Vine Research Articles

Virulence and cross-infection potential of Ilyonectria spp. to grapevine.

Black foot is an important disease of grapevines, affecting vines in nurseries as well as in young plantations. In recent years the disease has increased in incidence and severity throughout the world. Black foot is associated with at least two Campylocarpon and 12 Ilyonectria species, most of which have only recently been described. The recognition of previously unknown species, together with published reports of variability in virulence between and within species identified as I. macrodidyma and I. liriodendri , underlined the need to compare the virulence of isolates from these complexes. A further objective of this work was to determine the cross-infection potential of isolates of these species from other hosts to grapevine. Results from this study revealed recently described species such as I. lusitanica , I. estremocensis and I. europaea to be more virulent to grapevine than the species previously accepted as the main causal agents of black foot, such as I. liriodendri and I. macrodidyma . Furthermore, these results also provided support for isolates obtained from non-grapevine hosts to be as virulent to grapevines as isolates obtained from grapevine, underlying the cross-infection potential of these pathogens.

Partial defoliation improves must quality of cv. Albariño infected by Grapevine leafroll associated virus 3

The effect of leaf removal treatments around vine cluster zones on must quality were tested during 2003 and 2004 in Rias Baixas (Spain) in two Albarino vineyards infected by GLRaV-3. As expected, the main virus damage was decreased sugar content (2.1 Brix in 2003 and 0.9 Brix in 2004) in the musts compared with leafroll-free plants. Leaf removal improved must quality by decreasing titratable acidity by between 0.5 and 1.9 g L-1 of tartaric acid, depending on the experiment; it also increased the grape sugar content an average of 1 Brix. In vineyards with high incidence of GLRaV-3, partial defoliation at veraison, or 2 to 3 weeks later, had an improved must quality, counteracting the negative impact of the virus. This process is recommended to avoid penalties in wineries during years with poor ripening conditions.

Ecophysiological Traits May Explain the Abundance of Climbing Plant Species across the Light Gradient in a Temperate Rainforest

Climbing plants are a key component of rainforests, but mechanistic approaches to their distribution and abundance are scarce. In a southern temperate rainforest, we addressed whether the dominance of climbing plants across light environments is associated with the expression of ecophysiological traits. In mature forest and canopy gaps, we measured leaf size, specific leaf area, photosynthetic rate, and dark respiration in six of the most abundant woody vines. Mean values of traits and their phenotypic change (%) between mature forest and canopy gaps were predictor variables. Leaf size and specific leaf area were not significantly associated with climbing plant dominance. Variation in gas-exchange traits between mature forest and canopy gaps explained, at least partly, the dominance of climbers in this forest. A greater increase in photosynthetic rate and a lower increase in dark respiration rate when canopy openings occur were related to the success of climbing plant species. Dominant climbers showed a strategy of maximizing exploitation of resource availability but minimizing metabolic costs. Results may reflect phenotypic plasticity or genetic differentiation in ecophysiological traits between light environments. It is suggested that the dominant climbers in this temperate rainforest would be able to cope with forest clearings due to human activities.

Diversity of black Aspergilli and mycotoxin risks in grape, wine and dried vine fruits

Mycotoxin risk in the grape product chain is primarily due to ochratoxin A (OTA) occurrence in wine and dried vine fruits. Aspergillus carbonarius and the A. niger group are the main agents of Aspergillus bunch rot of grape, and they, especially A. carbonarius, are responsible for OTA contamination worldwide. Fumonisin B 2 (FB 2 ) represents an additional potential mycotoxin risk in the grape-wine product chain and A. niger / A. awamori were recently reported as the FB 2 producers in grapes. A deeper understanding of the species diversity of black Aspergilli, together with specific knowledge of their ecology and epidemiology, can help to predict their occurrence. From this perspective several studies have been done regarding prevention and control of black Aspergilli and reduction of mycotoxin risk at all stages, from vineyard management to wine-making procedures. In this review a comprehensive overview of all these aspects is presented.

GRAPEVINE NECROTIC UNION, A NEWLY RECOGNIZED DISEASE OF UNKNOWN ETIOLOGY IN GRAPEVINES GRAFTED ON 110 RICHTER ROOTSTOCK IN CALIFORNIA

In Northern California, surveys of several vineyards planted to Vitis vinifera cv. Pinot noir (PN) clones 02A, 667, 777, and UCD 04 grafted onto the rootstock V. berlandieri x V. rupestris 110 Richter (110R) revealed 2 to 45% of vines showing solid red leaf canopies and two distinct disease stages, i.e., full canopied plants with normal grape clusters (designated as acute) or stunted shoots and straggly bunches (designated as chronic). In addition, the scion-rootstock junction of symptomatic grapevines had developed a necrotic union; hence, the name ‘grapevine necrotic union’ (GNU). Also, two white fruited cultivars, Chardonnay (clone 04, vineyard in Yolo county) and Pinot gris (clone 152, vineyard in Monterey county), exhibited GNU-associated symptoms, with an exception of pale yellowed leaves. A detailed survey, from 2004 to 2009, was made in a sub-block containing 664 grapevines (8 rows x 80-85 grapevines) in a PN 02A vineyard (planted in 1997) located in Sonoma county. The initial incidence of GNU was 2.1% in 2004 and rose to 21.9% by 2009 suggesting secondary spread. Molecular assays (RT-PCR and PCR) for grapevine viruses, phytoplasmas, and Xylella fastidiosa, failed to detect a putative causal agent. Likewise, bud-chip inoculations of test plants of Cabernet sauvignon scions on different rootstocks, including 110R, were inconclusive. However, several bench-grafts of collections of PN 02A, PN 91 and Chardonnay 04 onto 110R produced plants that developed GNU symptoms in a research plot. Based on the results obtained so far, GNU is being regarded as an emerging disease of unknown etiology in California vineyards.

Stem characteristics and ant body size in a Costa Rican rain forest

Abstract:Climbing plants provide efficient pathways for ants to access patchy arboreal resources. However, plant stems vary greatly in physical characteristics that are likely to influence ant locomotion. We collected, measured and identified ants foraging on 671 stems of climbing plants at the La Selva Biological Station, Costa Rica. We applied tuna baits to 70% of the observed stems to attract ants to a broad range of stem sizes. We used these data to examine relationships between relative stem roughness, growth form (herbaceous or woody), stem diameter and the body length of foraging ants representing 58 species. The size of the largest ants found on stems generally increased with stem size up to 3.2 mm diameter, whereas the size of the smallest ants present on stems did not vary with stem diameter. The largest ants in the forest (Paraponera clavata) used small stems (<2.7 mm diameter) only when attracted by baits. Average (± SE) ant body length was larger on woody (5.2 ± 0.32 mm) vs. herbaceous (3.3 ± 0.53 mm) stems, but did not differ between rough and smooth stems within these categories. Ant body-size distribution tended toward unimodality on smooth stems. We conclude that small stem diameter acts as a habitat filter based on ant body size, but only for the largest ants in the forest. The filter effect is reduced when ants are attracted to an artificially high quality resource.

Wound healing property of aqueous extract of seed and outer layer of Momordica charantia L. on albino rats

Momordica charantia is a tropical vine bearing edible fruit which is among the most bitter of all vegetables. Several reports indicate that the extracts obtained from the fruits of M. charantia have significant wound healing activity and antidiabetic property. Aqueous extract is routinely used as traditional medicine to treat various ailments. In this report, the effect of aqueous extract of the seed and outer layer of the fruits of M. charantia on wound healing of albino rats is presented. Wounded albino rats treated with seed and outer layer extracts recovered faster than the untreated control animals. After 4 days, there was 20% reduction of the wound area on control animals while 45.75% and 47.5% reduction noticed on animals treated with seed and outer layer of the fruits of M. charantia , respectively. Further, animals treated with extracts showed significant increase in protein, hydroxyproline, hexosamine and uronic acid contents compared with respective controls. These data permit the observation that the extracts of M. charantia promote wound healing in animal model and indicated that the outer layer extract of M. charantia has potential use to treat different types of wounds in human beings too.

Percentage of fertility of gems and content of carbohydrates contained in roots, vine shoots and leaves from grape cultivar Itália

A cv. Italia e a principal representante das uvas finas de mesa com sementes no Vale do Submedio Sao Francisco, e, por ser uma cultivar introduzida na regiao, ajustes de manejo cultural tem sido necessarios para torna-la mais produtiva. Analises de teores de carboidratos em raizes, sarmentos e folhas da cv. Italia, enxertada sobre o porta-enxerto IAC-313 (‘Tropical’) foram realizadas e correlacionadas com as taxas de fertilidade de gemas de sarmentos situados em diferentes posicoes do braco primario das plantas. Verificou-se que a fertilidade de gemas varia de acordo com a posicao dos sarmentos nas plantas, havendo uma correlacao positiva entre a fertilidade potencial de gemas e os teores de amido e de acucares totais, e que a expressao da fertilidade de gemas em sarmentos situados na posicao basal da planta e maior.

Effect of partial defoliation on <i>Cylindrocarpon destructans</i> infection of grapevines

Oneyearold grapevines of Sauvignon blanc grafted to rootstocks 10114 or Schwarzmann were used to evaluate the effects of partial defoliation and inoculation with C destructans on disease severity incidence and dry weight accumulation Assessment 8 months after treatments showed that disease incidence was not affected by the defoliation treatments However disease severity was significantly highest for the highly defoliated plants (P0043) Incidence and severity were similar for Schwarzmann (293 and 84 respectively) and 10114 (310 and 149 respectively) Root dry weight was affected by the defoliation treatments (P0000) being significantly lower in the highly defoliated plants than the moderately defoliated and undefoliated plants (156 185 and 199 g respectively) The practice of leaf removal in young vines clearly needs to be managed when black foot is a recognised risk factor for newly planted vineyards

Proceedings of the 21st Annual UCLA Indo-European Conference. Los Angeles October 30th and 31st, 2009. Stephanie W. Jamison, H. Craig Melchert and Brent Vine (eds.), with the assistance of Angelo Mercado.

Proceedings of the 21st Annual UCLA Indo-European Conference. Los Angeles October 30th and 31st, 2009. Stephanie W. Jamison, H. Craig Melchert and Brent Vine (eds.), with the assistance of Angelo Mercado.

East and West. Papers in Indo-European Studies. Edited by Kazuhiko Yoshida and Brent Vine.

East and West. Papers in Indo-European Studies. Edited by Kazuhiko Yoshida and Brent Vine. Hempen Verlag Bremen, 2009. viii, 312 Seiten. Broschiert, 42,00 EUR. ISBN: 978-3-934106-70-3.

Studies on the effect of water and temperature stress on grapevines inoculated with Eutypa lata

Three independent studies were conducted in Australia and Spain to examine the effect of water and temperature stress on the development of Eutypa dieback of grapevines. In Adelaide, South Australia, ‘Red Grenache’ vines in pots were inoculated with Eutypa lata and subjected to various temperature and soil water regimes, then assessed for foliar symptoms, wood staining and colonization by the fungus. Vines subjected to a combination of heat or cold plus low or high soil moisture displayed more severe foliar symptoms, the most severe occurring on vines subjected to the hottest (30°C) and wettest (20–40 % soil water content) conditions. Wood staining was not related to foliar symptom severity or to the temperature and moisture combination. Furthermore, there was no relationship between staining and mycelial growth, indicating that staining may not be an accurate reflection of the spread of E. lata . In Cabrils, Spain, ‘Tempranillo’ vines were subjected to water stress in pots and showed a significant reduction in shoot diameter growth, stomatal conductance and leaf water potential. Inoculation with E. lata also decreased the leaf water potential of stressed vines. Wood staining in inoculated vines was similar irrespective of watering treatment. Further investigations are needed to elucidate the relationship between stress and growth of E. lata in infected vines. Field experiments in two climatically different regions (Barossa Valley and Riverland) of South Australia suggested that water-stressed vines in a warm, dry environment may be more susceptible to infection of pruning wounds by E. lata than vines receiving standard watering.

Influence of water stress on Botryosphaeriaceae disease expression in grapevines.

Several species in Botryosphaeriaceae have been associated with grapevine trunk diseases. To evaluate the effect of water stress on infection of grapevines by Botryosphaeriaceae spp., 1-year-old Shiraz/101-14 Mgt nursery grapevine plants were planted in plastic potting bags and placed outdoors under shade netting. Five weeks after planting, vines were pruned and the pruning wounds inoculated with spore suspensions of Neofusicoccum australe , Neofusicoccum parvum , Lasiodiplodia theobroma e or Diplodia seriata . Control treatments consisted of applications of sterile water or a Trichoderma harzianum spore suspension. Stem inoculations were done by inserting a colonised or uncolonised agar plug into a wound made in each stem. Four different irrigation regimes were introduced 12 weeks after planting to simulate varying degrees of water stress. Measurements of stomatal conductance, photosynthetic rate and leaf spectrometry were made to monitor physiological stress. Eight months after inoculation, vines were uprooted and the root, shoot and plant mass of each vine determined. Lesions observed in the inoculated pruning wounds and stems were also measured. Vines subjected to the lowest irrigation regime were significantly smaller than optimally irrigated vines. Water stressed vines also had significantly lower photosynthetic rates and levels of stomatal conductance compared with vines receiving optimal irrigation, indicating that these plants experienced significantly higher levels of physiological stress. The mean lesion length was significantly longer in the pruning wounds and stems of plants subjected to the lowest irrigation regime, with lesion length declining linearly with increasing irrigation volume. These results clearly indicate that when a grapevine is exposed to water stress, colonisation and disease expression by Botryosphaeriaceae spp. are much more severe.

First studies on the potential of a copper formulation for the control of leaf stripe disease within esca complex in grapevine.

An experimental formulation based on copper oxychloride and gluconates, which is able to penetrate vine foliar tissue, was tested for wood treatment against some of the fungi involved in the diseases included in the esca disease complex. In vitro trials were carried out to: i) test the effect of the formulationon the mycelial growth rate of Phaeomoniella chlamydospora (Pch), Phaeoacremonium aleophilum (Pal) and Fomitiporia mediterranea (Fmed), and on the conidial germination of Pch and Pal; and ii) conduct a preliminaryinvestigation of the presence of the copper formulation on the ability of Pal to produce toxic metabolites. Trials were also conducted on potted vines to i) measure copper penetration into the trunk of potted vines using atomic absorption spectrophotometry; and ii) test the effect of the copper formulation on colonization ofthe fungus in trunks. Finally, the copper formulation was field-tested in vineyards showing leaf stripe. The implications of the tests in the control of the esca disease complex are discussed.

Symptoms and fungi associated with esca in South African vineyards

In the past, only a few incidences of esca diseased grapevines were reported from the Slanghoekand Rawsonville areas of South Africa, with the damage believed to be of little importance so that the diseasehas not been studied in South Africa. In the present study, vines with internal or external symptoms of the esca disease complex were sampled from table, raisin and wine grape cultivars from 37 production areas inthe Western Cape, Northern Cape and Limpopo provinces of that country. Most vines were greater than 10years old, but younger vines (3 and 5 years old) were also found to be infected. External symptoms, includingdieback, tiger striped leaves, berry symptoms (shrivelling, insufficient colouring) and apoplexy, resembledthose found on grapevines in Europe and the USA, although the typical tiger stripe symptom was observedless frequently. The internal stem and trunk symptoms were similar to European symptoms, and includedwhite rot, black and brown wood streaking, brown necrosis within white rot, sectorial brown necrosis andbrown/red/margins next to decay, which often included back lines delimiting white decay. The fungi isolatedmostly from the white rot were basidiomycetes species (30.4%). Black and brown wood streaking was primarily caused by Phaeomoniella chlamydospora (45.4%). Brown necrosis within the white rot was linked to colonization by basidiomycetes (20.4%), Phaeoacremonium aleophilum (15.9%) and Pa. chlamydospora (13.6%). Phaeomoniella chlamydospora (20.8%) and Botryosphaeriaceae species (10.7%) were isolated the most fromthe sectorial brown necrosis and Pa. chlamydospora (29.1%) from the brown/red margins and black lines next to decay. Given the wide distribution of esca complex wood and foliar symptoms in the grape growing regions investigated, this disease should be considered as an important limiting factor in the productive lifespan of vineyards and the quality of produce from grapevine in South Africa.

Effects of grapevine applications of fosetyl-aluminium formulations for downy mildew control on “esca” and associated fungi

Esca of grapevine is a fungal disease with a complex aetiology that is common in almost all regions of the world where grapes are cultivated. Despite much research, no effective control of the disease has been found. We investigated possible activity of fosetyl-aluminium (fosetyl-Al), an active ingredient in many fungicides against downy mildew, to inhibit development of esca in grapevine and the main pathogens linked to the disease, Phaeomoniella chlamydospora (Pch) and Phaeoacremonium aleophilum (Pal). In greenhouse experiments conducted on vines artificially inoculated with Pch or Pal, we found a reduction in necrosis in the woody tissue. In field experiments conducted over several years statistically significant reductions in the annual and cumulative incidence of the disease symptoms, and in cumulative vine mortality, were seen. The effect of fosetyl-Al treatments on leaf gas exchange, levels of resveratrol and a-viniferin in the wood, and enzymatic activities were also studied. Hypotheses regarding the mechanism of action of fosetyl-Al against esca are outlined, and the possible use of products containing the chemical, applied on foliage to control downy mildew, is discussed as a strategy for control of esca.

Control of Eutypa dieback in grapevines using remedial surgery

A series of long-term trials was established to monitor the effect of remedial surgery for the control of Eutypa dieback in commercial vineyards of South Australia. Removing infected cordons and trunks has been used as a strategy for managing Eutypa dieback in grapevines for many years and this study is the first to provide evidence of its effect in controlling the disease. Between 42 and 100% of vines produced watershoots after removal of infected wood, depending on time after surgery and height of the trunk remaining. Remedial surgery reduced the incidence of vines with foliar symptoms of Eutypa dieback in vineyards, and the severity of those symptoms, but the efficacy varied with the presumed extent of pre-existing infection and the origin of the watershoot. It is recommended that all stained wood and a further 10 cm of healthy tissue be removed to reduce the likelihood that symptoms of Eutypa dieback will recur.

Histo-pathology study of the growth of Trichoderma harzianum , Phaeomoniella chlamydospora and Eutypa lata on grapevine pruning wounds

Protecting grapevine pruning wounds by inoculating them with Trichoderma spp. can preventinfection from trunk disease pathogens. The growth and interactions of both, the biological control agent Trichoderma spp. and the vine pathogens, are not well understood. Green fluorescent protein (GFP)-labelled Trichoderma harzianum and red fluorescent protein (DsRed)-labelled T. harzianum , were dual-inoculatedwith Phaeomoniella chlamydospora (DsRed) or Eutypa lata (GFP) on fresh pruning wounds of one-year-oldCabernet Sauvignon and Sauvignon blanc shoots. The inoculated fungi were recovered from varying depthswithin the shoots at 30-day-intervals for 90 days. Trichoderma harzianum suppressed the pathogens and grew deeper in the presence of the pathogens than when it was singly inoculated; possibly an indication of pathogen recognition and competitive response. Eutypa lata was completely eliminated from Sauvignon blancin dual-inoculated canes after 90 days. The mycelium of P. chlamydospora (DsRed) grew extensively in thexylem vessels and possibly contributed to vessel occlusion. Phaeomoniella chlamydospora and E. lata caused blockage of the vessels and thickening of the vessel walls. Grapevine wood produced both tyloses and gums (gels) that blocked xylem vessels as a result of infection. A thickening of the cell walls of xylem fibres occurredonly in E. lata -inoculated shoots, indicative of a different mode of pathogenesis from P. chlamydospora .

Dying on the vine: how Phylloxera transformed wine

Dying on the vine: how Phylloxera transformed wine

Study of genetic relationships between wild and domesticated grapevine in the north of Morocco

In Morocco, knowledge about the wild grapevines has been absent. Until now, no accurate inventory was available and the characterization of this wild grapevine group was lacking. In the present work, prospecting conducted in the North of Morocco (Rif) permitted us to inventory 18 sites with wild grapevines (10 to 50 km away from each other). A total of 168 individuals have been found. This material was analyzed with the 20 nuclear, 3 chloroplast SSR markers and 2 genes involved in the anthocyanin metabolic pathway. We compared the diversity of this material with 48 individuals from cultivated grapevines prospected in the same region, 50 cultivated grapevines from Tunisia and 30 from Algeria along with 128 wild grapevines from France. The diversity observed in the Moroccan wild group was slightly higher compared to other groups. Studies of the genetic structure were then carried out. Within the wild grapevines, the French and Moroccan samples were well differentiated. The wild group (of French or Moroccan origin) was also differentiated from the cultivated, thus revealing the wild status of this indigenous material. The analyses of the sequences showed the same SNP in the different group but the haplotypes reconstruction revealed the presence of specific haplotypes in the Moroccan material when compared with the cultivars group used in this study. This work, confirms the existence and the interest in the conservation of the wild grapevine in Morocco. We suppose that these wild vines contain interesting genes which facilitate the adaptation of grape to its environment. Key words: Vitis vinifera, gene flow, genetic diversity, Morocco, plant conservation genetics.