Excessive precipitation events have greatly increased in several grape growing regions due to human-caused climate change. These heavy downpours result in a myriad of problems in the vineyard including soil aggregate breakdown, soil runoff, nutrient leaching, excessive vine vegetative growth, and diseased fruit. The negative impacts of excessive precipitation events on vineyards are exacerbated by the maintenance of bare soil under the vines. Exposure of bare soil results in soil erosion and runoff which pollutes nearby watersheds; raindrops weaken and break apart soil aggregates, leading to increased soil erosivity and contributing to the formation of surface crusts. In addition to excessive precipitation events, some grape growing regions can be characterized by fertile soils. The availability of ample water and nutrients can lead to highly vigorous vines with shoot growth continuing through harvest. Long shoots and large leaves result in shaded fruit, a humid vine microclimate, and excessive cluster rot. In this review, we examined how either natural (i.e., resident) or seeded under-vine vegetation (UVV) can help mitigate many of the problems associated with excessive precipitation. Through providing vegetative coverage to reduce the force of raindrops, increasing soil organic matter and enhancing soil microbial diversity, UVV can reduce the soil degradation and off-site impacts caused by excessive precipitation events. Through competition for soil resources, UVV can reduce excessive vegetative growth of vines and decrease cluster rot incidence and severity, although grapevine response to UVV can be highly variable. We discussed recent advances in understanding below and aboveground vine response and acclimation to UVV and presented current evidence of factors influencing the impact of UVV on vine growth and productivity to assist practitioners in making informed decisions and maximize the ecosystem services provided by UVV.

Spotted lanternfly (Lycorma delicatula White; SLF) is a phloem‐feeding planthopper invasive to the Eastern United States that can feed on a range of wild and cultivated plant species. Since its 2014 introduction in the United States, large infestations and subsequent economic damage have been reported in cultivated grapevines, but no studies have detailed grapevine physiological responses to SLF phloem feeding. This study investigated grapevine‐SLF interactions, detailing how different infestation densities affect leaf gas exchange and end‐season concentrations of nonstructural carbohydrates and nitrogen in vegetative and perennial tissues of two Vitis species. Effects on fruit ripeness parameters and dormant bud freeze tolerance were examined, in addition to other year‐after effects. Phloem feeding by low densities (≤4 SLF shoot⁻¹) had minimal effects, whereas greater densities (5–15 SLF shoot⁻¹) increasingly affected carbohydrate and nitrogen dynamics in both Vitis species. Phloem feeding substantially affected starch and, to a lesser extent, total nitrogen concentrations of woody roots. Prolonged exposure strongly reduced leaf gas exchange. We conclude that intensive late‐season phloem feeding by large adult SLF population densities (≥8 SLF shoot⁻¹) can induce carbon limitation, with the potential for negative year‐after effects in cases of severe belowground carbon depletion. This work presents novel insights into SLF‐grapevine interactions, identifies avenues of future SLF‐plant research, and assists the development of action thresholds for SLF management in vineyards.

Spring frosts and subsequent crop losses threaten the economic sustainability of fruit crop producers all over the world. This study used a controlled-freezing technique to impose a post-budburst freezing stress to grapevine shoots forced from one-node cuttings [‘Albariño’, ‘Cabernet Franc’, ‘Cabernet Sauvignon’, and ‘Pinot Grigio’ ( Vitis vinifera )] and whole plants [‘Noiret’ ( Vitis hybrid)]. Our goal was to investigate the incidence of freeze injury among cultivars, stage of phenological development, and a potassium salt-based fertilizer (KDL) with potential cryoprotectant activity. Among the V. vinifera cultivars, the incidence of mortality of shoots exposed to −3.5 °C was highest for ‘Albariño’ (71%) and lowest for ‘Cabernet Sauvignon’ (51%). Cuttings sprayed with KDL 24 hours before cold temperature exposure exhibited 16% lower shoot mortality and lower osmotic potential (Ψ _s ) (−0.92 MPa) than the unsprayed cuttings (−0.77 MPa). However, application of KDL did not impact shoot mortality for whole ‘Noiret’ vines. Mortality for ‘Noiret’ shoots greatly increased with the advancement of phenological development, ranging from 10% in wooly buds to 78% in shoots ≈10-cm long. The practical significance of KDL remains questionable; cultivar selection still appears to be a more reliable method for avoiding spring frost, by planting late bursting cultivars in more frost-prone areas.

Spring freeze events pose a threat to vineyard productivity worldwide. We compared two methods to delay grapevine budbreak for freeze avoidance and evaluated their effects on phenology, yield components, fruit composition, and postharvest parameters, including wine chemistry, carbohydrate storage, and bud freeze tolerance. The two methods to delay budbreak were: a vegetable oil-based adjuvant (Amigo®) applied to dormant buds at 8% and 10% (v/v) and late pruning applied when apical buds reached approximately Eichhorn-Lorenz stage 7. Treatments were applied in 2018 and 2019 on two Vitis vinifera cultivars, Lemberger and Riesling, and compared to a control treatment (no delayed budbreak strategy applied). Amigo and late pruning delayed budbreak compared to control vines for both years and cultivars. The delay in budbreak varied from three to six days for Amigo 8%, five to eight days for Amigo 10%, and 10 to 11 days later for late pruning. In 2019, there was a freezing event near budbreak; compared to control vines, late-pruned Lemberger vines had lower shoot damage when measured during the growing season and higher yield at harvest. Delayed budbreak treatments did not influence wine chemistry either year or consistently affect carbohydrate storage or bud freeze tolerance the following dormant season. However, in Riesling, late pruning reduced cluster and berry weight by up to 34% and 22%, respectively, compared to control vines. Furthermore, our results indicated Amigo 10% may decrease bud survival when applied to Riesling vines. In general, late pruning more effectively delayed budbreak and mitigated freeze damage than Amigo application without negatively affecting vine health and wine composition; however, the cultivar-dependent effect of late pruning on cluster weight is a consideration prior to adoption.