GRAPEGROWING A New Disease In Italian Pinot Grigio disease causes grapevine leaf mottling and deformation By Elisa Angelini, Irene Bazzo, Nadia Bertazzon, Luisa Filippin and Vally Forte

rapevine leaf mottling and deforma- tion are the hallmarks of a new vine disease spreading across - Ggrowing regions in northeast and . The first warning signs came in 2003-04, when symptoms were observed in the vineyards of Piana Rotaliana and Collio. During the next few years, the disease gradu- ally spread to every grapegrowing area in Tren- Alto Adige and Venezia Giulia—the two regions where it first developed. The disease then spread to neighboring regions such as , Emilia Romagna and . In Veneto, where it was first identi- fied in the DOCG area in 2013, it has become a constant presence, having been de- tected in each of the best grapegrowing prov- inces. In Emilia Romagna, there was a high incidence of infected plants in 2013, whereas in Lombardy the disease wasn’t detected until 2014. For the time being, the disease has only a sporadic presence in Emilia Romagna and Lombardy, which each have some hotbeds scat- tered throughout the region.

Clockwise from top right: The canes of affected vines are stunted with shorter internodes and smaller leaves; the cultivar displays nerve discoloration on its leaves until the end of the season; leaves show symptoms of deformation and discoloration.

56 &VINES September 2015 GRAPEGROWING

edges. There are, however, Glera are more evident at the start First article from Il Corriere Vinicolo some vineyards where symptomatic of the growing season, when they Editor’s note: This article is published as part of Wines & Vines plants appear randomly distributed can be confused with damage cooperative editorial effort with Il Corriere Vinicolo, the leading throughout the whole vineyard. caused by eriophyid mites and Italian industry publication (corrierevinicolo.com). Il Corri- thrips. At bud break, the infected ere Vinicolo is edited by Unione Italiana Vini, the largest Italian Symptoms and damage vines show a clear delay compared wine trade association. On a regular basis, our two publications to production to healthy plants, with stunted will share key articles in order to give readers a broader view of The symptoms described above for canes with short internodes bear- important wine in- , Gewürztraminer and ing small, deformed leaves with dustry topics in Italy and North America. 2014 n Vines without symptons n Vines with heavy symptoms The disease was detected for Cabernet seem to show few or no n Vines with moderate symptoms n Vines with extreme symptoms the first time in Pinot Gris, which symptoms at all. is where the Italian name for the Fortunately, the incidence of 100% disease comes from (malattia del Pinot Grigio disease in the affected Pinot Grigio or “Pinot Grigio dis- areas has remained generally low. 80% ease”), though it was later identi- In the vineyards observed in Tren- fied in other varieties. The tino Alto Adige, the average inci- cultivars most affected so far are dence in susceptible varieties was 60% Pinot Gris, , , said to be around 0.5% during the Gewürztraminer, Tocai Friulano past two or three years. In Friuli 40% and Glera (a grape used for Pro- Venezia Giulia and Veneto, the in-

secco production), all typical va- cidence might be lower. Symptom- (%) Production 20% rieties in the regions where the atic plants are present sporadically disease is most widespread. No and in an isolated manner in most data is currently available on the vineyards. However, when the inci- 0 susceptibility of other varieties dence of disease is higher, there is Vineyard 1 Vineyard 2 common to Italy and other Euro- generally a distribution in groups, Comparing the weight of in symptomatic and apparently healthy pean regions, although and localized both in the center and at Pinot Grigio vines at harvest. Game Changer.Changer.

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September 2015 WINES&VINES 57 GRAPEGROWING

discolored nerves and mottling on the leaf sur- growing season to the extent that no cane is The Glera grape, on the other hand, shows less face, which remains during vegetative growth. able to lignify. serious production losses, with an average of The symptoms often diminish as the grow- As for production, in some cases there is a about 35%, according to data gathered in ing season progresses, giving the impression desiccation of the inflorescence and bunch 2014. From the point of view of quality, symp- that the plants are recovering. In fact, the new shatter. Bunches of symptomatic plants are tomatic vines are prone to higher acidity, while canes and leaves that develop after fruit set generally smaller at harvest, with millerandage the concentration of sugars does not seem to appear normal. The following year, however, and delayed ripening—especially on the worse- vary significantly between symptomatic and the symptoms go through the same stages as affected plants. The depressive effects of the non-symptomatic vines. described above, proving recovery is only disease on production parameters seem more illusory and temporary. In more serious serious for Pinot Gris, where the weight of Incidence of the disease in Veneto cases—especially for Gewürztraminer—cane grapes at harvest may be reduced up to 80% In 2014, a voluntary territorial-monitoring development remains limited throughout the on symptomatic plants (see “Harvest 2014”). network was set up in Veneto by research bod- ies (CRA-VIT and the University of ), the Regional Plant Health Service, producers’ as- sociations, and grapegrowers includ- ing both consultants and sellers. A single monitoring sheet and online database have been adopted by the Plant Health Service and distributed to technicians working in the Veneto region to collect data. About 290 vineyards were monitored—es- pecially the cultivars Glera and Pinot Gris—and the symptoms were observed for each indi- Direct Flow Filtration vidual vine (about 500-1,000 vines per vine- The gentle alternative to cross flow yard). Only 29% of the vineyards observed had no symptomatic plants. Of the total vineyards • Extremely low transmembrane pressure. with symptoms, most currently show a very Less stress means better quality low incidence of the disease (less than 1%). In about 10% of the vineyards, the presence of • Minimal product loss symptomatic vines ranges from 1% to 10%. In • Low energy consumption nine vineyards (3% of the total), the incidence • Suitable for still or of symptomatic plants is higher than 10%, reaching peaks of 40% (see “Presence of Symp- • Automated process control by Diemme’s tomatic Vines”). InteliFlex software Processing data collected through the • Uses 30” code 7 cartridges monitoring sheet has shown no correlation between vineyard age and the presence of symptomatic vines. High levels of the disease

PRESENCE OF SYMPTOMATIC VINES

Incidence >10% Incidence 1%-10%

No Symptoms

Incidence < 1%

The presence of symptomatic vines in the vine- ColloPack Solutions • Napa CA • 707.258.3940 • www.collopack.com yards monitored in Veneto in 2014. The data have been organized into four classes of incidence.

58 WINES&VINES September 2015 091402 ColloPack DiemmeAd_4C_4.5x7.5_final_v2.indd 1 9/25/14 5:03 PM WinVineDripLok AD.qxp_Layout 1 12/1/14 2:52 PM GRAPEGROWING

KEY POINTS that highlight the presence of several strains of the virus, which are probably associated with Researchers from the CRA-VIT ( a different pathogenicity in the field. Research Center) in found These results lead us to believe that the that 71% of the 290 vineyards studied relationship between the virus and the disease in the Veneto wine region are affected is still unclear, and there is probably interaction by Pinot Grigio disease. with the environment, cultivation methods and The disease is associated with a virus agronomic practices that can influence the and affects Gewurztraminer, Pinot Blanc, expression of symptoms. Only more in-depth Tocai Friuliano and other grapes—in addi- studies will be able to clarify the situation. tion to Pinot Gris/Grigio—in various parts of northeast Italy. How the disease is transmitted By now it seems clear that the spread of this Vine growth, flowering and yields are all disease is increasing in this territory, but we adversely affected by the disease, for which still don’t know how it spreads. Observations RIP OK there is no known vector at this time. D L ™ carried out in the different Italian regions sug- Quick and economical, this long-lasting gest it is spread by an animal vector. It also dripline holder can be installed in were found both in young vineyards (just two seems that the infection increases slowly in the years old) and vineyards planted more than individual vineyards, though there are cases seconds. The built-in saddle prevents 40 years ago. From the observations carried of sudden outbreaks. This trend seems com- water flow restriction. Available in 1/2” out, it seems that at the moment the disease mon in the three most-monitored regions so and 7/8” sizes. is more widespread in the hilly areas of the far (i.e., Alto Adige, Friuli Venezia Patent No. 4,615,140 Veneto region, where it was detected in 84% Giulia and Veneto). For your nearest dealer, contact: of the vineyards observed, compared to the Given the lack of scientific data, at the mo- plains, where symptoms were identified in ment there are no strategies for fighting the 49% of vineyards. disease other than monitoring symptomatic An interesting relationship has emerged, vines in the field and potentially uprooting comparing the nature of the soil and the inci- stunted plants. dence of symptoms in the vineyards being Toll-Free: 877-552-4828 monitored. Most of the vineyards with a high Conclusions GovtLiaison_Dir08909-464-1373 • Fax: 909-464-160311/29/07 2:00 PM Pag incidence of symptoms are found on clay soil, Several Italian and European research bodies while most vineyards cultivated on loose soils are studying this disease and the GPGV virus. do not present visible symptoms. However, Researchers are looking into the association these are preliminary data that need more in- between the disease and the virus: how it is depth study. transmitted, laboratory diagnostics, recovery TTB of symptomatic vines and the possible effects The etiologic agent of nutritional deficiencies. It is also important LABEL Although the exact etiology (cause or causes) to understand if agronomical or environmental of the disease is still unknown, in 2012 the factors cause the disease, and therefore if co- presence of a new virus called grapevine Pinot existence with this problem is possible, given APPROVALS Gris virus (GPGV) was observed in symptom- the large number of vines that are infected by Low per-label costs atic plants from Trentino Alto Adige. Following the virus but do not show symptoms. Gov’t. Liaison Negotiations or Footwork this finding, the virus was identified in the Knowledge of this disease is still very lim- Reasonable Hourly Rates Italian regions affected by the disease as well ited, mainly because it has only recently been as other European states (Slovenia, the Czech discovered. In order to deal with increasing Republic, Slovakia, France and Greece), though concern and find prompt solutions, it is es- TRADEMARK some of these have never reported any pres- sential to continue doing research, join forces ence of the disease. Recent data from the analy- and share results both between research bod- SEARCHES sis of vine samples collected in several ies and technicians and those operating in the As Low as $185 vine-growing countries show that the virus is grapegrowing and nursery sector. Your trade names or designs are searched more widespread than first believed, since it at the U.S. Patent Office to help establish has also been found in , Serbia, Mon- The authors of the article work for CRA-VIT (Viticulture valuable ownership tenegro, Bosnia, Macedonia, Ukraine, Roma- Research Center), located in northeast Italy. Since 1923, or avoid costly legal liability. Over 100 years’ total staff experience nia, Spain and Portugal. CRA-VIT has studied issues related to the grapevine handling every government liaison need However, the presence of this virus is not including ampelography, genetic improvement, breed- for industry. directly correlated to the presence of symp- ing, biology, physiology, protection, propagation, ecol- Phone or write for details. toms: GPGV is present in all the symptomatic ogy, agronomic (and more recently metabolomic and vines but also in a large number of susceptible transcriptomic) techniques. The grapevine pathology 200 N. Glebe Rd., Suite 321 vines without any symptoms of the disease. In group, led by Dr. Elisa Angelini, carries out research Arlington, Virginia 22203 particular, recent studies carried out in the mainly focused on diseases associated with viruses, Phone: (703) 524-8200 Fax: 525-8451 region (Trentino-Alto Adige, Veneto, phytoplasmas, bacteria and their vectors. The research TOLL-FREE 1-800-642-6564 ) show that the virus is looks into etiology, epidemiology, diagnosis and control Major Credit Cards Accepted www.trademarkinfo.com present in about 70%-80% of apparently of grapevine diseases, molecular characterization of Since 1957 healthy vines. There are, however, new data pathogens and grapevine defense mechanisms.

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