Grape Virus Update

John Duarte, President Duarte Nursery

What is going on? How much do we know? What should growers do?

What is going on? DNI has invested heavily in testing and

replanting increase blocks since 2012.

Our increase blocks are cleaner than ever. We are delivering the cleanest plants ever.

New viruses are emerging and several viruses are spreading.

More customers than ever are calling with virus problems.

What are clean plants?

Micro-propagated Rootstock

100% Containerized

New Facilities

Greenhouse Sanitation

After cleaning, benches and floors are treated with an oxidizing chlorine foam to kill any pathogens before the next crop comes in.

Callusing Water Testing

Water into sand and UV filters After filters

Callusing Air Testing

Air into callusing before UV lights Air after passing through UV lights

Testing A. Increase blocks B. inspection C. Replanting

Transparency A. Plant health Reporting B. Testing results

Traceability A. Source blocks, grafting, growing origins. B. Who else received the same materials.

Duarte Clean Plant Program:

Mother Block Testing Last 2 Years

Total Mother Vines

Total vines tested

Positive for LR or

RB

% pos of vines tested

Increase blocks, scion and rootstock

388,072 17,201 30 .17%

Non symptomatic Scion varieties

4,845 2 .06%

Rootstock blocks 135,740 6612 0 0

Transparency Variety Clone Ranch Block 2010 Protocol Custom Client Testing

Rouging Mother Blocks 252,332 scion

135,740 rootstock Red Blotch= 14 vines

Leafroll (types 3,4,7 & 9) = 20 vines

GVB= 3 vines

Buffer vines = 2,924 vines

Visually symptomatic= 288

Only QA scion and rootstock at DNI

Clean Mother Blocks

How much do we know?(1)

We know the virus pathogens. - Deep sequencing - New characterizations

We know the status of our source materials. - Problem vines come back positive - Clean vines come back clean

DNI facility only has QAd propagation wood.

Visual inspection corresponds with testing results

We dont know how some viruses spread. GVRBaV LRV1-n

We cant predict adjacency spread rates.

We cant quantify mosaic spread rates.

Replant site reinfection is becoming suspicious.

How much do we know?(2)

Slide from California Agriculture, 2008 by DA Golino

Red Blotch Infection In Chardonnay

4th Leaf Red Blotch Infection

4th Leaf Leafroll Infection

What should growers do? Insect suppression.

Have a replanting plan: Manage adjacency Fallow period of 12 18 months.

Test and inspect nursery source blocks.

Test and inspect nursery vines in fall and deliveries.

Rogue new plantings annually. Replant if less than 1-2% in a year. Rogue and plan for replant if over 5%

Insect Suppression

What does this mean?

Larger acreages removed for adjacency.

Longer fallow periods?

More individual vine removal and replanting.

Annual rogueing passes.

Shorter vineyard life?

GRAPE SUPPLY REDUCTION.

Strategies

Simple higher density vineyard design (VSP).

Plant for easier vine removal: Less wrapping of cordons Away from line stakes

Use higher production clones.

Use more vigorous rootstocks.

Use larger format more mature grapevines.

Emerging Industry Practice Ubervine, Magnum, Standard sales from Duarte

Nursery, Inc. 2012-2016

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2012 2013 2014 2015 2016

Reg %

Mag %

Uber %

Advanced Production

0

1

2

3

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Std 12" vine Ubervine 35" with 1/2 crop Ubervine 25" with full crop

2012

2013

2014

TPA

Larry Bettiga, Viticulture Farm Advisor, Cooperative Extension Monterey.

For 2016 Duarte Nursery has:

28.1 Million Certified Buds 1.5 Million 2010 Protocol Buds

Total 29.6 Million Buds

18 month old Ubervines

Grape Virus UpdateSlide Number 2What is going on?Slide Number 4Micro-propagated Rootstock100% ContainerizedNew FacilitiesGreenhouse SanitationCallusing Water TestingCallusing Air TestingDuarte Clean Plant Program:Slide Number 12TransparencyRouging Mother Blocks252,332 scion135,740 rootstockOnly QA scion and rootstock at DNISlide Number 16How much do we know?(1) Visual inspection corresponds with testing resultsHow much do we know?(2) Slide Number 20Slide Number 214th Leaf Red Blotch Infection4th Leaf Leafroll InfectionWhat should growers do?Slide Number 25What does this mean?StrategiesSlide Number 28Emerging Industry PracticeUbervine, Magnum, Standard sales from Duarte Nursery, Inc. 2012-2016Advanced ProductionSlide Number 31Slide Number 32Slide Number 33