Cascade Hops Quality and Consistency from field to brewery. Thomas H. Shellhammer and David Gent

Cascade Hops Quality and Consistency from field to brewery Thomas H. Shellhammer and David Gent

Elements of this talk History of the Cascade hop Characterizing the flavor of Cascade hopped beer Recent developments on susceptibility to powdery mildew

Cascade History 1932 Oregon is the largest hop growing region in the world, 35,000 acres -mostly Cluster 1933 Prohibition ends Downy mildew discovered in Oregon hop yards U.S. Department of Agriculture establishes hop breeding program with the specific goal of developing downy mildew resistant varieties

Cascade History 1955 Stan Brooks USDA hop breeder Breeding for aroma varieties with noble hop characteristics adapted to the western U.S. USDA 56013 derived from an open pollination ( chance ) cross of a female derived from Fuggle and the Russian variety Serebrianka First harvest off 1 acre plots in 1967

Cascade History 1972 Cascade is officially released for commercial production Adolph Coors is the first brewer to begin using Cascade as a replacement for Hallertau Mittelfreuh

Identifying the odor impact compounds in beer dryhopped with Cascade hops

Mt. Hood Maturity Study (Probasco) 10 Alpha Acids (%) 7.5 5 2.5 Total Oil Alpha Acids (%) 0-30 -22.5-15 -7.5 0 7.5 15 Days Pre-/Post-Harvest

Mt. Hood Maturity Study (Probasco) 9 Alpha Acids (%) 6.8 4.5 2.3 0-30 -22.5-15 -7.5 0 7.5 15 Days Pre-/Post-Harvest Cone Appearance and Completeness Total Oil Alpha Acids (%)

Harvest Timeline OSU Maturity Study (Sharp, Townsend, Shellhammer) Harvest Dates by Farm and Year Early Typical Late Cascade Willamette 8/18 8/18 8/18 8/18 8/18 8/19 8/22 8/26 8/26 8/28 8/31 8/31 9/2 9/2 9/4 9/6 9/7 9/8 9/8 9/9 9/9 9/11 9/11 9/16

Harvest Timeline OSU Maturity Study (Sharp, Townsend, Shellhammer) Harvest Dates by Farm and Year Early Typical Late Willamette 7 days 4 days Cascade 8 days 6 days 8 days 8/18 8/18 8/18 8/18 8/18 8/19 8/22 8/26 8/26 8/28 8/31 8/31 9/2 9/2 9/4 9/6 9/7 9/8 9/8 9/9 9/9 9/11 9/11 9/16

Traditional Brewing Quality Parameters H.S.I. 0.27 Cascade Willamette Alpha Acids 9.0 Cascade Willamette 0.20 6.8 H.S.I. 0.14 % α-acids 4.5 0.07 2.3 0.00 Early Typical Late Harvest Point 0.0 Early Typical Late Harvest Point

Total Essential Oil 2.60 Cascade Willamette Essential Oil (ml/100g) 1.95 1.30 0.65 0.00 Early Typical l Late Harvest Point

Cascade Essential Oil 2010 Farm I 2011 Farm I 2010 Farm II 2011 Farm II 2.60 Essential Oil (ml/100g) 1.95 1.30 0.65 0.00 Early Typical Late Harvest Point

Cascade Essential Oil 2011 Farm I 2011 Farm II 2.60 Essential Oil (ml/100g) 1.95 1.30 0.65 0.00 Early Typical Late Harvest Point

Cascade Essential Oil 2010 Farm I 2010 Farm II 2.60 Essential Oil (ml/100g) 1.95 1.30 0.65 0.00 Early Typical Late Harvest Point

Preliminary brewing: Cascade Typical harvest hops = apple, apricot/peach, and sweaty/onion/garlic notes. Late harvest hops = higher melon and floral notes.

Hop oil contribution to Cascade aroma Hydrocarbons Monoterpenes Myrcene Sequiterpenes Caryophyllene, Farnesene Oxygenated compounds Terpene alcohols Linalool, Geraniol Sequiterpene alcohols Humulenol Epoxides Humulene epoxide Other Carphoyphyllene oxide Hops Sulphur compounds Thioesters Sulfides Other

Cascade Hop Oil Profile (0.7 1.4 ml/100g) 0.80 Concentration (ml/100g hops) 0.60 0.40 0.20 0.00 Myrcene Farnesene G. Acetate Epoxide Caryophyllene Oxide

Cascade Hop Oil Profile: Minor components have a big impact 0.030 0.023 Concentration (ml /100g hops) 0.015 0.008 0.000 G. Acetate Humulene Epoxide Beta Pinene Caryophyllene Oxide Limonene

Centennial Hop Oil Profile (1.5 2.3 ml/100g) 0.80 Concentration (ml/100g hops) 0.60 0.40 0.20 0.00 Myrcene Farnesene G. Acetate Epoxide Caryophyllene Oxide

Willamette Hop Oil Profile (1.0-1.5 ml/100g) 0.80 Concentration (ml/100g hops) 0.60 0.40 0.20 0.00 Myrcene Farnesene G. Acetate Epoxide Caryophyllene Oxide

Mt. Hood Profile

Mt. Hood Hop Oil Profile (1.2 1.7 ml/100g) 0.80 Concentration (ml/100g hops) 0.60 0.40 0.20 0.00 Myrcene Farnesene G. Acetate Epoxide Caryophyllene Oxide

Beer Production & Dry Hop Protocol Iso-Hopped Pale Ale 98% Great Western 2-row; 2% Acidulated Malt 20 ppm iso-alpha acids Wyeast Ale 1056 (removed for dry hopping) Post dry hop beer was transferred through cartridge filter into purged, clean vessel Dry Hopping: 12 L aliquots in stainless kegs for dry hopping 3.8 g/l (~1 lb/barrel) for 24 hours Foil pouch opened and hops were added under CO 2 Beer Temperature: 15.5 C Hop Preparation: Synthetic cheese cloth bags Bags were prepared in advance of dry hopping and stored cold in foil pouches, purged with N 2 State Harvested Kiln Alpha (%) Total Oil B-Pinene Myrcene Linalool Caryo. Farne. Washington 09/03/13 Propane 6.2 1.2 0.87 56.49 0.48 6.01 6.25

Liquid Extraction of Dry-Hopped Beer Liquid-Liquid Extraction 350 ml beer ρ = approx 1.00 g/cm 3 150 ml dichloromethane ρ = 1.33 g/cm 3 Organic layer used in S.A.F.E. Apparatus Beer Layer for SAFE extraction DCM

Solvent Assisted Flavor Evaporation (S.A.F.E) Based on a method outlined by Engel et. al 1 Procedure completed on CONTROL and Cascade MID oil content beer 1. Engel, W., Bahr, W., and Schieberle, P. Solvent assisted flavour evaporation - a new and versatile technique for the careful and direct isolation of aroma compounds from complex food matrices. Eur. Food Res. Technol. (online). 10.1007/ s002170050486, 1999.

Kuderna-Danish Evaporation & Concentration Extract dried with Na 2 SO 4 Concentrated to 4 ml under N 2

Aroma Extract Dilution Analysis (A.E.D.A) Collaboration with New Belgium Brewing Co. Grant Ruehle & Dana Sedin Principle: Analyze S.A.F.E Extracts with GC-Olfactometry Step 1: Geometric dilutions of extract prepared according to a method by Schieberle 2 Step 2: Odors acknowledged when they arise using software Step 3: Each dilution is sniffed in duplicate and identified using GC-MS 2. Gaonkar, A. G., and Schieberle, P. New Developments in Methods for Analysis of Volatile Flavor Compounds and their Precursors. In: Characterization of Food: Emerging Methods. Elsevier. 1995.

What is the goal of AEDA? Survey the compounds that are signature of Cascade dry-hop flavor 1:4 1:16 1:64 1:256 1:1024 1:2 1:8 1:32 1:128 1:512

Aroma Extract Dilution Analysis (A.E.D.A) Day 1 Original Extract Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Aroma Extract Dilution Analysis (A.E.D.A) Day 1 1:4 Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Aroma Extract Dilution Analysis (A.E.D.A) Day 1 1:16 Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Aroma Extract Dilution Analysis (A.E.D.A) Day 1 1:64 Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Aroma Extract Dilution Analysis (A.E.D.A) Day 1 1:256 Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Aroma Extract Dilution Analysis (A.E.D.A) Day 1 1:1024 Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Acknowledging an Aroma Event Mark the descriptors Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Acknowledging an Aroma Event Mark the intensity Day 1 Original 1:4 1:16 1:64 1:256 1:1024 Day 2 Extract 1:2 1:8 1:32 1:128 1:512

Matching aroma descriptors to chemical compounds Understanding what compounds are signature of Cascade dry-hop flavor Myrcene; FD = 32 Aroma Descriptors: Resinous Herbal Fruity Citrus Dilution # 1 2 3 4 5 6 7 8 9 10 Dilution Level 1:2 1:4 1:8 1:16 1:32 1:64 1:128 1:256 1:512 1:1024

Matching aroma descriptors to chemical compounds Understanding what compounds are signature of Cascade dry-hop flavor Aroma Descriptors: Floral Fruity Roasted Linalool; FD = 1024 Dilution # 1 2 3 4 5 6 7 8 9 10 Dilution Level 1:2 1:4 1:8 1:16 1:32 1:64 1:128 1:256 1:512 1:1024

Results Aroma Extract Dilution Analysis Control & Dry-Hopped Beer RT Description CONTROL FD - Eval 1 FD - Eval 2 7.22 unk 0 1 9.36 candy, caramel 0 1 Description DH Beer FD - Eval 1 FD - Eval 2 9.79 cereal, grainy, plastic 0 4 10.82 solvent 1 0 11.15 unk 0 1 11.27 fruity, apple, solvent 2 1 floral, solvent 2 0 11.99 Fruity, light struck, sulfur 2 0 12.25 13.15 cheesy, cooked, rancid, roasted, nutty, cereal 64 64 apple, banana, solvent, fruity 32 Cheesy, rancid, nutty, griany, roasted 64 8 candy, fruty, floral, estery, apple 4 256 13.66 cheesy, nutty 2 cheesy, rancid 0 8 13.71 rancid, cheesy, plastic 1 8 candy, fruity, tropical, 14.76 ester, anise 8 128 candy, floral, fruity, estery 16 256 15.72 light struck, sulfur, vegetable, cheesy 32 256 light struck, cheesy, resinous, sulfur 64 256 15.90 cheesy, nutty, roasted 2 8 grainy, cheesy, resinous 0 2 16.06 cheesy 1 0 16.85 fruity, apple 1 8 floral, fruity 2 4 17.50 sulfur, plastic, burnt 2 8 vegetable, sulfur, earthy 4 64 17.65 candy, fruity, sweet, estery, banana 16 64 18.30 solvent, estery, fruity 0 2 candy, fruity, banana, solvent 16 32 18.56 floral, fruity 2 2 fruity, plastic, solvent 4 32 nutty, caramel, ceral, dog 18.87 food 0 16 dogfood, grainy, nutty 16 256 19.38 buttery, popcorn, grainy 32 4 popcorn, buttery, nutty 8 16 20.15 unk 0 1 20.30 sulfur, tropical 8 4 20.89 apple 0 4 fruity, apple, ester 0 8 21.03 herbal, grainy, vegetable 2 0 21.15 herbal 4 0 21.33 grassy 1 1 herbal, earthy 1 2 vegetable, cabbage, 21.53 roasted, caramel, candy 2 16 sulfur, vegetable, earthy 16 64 21.67 herbal 2 0 21.88 resinous, herbal, fruity, 16 32 22.04 apple, estery, fruity 0 128 fruity, apple, estery 16 64 fruity, solvent, citrys, 22.16 resinous 1024 1024 fruity, solvent, citrus 512 1024 23.03 unk 0 1 22.62 fruity, sweet 1 0 23.12 caramel, roasted 2 0 23.62 fruity, caramel, grainy, 4 0 candy, caramel, grainy, caramel, bready, nutty, 23.91 bready, floral, rose 2048 64 roasted, rose 32 1024 23.94 rose 0 128 24.16 bready, cereal, nutty 1 0 roasted, caramel 2 0 24.46 candy, caramel, fruity 0 1 candy, roasted, tropical 0 1 24.84 earthy, fruity, solvent 0 8 vegetable, earthy, 2 2 25.07 earthy, fruity, solvent, 0 16 25.31 burnt, roasted 128 16 roasted, plastic 256 16 25.62 caramel, fruity, roasted 0 64 floral, fruity, roasted 2 1024 25.74 caramel 2 0 caramel, rose 2 0 25.89 roasted, caramel 2 0 26.04 cooked, caramel 0 1 caramel 0 1 26.15 rose, apple, fruity 2048 1024 rose 1024 1024 26.49 harsh, solvent, floral 0 2 27.69 plastic, chemical 1 2 cheesy 1 8 28.49 phenolic 1 0 29.00 citrus, phenolic 16 0 plastic, solvent, 29.23 chemical, caramel 0 4 plastic 0 16 29.69 herbal 32 0 herbal, floral 16 0 29.97 herbal 16 0 30.05 chemical, fruity, rose 0 8 rose 0 2 30.25 herbal, floral, rose 16 512 66 aroma events Unhopped Control Dry-Hopped Beer

Results Aroma Extract Dilution Analysis Dry-Hopped Beer 19 hop aroma events n o Odor Quality FD Factor 1 cereal, grainy, plastic 4 2 Fruity, light struck, sulfur 2 3 candy, fruity, floral, ester, 256 apple 4 rancid, cheesy, plastic 8 5 sulfur, tropical 8 6 herbal 4 7 resinous, herbal, fruity, citrus 32 8 caramel, roasted 2 9 fruity, caramel, grainy, nutty 4 10 rose 128 11 floral, fruity, roasted 1024 12 citrus, phenolic 16 13 herbal, floral, rose 512 14 rose, earthy 16 15 fruity, phenolic, roasted, 32 plastic 16 candy 2 17 fruity, banana 64 18 light struck, vegetable, sulfur 2 19 sulfur, light struck 64

Results Aroma Extract Dilution Analysis - Identification Retention Index NIST Library Flavornet Database n o Compound Odor Quality RI- DB5 FD Factor 1 unknown cereal, grainy, plastic 4 2 unknown Fruity, light struck, sulfur 2 3 2-methyl-1-butanol candy, fruity, floral, ester, 715 256 apple 4 isobutyl acetate rancid, cheesy, plastic 776 8 5 4-mercapto-4-methyl-2- sulfur, tropical 917 8 pentanonee 6 unknown herbal 972 4 7 myrcene resinous, herbal, fruity, citrus 993 32 8 unknown caramel, roasted 1029 2 9 b -phellandrene fruity, caramel, grainy, nutty 1053 4 10 2-phenylacetaldehyde rose 1081 128 11 linalool floral, fruity, roasted 1100 1024 12 unknown citrus, phenolic 1213 16 13 citronellol herbal, floral, rose 1230 512 14 2-phenylethyl acetate rose, earthy 1262 16 15 unknown fruity, phenolic, roasted, 1333 32 plastic 16 unknown candy 1349 2 17 b-damascenone fruity, banana 1386 64 18 unknown light struck, vegetable, sulfur 2 19 unknown sulfur, light struck 64

Results Aroma Extract Dilution Analysis Sorted based on FD no Compound Odor Quality RI- DB5 FD Factor 11 linalool floral, fruity, roasted 1100 1024 13 citronellol herbal, floral, rose 1230 512 3 2-methyl-1-butanol candy, fruity, floral, ester, 715 256 10 2-phenylacetaldehyde rose 1081 128 17 b-damascenone fruity, banana 1386 64 19 unknown sulfur, light struck 64 7 myrcene resinous, herbal, fruity, citrus 993 32 15 unknown fruity, phenolic, roasted, 1333 32 12 unknown plastic citrus, phenolic 1213 16 14 2-phenylethyl acetate rose, earthy 1262 16 4 isobutyl acetate rancid, cheesy, plastic 776 8 5 4-mercapto-4-methyl-2- sulfur, tropical 917 8 1 pentanone unknown cereal, grainy, plastic 4 6 unknown herbal 972 4 9 beta-phellandrene fruity, caramel, grainy, nutty 1053 4 2 unknown Fruity, light struck, sulfur 2 8 unknown caramel, roasted 1029 2 16 unknown candy 1349 2 18 unknown light struck, vegetable, sulfur 2

Results Aroma Extract Dilution Analysis Unknowns no Compound Odor Quality RI- DB5 FD Factor 11 linalool floral, fruity, roasted 1100 1024 13 citronellol herbal, floral, rose 1230 512 3 2-methyl-1-butanol candy, fruity, floral, ester, 715 256 10 2-phenylacetaldehyde rose 1081 128 17 b-damascenone fruity, banana 1386 64 19 unknown sulfur, light struck 64 7 myrcene resinous, herbal, fruity, citrus 993 32 15 unknown fruity, phenolic, roasted, 1333 32 12 unknown plastic citrus, phenolic 1213 16 14 2-phenylethyl acetate rose, earthy 1262 16 4 isobutyl acetate rancid, cheesy, plastic 776 8 5 4-mercapto-4-methyl-2- sulfur, tropical 917 8 1 pentanonee unknown cereal, grainy, plastic 4 6 unknown herbal 972 4 9 b -phellandrene fruity, caramel, grainy, nutty 1053 4 2 unknown Fruity, light struck, sulfur 2 8 unknown caramel, roasted 1029 2 16 unknown candy 1349 2 18 unknown light struck, vegetable, sulfur 2

Sulfur Compounds and Cascade (4-mercapto-4-methyl-2-pentanone; 4MMP) As described by Toru Kishimoto Muscat/blackcurrant-like characteristic Low concentration & HIGH flavor impact As described by Robert McGorrin cat-ketone Present in Sauvignon Blanc wines Detection: Requires highly sensitive instrumentation Unique method of detection with GC-MS

Cascade Hop Oil Profile (0.7 1.4 ml/100g) 0.80 Concentration (ml/100g hops) 0.60 0.40 0.20 0.00 Myrcene Farnesene G. Acetate Epoxide Caryophyllene Oxide

Cascade Hop Oil Profile: Minor components have a big impact 0.030 0.023 Concentration (ml /100g hops) 0.015 0.008 0.000 G. Acetate Humulene Epoxide Beta Pinene Caryophyllene Oxide Limonene

Next Steps Quantify target compounds in beer/extract Understand role in the context of the flavor threshold ID with pure chemical compounds Confirm identification using pure compounds Use of more sensitive instrumentation Reduce the number of unknowns in the analysis More replications next year 2015 project Repeat the work on Cascade DH beer confirm the findings

Ongoing Support from the Brewers Association Replicate work from 2014 using Cascade Centennial & Chinook dry-hop beer AEDA analysis Mixing study based on knowledge of impact compounds

Powdery Mildew and its Potential Impact on Cascade David Gent US Department of Agriculture

W. Mahaffee

Stage IV Stage V

Cone Color and Dry Matter

Cone Color and Dry Matter Cone color begins to deteriorate at about 25% dry matter in certain varieties

Cone Color and Dry Matter

Dry Matter and Cone Color are Correlated with Yield

9 Cone color (1-10 scale) 6.75 4.5 2.25 Oil content Cone Quality and Maturity Potentially competing objectives with later harvest 0 30 Cone color 16 19.6667 23.3333 27 Percent dry matter Increase in oil content, but also increasing potential for powdery mildew occurrence and damage Percent cones with powdery mildew 22.5 15 7.5 Not known precisely how this will influence flavor characteristics with dry hopping 0 16 17.8 19.7 21.5 23.3 25.2 27 Percent dry matter

Cascade and Powdery Mildew In the Pacific Northwest, historically Cascade has not been appreciably affected by powdery mildew Disease resistance appears to be due to a high level of quantitative resistance (ie, not a single gene that confers immunity)

Powdery Mildew on Cascade Reports of powdery mildew Cascade made increasingly since 2012 Studies launched in 2013 with support from Brewer s Association & WHC to understand scope and nature of outbreaks

2014 Outbreaks Increasing severity of outbreaks in yards that are true-to-type Cascade and increasing frequency of fungicide use

Cascade Is there a Cascade-adapted strain, or was 2014 simply a bad mildew year? Magnum Apollo

Evidence Indicates a Cascade- Adapted Strain Mildew from Cascade has a measurably greater aggressiveness on Cascade Shorter generation time (4-8% longer) More colonies per leaf (6-13X) More spores produced (100 to 1000X mores)

2015 and Beyond? Based on experience with other aggressive strains of the fungus that have overcome resistance, the expectation is Cascade-adapted strains will: Survive Increase in frequency in population Generally, will lead to earlier and more severe disease in field Need to be managed

Supply Stability and Quality Difficult to know, but several outcomes seem likely: Number of fungicide applications will increase Crop damage will become increasingly visible to customers Harvest timing will be earlier in some instances to mitigate crop damage How will these factors influence brewing quality?

THANK YOU Oregon State University

Brewers Association Hop Research Council Washington Hop Commission Washington State Commission on Pesticide Registration Western Region IPM Center David Gent USDA-ARS Corvallis, Oregon gentd@onid.orst.edu 541-738-4167

What is the Basis of Powdery Mildew Resistance in Cascade? Serebria nka +Fuggle +Fuggle Serebrianka is reported to possess R4 progeny 19124 If Cascade possess R4, strains of powdery mildew fungus capable of overcoming R4 should infect Cascade Casca de

Genetic Basis of Powdery Mildew Resistance in Cascade Expected Reaction with Actual Isolate Virulence R4 Reaction HPM-198 Vb, V3, V4, V6 + + HPM-199 Vb, V3 - + HPM-200 Vb, V1, V3 - + HPM-202 Vb, V3, V4, V6 + + HPM-203 Vb - + HPM-204 Vb, V1, V2, V3, V5 - + HPM-205 V4, V6 + +

Virule nce in fungu in fungu s s Resistance Factor in Host Rb Rb R1 R1 R2 R3 R4 R5 R6 Vb, V3, V5 V5 Disease Immune Immune Disease Immune Disease Immune Vb, V3, V5, + V4, V6 Race Characterization Disease Immune Immune Disease Disease Disease Disease 31 V6 isolates, 11 non-v6 (to date). Only 3 derived from Cascade: all race Vb,V3,V5)

Ability to Grow on Cascade is Widespread in Population 100 Percent of isolates virulent on Cascade 80 60 40 20 0 No disease Disease 60 isolates collected during 2012 and 2013

The Majority of Powdery Mildew Isolates from Cascade Lack R6-virulence 100 Percent of isolates virulent on Nugget 80 60 40 20 0 Disease No disease 2/41 isolates collected from Cascade during 2012, 2013, & 2014

Spray Timing & Yield Effects 100 Alpha yield (% of attainable yield) 75 50 25 20% of yield potential is dependent on disease control during late July to early August 0 0 18 35 53 70 Days of fungicide protection after bloom

Late Season Management Stage I Stage II Stage III Stage IV Stage V Mid July Late July Mid Aug Late Aug Early-Mid Sept

Resistance in Plants Qualitative or Major Gene Resistance Based on a single gene that gives full immunity Rb R1 R2 R3 R4 R5 R6

Quantitative Minor Gene (ex. Fuggle) Based on multiple genes Tolerance to the pathogen Generally more durable when deployed Qualitative Major Gene (ex. Nugget) Based on single R gene Complete immunity to the pathogen Less durable when deployed VERSES Picture from Poland et al. 2008

Increase in R6 acreage

R6 Cultivars Millennium Mt. Hood Nugget Super Galena Delta Triple Perle Apollo Bravo Crystal Summit Newport

Brief History 2011: Powdery mildew observed on a cultivar with R6-based resistance 2012: Fairly widespread outbreaks documented on several cultivars with R6 in Washington; observed in multiple hop yards in Idaho late-season 2013: First outbreaks confirmed in a limited number of yards in Oregon; increasing prevalence of R6-virulent strains of the fungus on cultivars lacking R6 in Washington 2014: Serious outbreaks of powdery mildew in Oregon; widespread occurrence of R6-virulent strains on cultivars lacking R6 in Oregon

When single R genes fail Major gene resistance is usually less stable than minor gene resistance The fungus only needs to overcome one gene to infect V6 R6 Infection V6 R2 Resistance

Single Gene Based Resistance Vir ule nce in fun gus Resistance Factor in Host Rb R1 R2 R3 R4 R5 R6 Vb Disease Immune Immune Immune Immune Immune Immune V1 Disease Immune Immune Immune Immune Immune V2 Disease Immune Immune Immune Immune V3 Disease Immune Immune Immune V4 Disease Immune Immune V5 Disease Immune V6 Disease

Race Typing Common virulence factors R genes still effective Vb V3 V5 11 isolates tested in 2013 to 2014 R1 R2 R4 R6 Emerging virulence factors Vb V3 V4 V5 V6 31 isolates tested in 2013 to 2014 Known R genes still effective R1 R2

Race Typing of Mildew Strains Viru lenc e in fun gus Rb R1 Resistance Factor in Host R2 Yeoman Zenith Target Challenger Sere- Early Choice Nugget Vb,V3,V5 Disease Immune Immune Disease Immune Disease Immune Vb,V3,V5 + V4, V6 R3 R4 R5 R6 Disease Immune Immune Disease Disease Disease Disease

2013 Powdery Mildew on Cascade Incidence of powdery mildew on Cascade was associated with yards planted from common rootstock

2014 Powdery Mildew on Cascade Incidence of powdery mildew greater than in 2013 Powdery mildew sprays increased from 1 to 3.5 in WA

Economic Impact of Harvest Timing (*w/ mildew) For a $5000 per acre CTZ crop, loss of $379 revenue for every 1% increase in dry matter beyond 25%