe rust on WWBozeman, 2011 – Bynum (Resistant to stripe rust)
TreatmentYield (bu/A)
Disease (% flag leaf area
29 June)
Untreated control 25.8 8.2 a
Headline SC 3 oz/A 29.8 4.2 b
Headline SC 6 oz/A 29.5 2.9 bcd
Quilt Xcel 14 oz/A 34.2 1.6 ef
Quilt Xcel 7 oz/A 32.4 2.3 def
Stratego 8 oz/A 37.6 2.0 def
Stratego 4 oz/A 31.3 3.4 bc
Tilt 4 oz/A 28.7 2.4 cdef
Tilt 2 oz/A 23.8 1.8 ef
Quadris flowable 12 oz/A 31.6 1.5 f
Quadris flowable 6 oz/A 25.5 2.7 bcde
P-value >0.10 <0.001
Sprayed 5 June, Feekes 5, 2011
Bynum Winter Wheat: ResistantNo yield benefit to tillering or flag fungicide application
(Priaxor, Headline, Evito, Quilt Xcel, Twinline study, Bozeman, 2011)
Photo: M. Moffet
Stripe rust on SWBozeman, 2011 – Vida – MR to stripe rust
Product Rate Timing
Disease12 Aug (% flag)
Incidence12 Aug
(%)Yield (bu/A)
Control 23 70 81 bc
Stratego YLD + Wolverine
1.5 oz/A + 1.7 pt/A
Tillering 32 95 84 abc
Stratego YLD 3 oz/A Tillering 17 83 80 c
Stratego YLD 1 oz/A Flag 2 40 86 ab
Absolute 500 SC
3 oz/A Flag 0 0 87 a
Prosaro 421 SC
3 oz/A Flag 0 6 81 bc
Prosaro 421 SC
4 oz/A Flag 0 5 86 ab
Prosaro 421 SC
10.5 oz/A Flowering 0 5 85 abc
P = 0.11
Glume infection of stripe rust
‘Rescue’ spraying?
Remember your PHI!
Hunger and Jackson. Foliar fungicides and wheat production in Oklahoma. http://lubbock.tamu.edu/wheat/pdfs/osufoliarfunghandout04.pdf
Economic impact?• Montana growers spent ~$15 mil. on
fungicide• Fungicides saved growers ~$30 mil.• Yield losses cost growers ~$48 mil.• Not spraying resistant varieties saved
~$12 million
Source: estimates from a grower survey, October 2011 (Burrows)
What does ‘strain’ mean when talking about stripe rust?
• Stripe rust is characterized by the pathogenic reaction on a series of wheat lines called ‘differentials’
• Virulence patterns have changed
Stem rust differentials
New strains are more aggressiveMoon and Milus, 2011
“Even though there was more initial inoculum of isolate AR90-01 [‘old,’ PST-3], isolate AR03-33 [‘new,’ PST-78] caused significantly more disease around the transplants in the spring at both Fayetteville and Kibler”
New strains infect plants at higher temperaturesMilus, E. A., Seyran, E., and McNew, R. 2006. Aggressiveness of Puccinia striiformis f. sp.
tritici isolates in the south-central United States. Plant Dis. 90:847-852.
• At 54°F, old and new isolates had similar latent periods and spore germination percentages.
• However, at 64ºF, new isolates averaged 2 days less for latent period and double the spore germination compared with old isolates.
• Therefore, the new isolates are better adapted and, thus, more aggressive at warmer temperatures than the old isolates.
A number of new strains were characterized after a severe epidemic in 2000
Chen, X. M., Moore, M., Milus, E. A., Long, D. L., Line, R. F., Marshall, D., and Jackson, L. 2002. Wheat stripe rust epidemics and races of Puccinia striiformis f. sp. tritici in the United States in 2000. Plant Dis. 86:39-46.
Che
n, X
. M.,
Moo
re, M
., M
ilus,
E. A
., Lo
ng, D
. L.,
Line
, R. F
., M
arsh
all,
D.,
and
Jack
son,
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Whe
at s
tripe
rust
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dem
ics
and
race
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ritic
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nt D
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-46.
How do new
strains originate?
Aecia on barberry
Uredinia on Kentucky bluegrass
Pycnidia on barberry
Aecia on barberry Uredinia on wheat
Jin, Szabo and Carson, Plant Dis., 2010
What qualifies as excitement for a plant pathologist:
2010 Stripe rust strains (PSTv-#)
16,1414 38
14, 44
22,39
46
2011 Stripe rust strains (PSTv-#)Data updated 9 Dec, 2011
11
11
11,14 14
14
14
14,3714,37
37
17
So what do those numbers mean? Virulence on differential lines of wheat
Virulence on differential linesYear Strain 1-10 11-20 21-50 Other2010 PSTv-14 1, 2, 6, 7, 8, 9 17 27, 43, 44 Tr1, Exp2, Tye
PSTv-16 1, 2, 6, 7, 8, 9 17 26, 27, 43, 44 Exp2, Tye
PSTv-22 2
PSTv-38 2, 6, 7, 8, 9 26, 27, 44 Tr1, Exp2
PSTv-39 2, 6, 7, 8, 9 26 Tr1, Exp2
PSTv-45 2, 6, 7, 8, 9 26, 27, 43, 44 Tr1, Exp2
PSTv-46 2, 6, 7, 8, 9 17 26, 27, 43, 44 Tr1, Exp2
2011 PSTv-11 1, 2, 6, 7, 8, 9 17 27, 43, 44 Exp2, Tye
PSTv-14 1, 2, 6, 7, 8, 9 17 27, 43, 44 Tr1, Exp2, Tye
PSTv-17 1, 2, 6, 7, 8, 9 17 27, 43, 44 Sp, Exp2, Tye
PSTv-37 2, 6, 7, 8, 9 17 27, 43, 44 Tr1, Exp2
What’s next?• PSTv-4 and PSTv-17 are virulent against
differential line Sp (“Spalding Prolific, Yr-SP)• YrSP virulence is in low frequency worldwide• Last year Yr-SP virulent races were detected
in low frequency and in 2011 increased significantly
• PSTv-4 is currently in Washington, Oregon, Utah and Idaho (not MT); PSTv-17 is in MT
• Bottom line: races are changing very fast; variety reactions will change, also: Scout crops, recognize the reaction types and manage appropriately
Stripe Rust: variety resistance is very effective at reducing yield losses
Yellowstone
PromontoryJohnston & Grey, 2006
Susceptible varietyResistant variety
So, what about next year?• Dry fall!• Hot spots due to prevented planting; WW seeded
very early• Plant a resistant variety• Use a seed treatment• Fall fungicide is generally not economical• Plan on a full rate of fungicide when spraying weeds
at tillering (blends preferred) on susceptible varieties if the weather is favorable for disease development
• Although stripe rust got all the glory, a lot of yield losses were due to root and crown rots
• Community disease
Diagnostic lab: routine functions and agricultural biosecurity
• Process approximately 2000 samples/yr (~80% homeowner/horticulture)
• Free to you• 100% grant funded staff, supplies, travel
– Space and utilities provided by MSU• Sample submission is important• Good sample = good answer
Network Responsibilities• Data collection (detectors/diagnosticians)• Communications system• Information storage and management• Data analysis
• New events and analysis of new appearance• Pattern recognition• Unusual patterns of endemic problems
• GIS• Event propagation• Tracking
• Reporting and alerts• Link to State Departments of Ag and US regulatory • agencies
AcknowledgementsDai Ito, Matt Moffet, Zach Miller,Linnea SkoglundMSU County Extension Agents
USPEST.ORG
Which seed treatment to use?• Very little data, and results showing yield benefit may
not be solely due to stripe rust control• Whether any products will prevent overwintering is
unknown• Within-field overwinter inoculum may be lower, but
this is still an airborne disease• Plant disease management reports:
www.planthealthmanagement.org – search for Xianming Chen and stripe rust (PDMR 1: ST005; 1: ST006; 1: ST007)
Contro
l
Proline
480 S
C
Prosaro
421 S
CQuil
t
A1559
0C
Alto 10
0SL
Caramba
Twinline
Headli
ne 2.
09EC
Gem 50
0 SC
0
20
40
60
80
100
120
Yiel
d (b
u/A
)
Yield, stem rust fungicide trial2009, Bozeman
a
bcd cdbc bc
a
cdd
bcb
Yield, stem rust fungicide trial2011, Bozeman
Untrea
ted
Strateg
o YLD
Strateg
o YLD
Strateg
o YLD
Absolu
te 50
0 SC
Prosaro
421 S
C
Prosaro
421 S
C
Prosaro
421 S
C
Twinline
Headli
ne A
MP
Priaxo
r
Quilt X
cel
Folicu
rEvit
o
Strateg
o EC Tilt
Alto 10
0SL
Proline
480S
C
Caramba
0
10
20
30
40
50
60
70
Yiel
d (b
u/A
)
Compare sprayed and unsprayed plots
Control (no fungicide), 14 daa
Strobilurin fungicides, 14 daa
Headline
Gem 500 SC
Strobiliurin + Trizole, 14 daaQuilt
Quilt Xcel
Strobiliurin + Trizole, 14 daa
Prosaro
Twinline
Trizole fungicides, 14 daa
Alto
Proline
Caramba