Meeting of COST Actions FA1003 & FA0807

Phytoplasmas and viruses management in Grapevine Collections forGermplasm Conservation, Mobilization and Evaluation

8‐9 May 2012, SOFIA (BULGARIA)

La Notte P., Venerito P., Savino V., Martelli G.P.

Centro Ricerca e Sperimentazione in Agricoltura “Basile Caramia”

Istituto di Virologia VegetaleCNR Sezione di Bari

Management of grapevine gene-banksand prevention from virus infections

The risk of virus infection and the control measures to keep unmodified the sanitary status of plants in the experimental fields vary according with the type and value of the material to be retained/evaluated as well as the place of collection and the local climatic conditions

• varietal collections for different purposes (i.e. rare autochthonous germplasm)

• collection of accessions deriving from clonal selection programmes

• collection of parentals for breeding activities

• comparison/ evaluation plot for clones, varieties, new crosses and candidate new varieties

• primary sources /initial materials of certified clones

Depending on their frequency, distribution, harmfulness and epidemiology, among the

high number of viruses reported on grapevine only few represent a real risk for

the reinfection and the evaluation in the gene banks. They are those associated with the

three most dangerous diseases considered by the European legislation on certification

of grapevine propagation material

Infectious degeneration disease (Nepoviruses)

Leafroll disease Rugose wood disease

Fanleaf degeneration is transmitted by:

infected propagation material

nematode vectors

Nematode (“soil” mediated) transmission

Ordine: DorylaimidaFamiglia: Longidoridae

Molto diffuso in Italia

NematodeNematodevettore:vettore:

XiphinemaXiphinemaindexindex

Grapevine Grapevine fanleaffanleafvirus and virus and itsitsspecificspecific vectorvector

unknownBLMoV Blueberry leaf mottle virus

Xiphinema americanum, X. bricolensis, rivesi, californicum, targanense, intermedium

ToRSV Tomato ringspot virus

Xiphinema americanum, Longidorus diadecturus, L. elongatus

TRSV Tobacco ringspot virus

Xiphinema americanumPRMV Peach rosette mosaic virus

unknownTKGDefV Grapevine deformation virus

unknownTKGARSV Grapevine Anatolian ringspot virus

unknownDCLRV Cherry leafroll virus

unknownTUGTRSV Grapevine Tunisian ringspot virus

unknownBG, HU, SRGBLV Grapevine Bulgarian latent virus

Unknown (X. index ?)HU-CZ-CR-AUGCMV Grapevine chrome mosaic virus

Paralongidorus maximusDRpRSV Raspberry ringspot virus

Longidorus attenuatusD, YU, IL, TK, CATBRV Tomato blackring virus

Longidorus apulus (only on vegetables)ITAILV Artichoke Italian latent virus

D, IT, TK, PTSLRSV Strawberry latent ringspot virus

Xiphinema diversicaudatumEUArMV

Arabis mosaic virus

Xiphinema index, (X. italiae and X. vuittenezi ?)

EU, CaliforniaGFLV Grapevine fanleaf virus

16 viruses (11 Europe)

Transmission of leafroll and rugose wood bynot flying insects vectors

GLRaVGLRaV--1: 1: Helicoccus bohemicus,Phenacoccus acerisPhenacoccus acerisParthenolecanium corni, Parthenolecanium corni, Neopulvinaria Neopulvinaria innumerabilisinnumerabilis

GLRaVGLRaV--3: 3: Planococcus ficus, Pl. Planococcus ficus, Pl. citricitriPseudococcusPseudococcus longispinuslongispinus..Ps. affinis, PsPs. . calceolariaecalceolariae, , PsPs. viburni, . viburni, PsPs. . maritimusmaritimusPsPs comstockicomstocki, , PulvinariaPulvinariavitisvitis

GLRaVGLRaV--5: 5: PsPs. . longispinuslongispinus

GLRaVGLRaV--9. 9. PsPs. . longispinuslongispinus

GVA: GVA: Planococcus citri, Pl. ficus,Pl. ficus,Pseudococcus longispinus,Pseudococcus longispinus,Ps. affinis, Ps. Ps. affinis, Ps. comstockicomstockiNeopulvinariaNeopulvinaria innumerabilisinnumerabilis

GVB: GVB: Pl. ficus, PsPs. . longispinuslongispinusPsPs. . affinisaffinis, ,

Mealybugs and soft scales

Mealybugs are much more efficient than soft scale in vectoring grapevine viruses in open field

• can transmit and are mobile in all stages

• have a high number of generation x year

• due to their behavior are difficult to control

• the transmission is semipersistent and not very specific. It allows the spread of infection with low population levels as well as the survival of a limited number of adults (hidden under the bark) is able to renew severe infestations.

Once planted a new vineyard the grower has no instruments to repair the

possible damages caused by viruses

The control of virus infection is based on the

PREVENTION

Selection and preparation of primary sorces

Officialregistration of

clones

Pre-multiplicationin vivo or in vitro

MmultiplicationConservation forthe pre-

multiplication

CONTROLLIServizio Controllo Vivai

SanitationSanitation

ThermoterapyThermoterapy Meristem tip cultureMeristem tip culture

PREVENTIVE MEASURES TO BE IMPLEMENTED BEFORE THE ESTABLISHMENT OF A NEW EXPERIMENTAL

VINEYARD

• Use of soil free from nematodes vectors (and fungal root rot agents)

• Control of soil-borne vectors

• Use of propagation material (rootstock and scion) “healty” or controlled to avoid the introduction of new viruses for the area

Controls to carry out before planting• Presence of rootstock shoots (also along the

boundaries) of any preceding vineyard• Nematological analysis (only vector species)• mycological analysis (i.e. Armillaria mellea,

Rosellinia necatrix)

Chemical control of soil-borne vectors ?

Fumigation

Nematocides

LOW EFFICACY IN DEPTH, VERY HIGH COSTS, HIGH ENVIRONMENTAL IMPACT

ELIMINATION OF ALTERNATIVE HOST SPECIES

Fig Pistachio

Ficus carica (Fig)Pistacia vera (Pistachio)Ceratonia siliqua (Carob tree)Prunus domestica (European Plum)Citrus sp. (Citrus) Malus pumila (Apple)Olea europaea (Olive)Salix sp. (Willow)

Brassica oleracea Mill. (Broccoli)Capsicum frutescens L. (Pepper)Fragaria X ananassa (Strawberry)Solanum lycopersicum (Tomato)Solanum tuberosum (Potato)Petunia X hybrida (Petunia)Chenopodium amaranticolorSolanum nigrum

X. diversicaudatum: Apricot, Avocado, Black Currant, Blackberry, Carnation, Celery, Citrus, Juniper, Cucumber, Fig, Garden Raspberry, Nectarine, Okra, Peanut, Pear, Perennial Ryegrass, Petunia, Rose, Soybean, Strawberry, Tomato

Correct grubbing up and replanting of vineyard

• Use of systemic herbicides to kill the vines (optional)• Uproot the vines carefully removing and burning all the roots (with excavator and hand finishing)• 80-100 cm deep plowing• Land left for at least 3 years using vernine cover crops (cereals or fodder)• Summer plowings

- Correct choice of field location (possibly isolated and not placed under the slope of other vineyards)

- Leave a band edge at least of 10 m from other borderingvineyards infected with infectious degeneration and infested by nematode vectors

-Ensure the isolation of surface water from sourrounding vineyards (i.e. digging a ditch)

Isolation of premultiplication fields and mother plant blocks

AND AFTER PLANTING …..

- Use dedicated equipments or clean themcarefully from soil from other fields

Measures, instruments and facilities to prevent or control the reinfection /over-infection

- Avoid to introduce in the gene-banksmaterial infected by nepovirusestransmissible by nematodes

- Monitoring continuously the possible occurrence of new symptoms

- Avoid to overgraft the plants

The populations of mealybugs must be continuously and carefully monitored especially when favorable

climatic conditions occur

Finding very low infestation levels is difficult and therefore the infestation may go unnoticed for several years

• peeling away bark on trunks checking where the adults use to over-winter

• checking on the roots at the base of vine trunk

• using specific pheromone traps to attract (in surrounding vineyards up to 400 m) and capture the males (probably now the best system to determine low infestation rates)

Insecticide for chemical control

• dormant organophosphate insecticide (i.e. chlorpirifos)

• in-season application of oragophosphate or carbammate (i.e. methomyl)

• insect growth regulators i.e. buprofezin (Applaud)

• nicotinoid systemic insecticide (imidacloprid)

N° of application, time of treatment, distribution by drip irrigation (in open field) or foliar treatment (mainly on plant in pots)

Facilities

the surveillance should be very high especially for the mealybugsbut their control is cheaper and much more effective

Seed transmissionCan the seedling be infected after a cross when the parentals are infected ?

• None of the viruses associate with leafroll, rugosewood and fleck is reported to be seed-borne

• GFLV occurs in the pollen and the endosperm but there are conflicting reports on seed transmission. Seed transmission has been reported for most, butnot all, nepoviruses, and BLMoV and CLRV are efficiently transmitted by pollen

Usually the reinfection of new germplasm occurs in the evaluation plot for the common technique to

over-graft adult plants in order to accelerate the fruit set for the first selection

For several viruses the reproduction could be considered as an alternative procedure of sanitation

Evaluation plot for new candidate varieties

It’s strongly suggested to keep the original seedlings self-rooted in pots up to the end of the first evaluation results

Thanks for the attention