Search Results (3)

This study evaluated the effects of late pruning and late apical leaf removal on grapevine phenology, fruit composition, yield parameters, xylem sap carbohydrate content, and grape skin polyphenol levels over two consecutive vintages (2022 and 2023). As expected, delayed pruning shifted the phenological stages, with more pronounced delays observed in 2022 than in 2023. However, by August, all the treatments had reached the berry-softening stage, indicating a convergence in ripening. The grape juice composition showed no significant differences in sugar content in 2022; however, in 2023, the °Brix was notably reduced in control vines subjected to late apical defoliation. The titratable acidity and pH remained stable across treatments and years, while the malic acid concentrations were consistently higher in the late-pruned treatments, particularly LP2 (late pruning 2 was performed when the control vines had reached the eight-leaves-folded development stage). Late pruning significantly reduced the yield and bunch size, especially for the 2023 LP2 treatment. In contrast, late apical defoliation had minimal impact on the yield components. Vegetative growth, as assessed by cane diameter and weight, also declined under late pruning. Despite this, the xylem sap analysis revealed no significant changes in the glucose, fructose, or myo-inositol levels, suggesting that the carbohydrate reserves remained unaffected. Notably, LP2 consistently resulted in the highest total polyphenol content in the grape skins across both years, indicating enhanced phenolic maturity. Although the polyphenol concentrations were generally higher in 2023, the treatment effects varied more widely, likely due to the differing environmental conditions. These findings suggest that late pruning—particularly LP2—can be a valuable tool for improving grape phenolic quality, albeit at the cost of reduced yield and vine vigor. This study highlights the importance of site- and season-specific canopy management strategies in balancing fruit quality with productivity under variable climatic conditions. Full article

Traditional winter pruning in dormancy (BBCH-00) as control (C) and three late pruning treatments, LP1 (wool stage—BBCH-05), LP2 (two leaves folded—BBCH-12), and LP3 (four leaves folded—BBCH-14), were applied on Kékfrankos grapevines. The evolution of the phenological growth stages, grape juice, wine analytical parameters, and phenolic composition were evaluated. The quantitative aspects of the grape berry, bunch, yield, and cane were also assessed. Our goal was to reach a decrease in sugar content and an increase in acidity. Delaying or postponing the phenological phases to bring technological and phenolic ripening closer together was also one of our objectives. These were accomplished, but the negative aspects of late pruning, which resulted in a reduction in the diameter and weight of the canes, should also be taken into account. We also found that, the later the late pruning, the more the yield was reduced. By postponing pruning, the phenological phases were also extended. Full article

Various oils can efficiently control a wide range of pests and pathogens on plants. In this study, we tested the effectiveness solely applied paraffin oil (PFO) spraying against Erysiphe necator, the causal agent of grape powdery mildew (GPM). Its effects on gas exchange and yield at harvest were also investigated. Experiments were conducted in Eger between 2013 and 2014 with two cultivars (Kékfrankos and Chardonnay) showing differing susceptibility to GPM. Treatments with 2.2 and 3.3 v/v% PFO spraying inhibited GPM; however, this effect was influenced by the individual resilience of the variety and the infection pressure of the vintage. The PFO treatment caused decreased leaf gas exchange parameters compared to conventional treatment. The berry yield was also lower in PFO-treated parcels, although yield may be affected by numerous factors and requires further investigation. The mineral oils may have a phytotoxic effect on the grapevine through impairment of the photosynthetic performance, although this effect cannot be connected to a particular PFO concentration according to our research results. This negative effect of PFO highly depends on the ampelographic characteristics of the examined cultivars and vintage. In addition, the physical properties of the spraying agent may also play an important role. Full article