N American Grapevine Yellows - PA Wine Grape Growers Network

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N American Grapevine Yellows - PA Wine Grape Growers Network

North American Grapevine Yellows:

Knowns, unknowns and research objectives

Tony Wolf & Tremain Hatch

Winter 2012


North American Grapevine Yellows


Aborted fruit


Leaf sympoms


“Rubbery” shoots


“Rubbery” shoots


combination of these three

symptoms


Nomenclature of grapevine yellows

diseases

• North American grapevine yellows

• Flavescence dorée

• Bois noir

• Australian grapevine yellows

• Others as well……


Yellows diseases are caused by phytoplasmas

• Limited to phloem (food-conducting) tissues of

plant – some symptoms may reflect a blockage

of phloem sieve tubes

• Bacteria-like organisms; fairly small genome


Examples of “Yellows” diseases: wide host range, global distribution

Disease

common name

16S rDNA

group-subgroup

Named 'Candidatus

Phytoplasma' species

Aster yellows (AY) 16SrI 'Candidatus Phytoplasma asteris'

Western X-disease

Palm lethal yellowing

16SrIII-A

16SrIV-A

Elm yellows 16SrV-A 'Ca. Phytoplasma ulmi'

Flavescence dorée

16SrV-C

Clover proliferation 16SrVI-A 'Ca. Phytoplasma trifolii'

Apple proliferation 16SrX-A 'Ca. Phytoplasma mali'

Pear decline 16SrX-C 'Ca. Phytoplasma pyri'

European stone fruit Y 16SrX-F 'Ca. Phytoplasma prunorum'

Stolbur phytoplasma

16SrXII-A

Australian GY 16SrXII-B 'Ca. Phytoplasma australiense'


A brief history of North American Grapevine Yellows

• Leaf Curl and Berry Shrivel, „DeChaunac‟, New York

State (Uyemoto, 1975 Uyemoto et a., 1977)

• “FD-like symptoms” in „Riesling‟, New York State

(Pearson et al., 1985)

• Scaphoideus titanus abundant in New York State GY

vineyards, and these insects often show + reaction to

FD antibodies in ELISA (Maixner et al., 1993).

Yellows, or “North American Grapevine Yellows

reported in Virginia (Prince et al., 1993; Wolf et al.,

1994).


A brief history…. continued

Yellows, or “North American Grapevine Yellows

reported in Virginia (Prince et al., 1993; Wolf et al.,

1994):

– Initial findings related the Virginia phytoplasma to “Xdisease”

(16SrIII group)

– Subsequently (Prince et al., 1994), a second phytoplasma

was detected in the 16SrI group (Aster Yellows)

– Both phytoplasmas found in cultivated vines (e.g.,

Chardonnay) and in asymptomatic wild vines (Vitis spp.),

and the AY type was also detected in black cherry

(Prunus serotina)


A brief history…. continued

• NAGY sub-group findings (Davis et al., 1998)

– “X-disease” (16SrIII group) phytoplasma unique for

this taxonomic group and given “I” sub-group

classification

– “Aster yellows” (16SrI group) also unique, and given

“A” sub-group classification


A brief history….

fast-forward…

• Reassessment of NAGY

phytoplasmas from eastern US

vineyards (Davis et al. 2012)

confirmed only 2 phytoplasmas in

vineyards of VA, MD, PA and NY.

• As originally stated, these

phytoplasmas are not the cause of

the European yellows diseases

such as Flavescence dorée or Bois

noir

Dr. Robert Davis

USDA/ARS

Beltsville, MD


Overview of NAGY development


Phytoplasma-positive plants

Red and white clover

wild grapevine

dandelion

aster

American elm

sycamore

black cherry


Vectors of Other Phytoplasma Diseases

Leafhoppers

Planthoppers

Psyllids

www.cedarcreek.umn.edu


Identification of vectors

Dr. LeAnn Beanland

Virginia Tech

“Malaise trap”


Plant disease vectors found in samples

www.cedarcreek.umn.edu

*Scaphoideus titanus


Mean # S. titanus at

BRC

Predicted No. of S. titanus at

Brown

Mean # S. titanus

at GM

Seasonal increase of

Scaphoideus titanus

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

Forest

Vineyard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Collection Day

1

0.75

0.5

0.25

0

Forest

Vineyard

1 3 5 7 9 11

Collection Day

13

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

Forest

Vineyard

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Collection Day


Total # Scaphoideus titanus transect sticky

traps over a two-year period

3

4

2

5

3

2

31

66

94

122


Example of edge effect of NAGY incidence at a small vineyard near Flint

Hill, VA. Each black spot is an affected vine observed in one year (1997).

Pasture

Chardonnay (1.15 ha)

Riesling (1.17 ha)

Pasture

N

Sauvignon blanc (< 0.2 ha)

Pasture


Examples of leafhoppers (Scaphoideus titanus and Jikradia olitorius) that showed

a pronounced difference in yellow sticky trap captures between woodland and

vineyard locations.

Poles # 3,4,7,8

Trap location on

pole

S. titanus

J.

olitorius

Vineyard Canopy (5’) 1 10

Vineyard Lower (8’) 1 1

Vineyard Middle (14’) 1 0

Vineyard Upper (20’) 0 0

Poles # 1,2,5,6

Woods Canopy (5’) 10 19

Woods Lower (8’) 12 60

Woods Middle (14’) 7 36

Woods Upper (20’) 9 19


Candidate Vector Species Captured in

Sweep Samples

Agallia constricta 2960

Polyamia weedi 336

Exitianus exitosus 334

Latalus sayi 311

Amblysellus curtisii 234

Deltocephalus flavicosta 189

Endria inimica 167

Sorhoanus orientalis 161

Chlorotettix galbanatus 122

Graminella nigrifrons 85

Paraphlepsius irroratus 64

Balclutha abdominalis 54

Macrosteles quadrilineatus 26

Doratura stylata 22

Jikradia olitorius 15

Osbornellus auronitens 13

Scaphytopius nigrifrons 12

Agalliopsis novella 8

Athysanus argentarius 8

Acertagallia sp. 4

Scaphoideus titanus 3

Aphrodes flavostrigatus 2

Colladonus clitellaris 2

Idiodonus kennicotti 1


4/2/2002

4/16/2002

4/30/2002

5/14/2002

5/28/2002

6/11/2002

6/25/2002

7/9/2002

7/23/2002

8/6/2002

8/20/2002

9/3/2002

9/17/2002

10/1/2002

10/15/2002

Mean # A. constricta

captured in the vineyard

4/2/2002

4/16/2002

4/30/2002

5/14/2002

5/28/2002

6/11/2002

6/25/2002

7/9/2002

7/23/2002

8/6/2002

8/20/2002

9/3/2002

9/17/2002

10/1/2002

10/15/2002

Mean # A. constricta

captured in scrub

Agallia constricta Captured in Sweep Samples

120

90

60

30

0

Date

120

90

60

30

0

Date


Species that have Tested Positive

(PCR) for Phytoplasmas

• Agallia constricta

• Balclutha abdominalis

• Latalus sayi

• Graminella nigrifrons

• Scaphytopius sp.

• Draeculacephala sp.

• Endria inimica

• Amblysellus curtisii

• Exitianus exitiosus

• Paraphlepsius irroratus

• Jikradia olitorius

• Deltocephalus flavicosta


Transmission Experiments

Required to show that insect is truly a vector


Insects Caged on GY-infected

Grapevine in the Vineyard


Rearing “Insect-free” Plants


Several positive transmission

vectors of NAGY

Agallia constricta Scaphoideus titanus Macrosteles spp.


Lespedeza sp.


Examples of non-Vitis plant hosts that were found to

harbor NAGY phytoplasmas

Species Common name + / total Phyto.

group

Prunus serotina Black cherry 1 / 9 AY

Platanus occidentalis Sycamore 1 / 2 X

Ulmus sp. Elm 1 / 3 AY

Trifolium pratense Red clover 2 / 2 1 AY, 1?

Trifolium repens White clover 2 / 2 1 AY, 1?

Lespedeza sp. Lespedeza 1 / 1 AY


What we know:

Grapevine yellows in Virginia is caused by at least 2

distinct phytoplasmas

‣ Multiple insect (leafhopper) vectors are involved

‣ These insects are typically more abundant outside the

vineyard than within

‣ Multiple alternative hosts are implicated

Grapevine varieties vary in susceptibility to NAGY

‣ Nurseries probably not a source of infected vines

(although this was recently of concern in Canada)


What we don’t know:

‣ Are all candidate vectors equally effective (or can we

target specific one(s)?

‣ Would persistent (e.g., soil-applied) insecticides

effectively reduce transmission rates?

‣ Multiple alternative hosts are implicated -- but which are

most common to “high incidence” vineyards? Is removal

truly effective in reducing phytoplasma reservoir?


What we don’t know (continued):

‣ What strategies can be used to suppress spread?

o Site selection

o Variety selection

o Removal of potential alternative hosts

‣ What tactics can be used to suppress spread?

o Insecticides

o Landscape management

o Removal of affect vine (or vine parts)


‣ Our work with NAGY has been dormant since 2006

‣ We just filled a position to explore some aspects of

NAGY, including:

o What are the common landscape features that

distinguish “high risk” vineyards

‣ What tactics can be used to suppress spread?

o Targeted insecticide applications

o Landscape and/or vineyard floor management

o Removal of affect vine (or vine parts)

‣ This will require a multi-year approach. Unfortunately,

there are no guarantees of “success” with this work


Thank you.

Questions?

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