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Wine grape production is an important economic asset in many nations; however, a significant proportion of vines succumb to grapevine trunk pathogens, reducing yields and causing economic losses. Cover crops, plants that are grown in addition to main crops in order to maintain and enhance soil composition, may also serve as a line of defense against these fungal pathogens by producing volatile root exudates and/or harboring suppressive microbes. We tested whether cover crop diversity reduced disease symptoms and pathogen abundance. In two greenhouse experiments, we inoculated soil with a 106 conidia suspension of Ilyonectria liriodendri, a pathogenic fungus, then conditioned soil with cover crops for several months to investigate changes in pathogen abundance and fungal communities. After removal of cover crops, Chardonnay cuttings were grown in the same soil to assess disease symptoms. When grown alone, white mustard was the only cover crop associated with reductions in necrotic root damage and abundance of Ilyonectria. The suppressive effects of white mustard largely disappeared when paired with other cover crops. In this study, plant identity was more important than diversity when controlling for fungal pathogens in vineyards. This research aligns with other literature describing the suppressive potential of white mustard in vineyards.
Andrew Richards; Mehrbod Estaki; José Ramón Úrbez-Torres; Pat Bowen; Tom Lowery; Miranda Hart. Cover Crop Diversity as a Tool to Mitigate Vine Decline and Reduce Pathogens in Vineyard Soils. Diversity 2020, 12, 128 .
AMA StyleAndrew Richards, Mehrbod Estaki, José Ramón Úrbez-Torres, Pat Bowen, Tom Lowery, Miranda Hart. Cover Crop Diversity as a Tool to Mitigate Vine Decline and Reduce Pathogens in Vineyard Soils. Diversity. 2020; 12 (4):128.
Chicago/Turabian StyleAndrew Richards; Mehrbod Estaki; José Ramón Úrbez-Torres; Pat Bowen; Tom Lowery; Miranda Hart. 2020. "Cover Crop Diversity as a Tool to Mitigate Vine Decline and Reduce Pathogens in Vineyard Soils." Diversity 12, no. 4: 128.
Several virus diseases cause damage to Vitis vinifera L., but information on their incidence and impact on hybrid cultivars is scarce, particularly under cool-climate conditions. In Nova Scotia (NS), the wine industry is based predominantly on interspecific hybrid cultivars. To understand the occurrence of major grapevine viruses in NS, surveys were conducted in 2016, 2017 and 2018. Nine hundred sixty-five composite five-vine samples, collected from 35 hybrids and 18 V. vinifera vineyard blocks, were tested for grapevine leafroll-associated virus 1 (GLRaV-1), GLRaV-2, GLRaV-3, and GLRaV-4, grapevine fanleaf virus (GFLV), grapevine red blotch virus (GRBV), and grapevine Pinot gris virus (GPGV) by PCR/RT-PCR. Overall, 3.4% of the samples were positive for GLRaV-1, 22.8% for GLRaV-3, 0.9% for GFLV, 4.6% for GRBV, and 3.2% for GPGV. None of the 575 samples collected in 2016 and 2017 tested positive for GLRaV-2 or GLRaV-4. Mixed infections by more than one virus occurred in 3% of the composite samples. Of 671 hybrid and 294 V. vinifera samples tested, 38.3% and 27.6% were positive for at least one of the viruses (GLRaV-1, -3, GFLV, GRBV and GPGV), respectively. Phylogenetic analysis of GLRaV-1, -3, GFLV and GPGV revealed the presence of global variants. Complete genome characterization and phylogenetic analysis of nine GRBV isolates grouped three into clade I and six into clade II, indicating the presence of two variants. These findings, along with preliminary reports of insect vectors, establish the first epidemiological framework of the major viral diseases in NS, highlighting the need for long-term management strategies. Plusieurs virus peuvent causer des dommages à Vitis vinifera L., mais l’information sur leur incidence et leur portée sur les cultivars hybrides est rare, particulièrement dans les climats frais. En Nouvelle-Écosse (N.-É.), l’industrie viticole repose principalement sur des cultivars hybrides interspécifiques. Afin de comprendre l’occurrence des principaux virus de la vigne en N.-É., des études ont été menées en 2016, 2017 et 2018. En tout, 965 échantillons composites de 5 vignes, obtenus de 35 hybrides et de 18 parcelles de vignobles, ont été testés par RT-PCR/PCR pour le virus 1 associé à l’enroulement de la vigne (GLRaV-1), le GLRaV-2, le GLRaV-3 et le GLRaV-4, le virus du court noué (GFLV), le virus de la tache rouge (GRBV) et le virus du pinot gris (GPGV). Dans la majorité des cas, 3,4 % des échantillons se sont révélés positifs au GLRaV-1, 22,8 % au GLRaV-3, 0,9 % au GFLV, 4,6 % au GRBV et 3,2 % au GPGV. Aucun des 575 échantillons collectés en 2016 et 2017 ne s’est révélé positif au GLRaV-2 ou au GLRaV-4. Des infections mixtes, causées par plus d’un virus, se sont produites chez 3 % des échantillons composites. Des 671 échantillons d’hybrides et des 274 de V. vinifera testés, 38,3 % et 27,6 % se sont révélés positifs à au moins un des virus (GLRaV-1, GLRaV-3, GFLV, GRBV et GPGV), respectivement. L’analyse phylogénétique de GLRaV-1, de GLRaV-3, de GFLV et de GPGV a révélé des variants entiers. La caractérisation du génome entier et l’analyse phylogénétique de neuf isolats de GRBV en ont regroupé trois dans le clade I et six dans le clade II, indiquant l’existence de deux variants. Ces résultats, parallèlement aux mentions préliminaires d’insectes vecteurs, constituent le premier profil épidémiologique des principales maladies virales en N.-É., mettant en évidence le besoin d’élaborer des stratégies de gestion à long terme.
Sudarsana Poojari; Debra L. Moreau; Dieter Kahl; Mark Ritchie; Shawkat Ali; José Ramon Úrbez-Torres. Disease incidence and genetic variability of economically important grapevine viruses in Nova Scotia. Canadian Journal of Plant Pathology 2020, 42, 584 -594.
AMA StyleSudarsana Poojari, Debra L. Moreau, Dieter Kahl, Mark Ritchie, Shawkat Ali, José Ramon Úrbez-Torres. Disease incidence and genetic variability of economically important grapevine viruses in Nova Scotia. Canadian Journal of Plant Pathology. 2020; 42 (4):584-594.
Chicago/Turabian StyleSudarsana Poojari; Debra L. Moreau; Dieter Kahl; Mark Ritchie; Shawkat Ali; José Ramon Úrbez-Torres. 2020. "Disease incidence and genetic variability of economically important grapevine viruses in Nova Scotia." Canadian Journal of Plant Pathology 42, no. 4: 584-594.
Ilyonectria is a weak pathogen known for causing black foot disease in young vines, infecting roots and vascular tissues at the basal end of the rootstock and restricting the movement of water and nutrients. This negatively impacts vine establishment during transplant into the vineyard. Arbuscular mycorrhizal (AM) fungi are symbiotic fungi that associate with most plants and have been shown to mitigate the infection and effect of pathogens. This greenhouse study was designed to determine if the mycorrhizal fungi could mitigate Ilyonectria infection and whether this was dependent on inoculation timing. ‘Riparia gloire’ grapevine rootstocks (Vitis riparia) were infected with Ilyonectria either after AM fungi, at the same time as AM fungi, or to roots that were not inoculated by AM fungi. We measured the abundance using specific markers for both the pathogen and AM fungi. Colonization by AM fungi did not suppress Ilyonectria, but instead increased the abundance of Ilyonectria. Further, mycorrhizal rootstocks did not have enhanced growth effects on physiological parameters when compared to non-mycorrhizal rootstocks. These findings stand in contrast to the general perception that AM fungi provide protection against root pathogens.
Taylor Holland; Patricia Bowen; Vasilis Kokkoris; Jose Ramon Urbez-Torres; Miranda Hart. Does Inoculation with Arbuscular Mycorrhizal Fungi Reduce Trunk Disease in Grapevine Rootstocks? Horticulturae 2019, 5, 61 .
AMA StyleTaylor Holland, Patricia Bowen, Vasilis Kokkoris, Jose Ramon Urbez-Torres, Miranda Hart. Does Inoculation with Arbuscular Mycorrhizal Fungi Reduce Trunk Disease in Grapevine Rootstocks? Horticulturae. 2019; 5 (3):61.
Chicago/Turabian StyleTaylor Holland; Patricia Bowen; Vasilis Kokkoris; Jose Ramon Urbez-Torres; Miranda Hart. 2019. "Does Inoculation with Arbuscular Mycorrhizal Fungi Reduce Trunk Disease in Grapevine Rootstocks?" Horticulturae 5, no. 3: 61.