Managing mealybugs as vectors of GLRaV

and New Virus Problems for Vineyard

Managers

Sustainable Ag Expo

Kent Daane, Christina Wistrom, Kai Blaisdel, John Hutchins,

Brian Hogg, Janice Chen, Brady Chavez, Ashfaq Sial,

Glenn Yokota, Monica Cooper, Rodrigo Almeida

Special thanks to Marc Fuchs & Deborah Golino for GRBaV

Vectors of Viral Pathogens in Vineyards Grape Red Blotch Virus Vectors Control options

Grapevine Leafroll Associated Viruses Vectors Control options

Dr. Keith Perry Cornell University

Ithaca, NY

Dr. Mysore Sudarshana USDA-ARS Davis, CA

Dr. Marc Fuchs Cornell University

Ithaca, NY

UC Davis, Napa, Mendocino Seminars Dr. Marc Fuchs (mf13@cornell.edu) Red blotch: Challenges and opportunities http://fpms.ucdavis.edu/ (Foundation Plant Service – UC Davis)

Fanleaf First description 1841

Graft transmission 1962

Virus recognition 1960

Vector transmission 1958

Diagnostic assays 1960

Koch’s postulates 1962

Red Blotch: Challenges and opportunities

Leafroll 1905

1935

1979

1984

1984

n/a

Red Blotch 2008

2012

2012

2013

2012

2013

Vectors of Viral Pathogens in Vineyards 1. GLRaV Factors that Impact Control a) mealybug and leafroll species b) facts about mealybug-leafroll epidemiology 2. GLRaV Control Programs a) mealybug insecticides: which are best b) vineyard/areawide resistance management 3. What do We Know about Red Blotch? a) biology and ecology b) spread (grafts and vectors)

Vectors of Viral Pathogens in Vineyards 1. GLRaV Factors that Impact Control a) mealybug and leafroll species b) facts about mealybug-leafroll epidemiology 2. GLRaV Control Programs a) mealybug insecticides: which are best b) vineyard/areawide resistance management 3. What do We Know about Red Blotch a) biology and ecology b) spread (grafts and vectors)

photo courtesy of Deborah Golino

Grape vine leafroll associate virus: We will discuss insecticides for control of the ‘epidemic’

leafroll scenario that growers were initially worried about.

photo courtesy of Deborah Golino

…and also the mysterious arrivals of GLD

•>700 plant viruses •ca. 70% have insect, mite, nematode or fungal vectors

Martelli 2000. Proc. ASEV

aphids

whiteflies

soft scales

GLRaV Insect Vectors

GLRaV Insect Vectors •>700 plant viruses •ca. 70% have insect, mite, nematode or fungal vectors •most GLRaVs are closterovirids, which are vectored by whiteflies, mealybugs, aphids and soft scale

Martelli 2000. Proc. ASEV

aphids

whiteflies

soft scales

GLRaV-3 Mealybug Vectors in California

Vine mealybug Citrus mealybug

Obscure mealybug Grape mealybug Longtailed mealybug

The native grape mealybug (Pseudococcus maritimus) is the prevalent species and the likely historical vector of GLRaV in

most of California

The invasive vine mealybug (Planococcus ficus) is now

present, but does not explain past GLRaV movement

Gill’s mealybug

Rosciglione and Gugerli, 1987, Engelbrecht and Kasdorf 1990, Golino et al. 2002, Charles et al. 2006, Tsai et al. 2011

Obscure mealybug

Key Transmission Facts – Acquisition •Crawlers acquired virus w/in 1 hr •Peak at 24 hr

Tsai, Almeida et al. Phytopath. (2008)

Key Transmission Facts – Inoculation •Crawlers inoculated virus w/in 1 hr •Peak at 24 hr

Tsai, Almeida et al. Phytopath. (2008)

Numbers and seasonal presence of dispersal stages (crawlers) may be most important

Jan Jul Nov Sept Aug Dec Feb Apr Mar Jun Oct May Jan

Obscure mealybug

Vine mealybug

Lecanium scale

Grape mealybug

Cottony vine scale

4-6 gen/yr in Central Coast

3 gen/yr

Which leafroll species do you have?

Sharma et al. PLos One. 2011

What may be key is that viruses do change Eight GLRaV-3 strains found (to date) in Napa

vineyards, with multiple stains in some vineyards.

GLRaV-3aGLRaV-3bGLRaV-3cGLRaV-3dGLRaV-3eGLRaV-3fGLRaV-3abGLRaV-3acGLRaV-3adGLRaV-3bcGLRaV-3bdGLRaV-3cdGLRaV-3abc

a

b c

d e

f

Sharma et al. PLos One. 2011

Vectors of Viral Pathogens in Vineyards 1. GLRaV Factors that Impact Control a) mealybug and leafroll species b) facts about mealybug-leafroll epidemiology 2. GLRaV Control Programs a) mealybug insecticides: which are best b) vineyard/areawide resistance management 3. What do We Know about Red Blotch a) biology and ecology b) spread (grafts and vectors)

2 3 0 1

0

20

40

60

80

100

“3” Severe damage / lost cluster “2” Partial damage “1” Minor damage “0” No damage

Rating system for fruit damage

Dam

age

(% c

ateg

ory)

Back in the day… chlorinated hydrocarbons (DDT), OPs (parathion) and carbamates (Lannate) were used for grape mealybug control In the 1990s, Chemical Industry and UC sought alternatives to in-season OPs and Carbamates

Spray Volume: 100 GPA; Air-blast Sprayer; label rate. Details in Daane et al. 2006. Calif. Agricul. 60(1): 31-38.

Vine mealybug (P. ficus) was the target pest; Del Rey, CA.

Admire Applaud

Lorsban (as a delayed-

dormant

Control 0

40

60

80

100

20

b a b b

Frui

t dam

age

(% c

ateg

ory)

Admire (Imidacloprid)

Applaud (buprofezin)

Lorsban (chlorpyrifos)

Control

b

a

b b

0

10

20

30

40

0

5

10

15

20

25

30

Buprofezin (Applaud)

Acetamiprid (Assail)

Clothianidin (Belay /Clutch)

Spirotetramet (Movento)

Control

b b

c

a a

Spray Volume: 100 GPA; Air-blast Sprayer; label rate (Applaud 12 oz per ac) Clutch & Movento on 21 June 2011, Applaud & Assail on 7 July 2011

Planococcus ficus, Lodi-Woodbridge wine grapes, Lodi, CA

Since the 1990s, there are many novel materials. Here, I focus on Movento, Admire, Applaud, Clutch, Assail, & Lorsban

Buprofezin Acetamiprid Clothianidin

Spirotetramet Control 0

20

40

60

80

100

Frui

t dam

age

(% c

ateg

ory)

Cabernet Sauvignon

(2008)

Grape MB & Red Blotch (?)

Grape MB & GLRaV-3

In a newly planted block, two treatments: insecticides vs control

Can we simply kill all mealybugs for GLRaV control?

Highw

ay 29

GLRaV weak source block

GLR

aV m

oder

ate

sour

ce b

lock

GLRaV strong source block

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Insecticide

Control 11911711511311110910710510310199979593918987858381797775737169676563615957555351494745434139373533312927252321191715131197531

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row “1” missing

Two annual applications of a combination

of either Applaud,

Admire, Clutch or Movento

2009

2010

2011

2011

2011

2011

2011

2011 GLRaV3b

GLRaV3a GLRaV3c GLRaV3d

2012

2012

Where did the GLRaV-infected vines appear?

Insecticides No insecticides

0

5

10

15

20

25

30

Buprofezin (Applaud)

Acetamiprid (Assail)

Clothianidin (Clutch)

Spirotetramet (Movento)

Control

b b

c

a a

Spray Volume: 100 GPA; Air-blast Sprayer; label rate (Applaud 12 oz per ac) Clutch & Movento on 21 June 2011, Applaud & Assail on 7 July 2011

Planococcus ficus, Lodi-Woodbridge wine grapes, Lodi, CA

Insect growth regulator Applaud (Buprofezin)

Neonicotenoids Admire (Imidacloprid) Clutch (Clothianidin) Assail (Acetamiprid)

OPs and Carbamates Lorsban (Chlorpyrifos)* Lannate (Methomyl)* Dimethoate* *Listing here materials still effective and still registered

Biosynthesis inhibitor Movento (Spirotetramet)

Novel materials Insect must feed Slower kill (1-7 days) Relatively low residual

In ‘clean’ block remove the

infected vines

Treat source blocks to lower

populations

Treat new blocks to kill dispersing

crawlers

What about Areawide Control of Mealybugs / GLRaV?

If source blocks can eventually be pulled…

Continue to remove infected

vines and treat for dispersing crawlers

What about Areawide Control of Mealybugs / GLRaV?

1) Pheromone traps 2) Areawide mating disruption 3) Insecticides as needed

Attempted Areawide Vine Mealybug Control

♂ VMB per trap: 0 1-10 11-20

21-50 51-100 >100

2011 2012

Can Mating Disruption be Used as a Preventative? Comparison of ‘hot spots’ using pheromone traps

Results for 1 of 3 sites, shows that further spread can be prevented, and that farmers must work together.

Comparison of traps in hotspots between years

Tota

l num

ber P

l. fic

us m

ales

/ tra

p

2011 2012

0

50

100

150

200

250

300

Numbers of Pl. ficus in traps with total >20 VMB in either year generally decreased between 2011 and 2012, except in two cases.

When proper treatments are not applied the population will increase and spread.

Increase Decrease No change

Insecticides for ‘high density’ vine mealybugs Mating disruption to prevent spread Rogue vines (up to 20% infestation)

Vectors of Viral Pathogens in Vineyards 1. GLRaV Factors that Impact Control a) mealybug and leafroll species b) facts about mealybug-leafroll epidemiology 2. GLRaV Control Programs a) mealybug insecticides: which are best b) vineyard/areawide resistance management 3. What do We Know about Red Blotch a) biology and ecology b) spread (grafts and vectors)

Discovery of Leafroll Disease • Description of “rougeau” in France (Ravaz and Roos,

1905; Pacottet, 1906) and ”rossore” in Italy (Arcangeli, 1907)

• Graft-transmission (Scheu, 1935)

• Association of a virus (Namba et al., 1979)

• Serologically distinct viruses associated with the disease (Gugerli et al., 1984; Rosciglione and Gugerli, 1986)

• Mealybug transmission (Rosciglione and Gugerli, 1987)

• Koch’s postulates have yet to be fulfilled

Maree et al. Frontiers in Microbiology 4:82 (2013)

Discovery of Red Blotch Disease

• First description in Napa Valley (Calvi, 2008)

• A new DNA virus sequence (Krenz et al., 2012)

• Diagnostic tools made available (Krenz et al., 2012; Al Rwahnih et al., 2012)

• High correlation between virus presence and diseased vines (Al Rwahnih et al. 2013)

• Graft transmissibility (Al Rwahnih et al. 2013)

• Koch’s postulates are being tested by Dr. Fuchs

Pinot noir

Cabernet franc

Chardonnay

Grape Red Blotch (that looks like GLRaV)

PCR Diagnosis – TEST, DON’T GUESS! •Any tissue

(Leaf, petiole, dormant canes, clusters) •Any time

Fall and winter

slower berry ripening w/ GRBaV lower Brix w/ GRBaV

Distribution of GRBaV-infected vines

Genome Structure of a Circular Viral DNA

Protein Function V1 coat protein V2 unknown (movement?) V3 unknown (movement?) C1 replicase C2 replicase C3 likely not expressed

GRBaV 3206 bp

V2

V1

V3

C1

C2

TAATATT AC

C3

Grapevine red blotch-associated virus (GRBaV)

GRBaV replicase groups most closely with viruses of the genus Mastrevirus

Grapevine red blotch-associated virus

Treehopper

Leafhopper

Leafhopper

Whitefly

GRBaV coat protein groups separately from the other four genera of the family Geminiviridae

Grapevine red blotch-associated virus

Dissemination • Propagation

• Grafting

• Anecdotal evidence suggests spread in certain

vineyards

• Virginia creeper leafhopper can transmit GRBaV from grapevine to grapevine in the greenhouse (Poojari et al., 2013)

Koch’s Postulates for GRBaV – Dr. Fuch’s Laboratory • Pathogen must be present in all cases of the disease • Pathogen isolated from diseased host & grown in pure culture • Pathogen must cause disease when inoculated into a healthy host • Pathogen must be re-isolated from the new host and shown to be

the same as the originally inoculated pathogen

http://fpms.ucdavis.edu/ (Foundation Plant Service – UC Davis)

• Red blotch is a recently recognized disease, associated/caused by a newly discovered DNA virus (two distinct genetic variants of GRBaV)

• Delayed fruit ripening, reduced Brix

• Microshoot tip culture is not efficient at curing

• GRBaV is graft-transmissible, and some GRBaV spread in vineyards over time has been recorded

• Virginia creeper leafhopper may transmit GRBaV

• Symptoms can be misleading. Test, don’t guess!

Red Blotch: What Do We Know?

1. Etiology • Reproduce symptoms

Grafting? Leafhopper transmission?

• Visualization of virus particles

2. Detection • Optimize PCR • Serological assays • Seasonal distribution in infected vines • Latency period for symptom development

Red Blotch: What Don’t We Know?

3. Ecology • Vector(s) • Transmission from grapevine to grapevine in

vineyards

Red Blotch: What Don’t We Know?

3. Ecology • Vector(s) • Transmission from grapevine to grapevine in

vineyards

Red Blotch: What Don’t We Know?

Currently mapping blocks with GRBaV and GLRaV and comparing infection patterns with insect presence and cultural practices

Healthy vines

GRBaV

3. Ecology • Vector(s) • Transmission from grapevine to grapevine in

vineyards

4. Interaction of GRBaV and other viruses • Synergistic/antagonistic/commensalistic

relationships?

5. Improve elimination therapy methodologies • Meristem culture • Embryogenic culture

Red Blotch: What Don’t We Know?

6. Effect of GRBaV on vine health • Comparative performance evaluation • Tolerant cultivars • Tolerant rootstocks

7. Management • Clean stocks

Red Blotch: What Don’t We Know?

Thank you, Questions? ‘GLRaV & MB’ Collaboration & Help:

Walter Bentley, Jocelyn Millar, Lucia Varela, Rhonda Smith, David Haviland and numerous cooperating vineyards and vineyard managers

Support:

Associate, ‘FAR’ & Sterling Insectaries, Foundation Plant Services, Suterra Inc.

Laboratory direction & help :

Tina Wistrom, John Hutchins, Monica Cooper, Glenn Yokota, Vaughn Walton, Korey Kasir, Kevin Welzel, Karen Sime, Marcos Botton, Betsy Boyd, and Raksha Malakar-Kuenen