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IntroductionPruning wounds are the main entry points for fungi causing grapevine trunk diseases (GTDs). Several studies identified factors influencing the temporal dynamics of wound susceptibility, which include the fungal species and inoculum dose, weather conditions, grape variety, pruning date, and so forth. Here, we conducted a quantitative analysis of literature data to synthesise outcomes across studies and to identify the factors that most affect the length of pruning wound susceptibility. MethodsWe extracted data on the frequency at which the inoculated wounds showed GTD symptoms or an inoculated pathogen was reisolated following artificial inoculation at the time of pruning or in the following days. A negative exponential model was fit to these data to describe changes in wound susceptibility as a function of time since pruning, in which the rate parameter changed depending on specific factors. Results and DiscussionThe results show that wound susceptibility is high at the time of pruning, and they remain susceptible to invasion by GTD fungi for months after pruning. Infection incidence on wounds was higher for fungi associated with Botryosphaeria dieback than those associated with Eutypa dieback or Esca complex, and wound susceptibility decreased faster for Eutypa dieback than for other GTD agents. Grapevine variety and pruning season also affected the wound susceptibility period. Sauvignon Blanc remains susceptible to GTDs longer than other varieties. We also found that the time of pruning can affect infection dynamics, especially for more susceptible varieties. The results increase our understanding of GTD epidemiology and should help growers control infections.

This study analyzed the fungicides’ use in viticulture in Veneto (Italy) to control powdery and downy mildews, evaluating how the choice of active ingredients changed during two different periods in the last years, considering the Mode of Action (MoA) and defining future scenarios to control diseases in vineyard, considering all the available solutions to reach an adequate production, and at the same time avoiding the insurgence of new resistance to fungicides and hypothesizing possible further restrictions to actual available fungicides.

Because the risk of resistance towards single-site fungicides in populations of Plasmopara viticola and Erysiphe necator, the causal agents of downy mildew (DM) and powdery mildew (PM), respectively, is substantial, fungicide resistance management is important in vineyards. Available methods for assessing resistance risk mainly focus on single fungicides and do not consider the risk of resistance of a complete fungicide schedule, which typically includes multiple fungicides, used solo or in mixture and at different doses, and other actions (behaviors) of the farmer. A simple scoring method (fungicide resistance risk score, FRRS) was developed to account for both (i) the intrinsic risk due to the fungicides used, the target pathogens, and agronomic factors, and (ii) the behavioral risk, which includes how the fungicides are used during the season. FRRSs were then calculated for 10 representative vineyards (10 cases) and ranked from 1 (highest score) to 10 (lowest score). For comparison, 20 assessors (four winegrowers and 16 experts including public advisors, field technicians, and consultants) ranked the same cases based on their individual “perception of risk” from 1 (highest risk) to 10 (lowest risk). When the FRRS-based rankings were compared with the modes of the rankings provided by the assessors, the correlation coefficients were significant for all experts (P < 0.001) and for each category of experts (P < 0.05); i.e., public advisors, field technicians from agro-chemical companies, and consultants; for non-experts, i.e., winegrowers, the FFRS values were significantly correlated with the modes of rankings for PM (P < 0.001) but not for DM (P = 0.293). The results indicated that the use of the new scoring method, i.e., the use of FRRSs, would reduce the variability in assessments of resistance risks and would provide a common method for evaluating resistance risk by both experts and winegrowers.

Organic vineyards still rely on large external inputs to control harmful organisms (i.e., pests). The BIOVINE project aims to develop natural solutions based on plant diversity to control pests and reduce pesticide dependence. The capability of plants of increasing the ecosystem resistance to pests and invasive species is a well-known ecosystem service. However, monocultures (including vineyards) do not exploit the potential of plant diversity. BIOVINE aims to develop new viticultural systems based on increased plant diversity within (e.g., cover crops) and/or around (e.g., hedges, vegetation spots, edgings) vineyards by planting selected plant species for the control of arthropods, soil-borne pests (oomycetes, fungi, nematodes), and foliar pathogens. Candidate plants will be identified by a literature review, and the selected ones will be tested in controlled environment or small-scale experiments. The ability of the selected plants to: i) attract or repel target arthropod pests; ii) conserve/promote beneficials; iii) control soil-borne pests by means of biofumigation; iv) carry mycorrhizal fungi to the vine root system to increase plant health (growth and resistance); and v) control foliar pathogens by reducing the inoculum spread from soil, will be investigated. New viticultural systems able to exploit plant diversity will then be designed based on results of BIOVINE activities, following a design-assessment-adjustment cycle, which will then be tested by in-vineyard experiments in France, Italy, Romania, Slovenia, Spain and Switzerland for a 2-year period. Innovative viticultural systems should represent an improved way for pest control in organic viticulture, meanwhile they should positively affect functional biodiversity and ecosystem services. New control strategies may provide financial opportunities to vine growers and lower their reliance on pesticides.