Adjacent Vineyards Research Articles

Foliage and ground spiders respond differently to a semi‐natural habitat‐vineyard gradient

AbstractNatural vegetation in and around crops effectively increases predators. Semi‐natural habitats (SNHs; non‐crop vegetation) surrounding crops provide refuge and resources. However, the function of SNHs may depend on several factors, and the response of natural predators may vary among crops and regions. Here, we examined the spider community in a SNH and at an adjacent vineyard in a semi‐arid region of Argentina. We collected spiders in a gradient from an adjacent SNH, towards the vineyard at three distances from the SNH using two techniques: beating and pit‐fall traps. We collected spiders in December and February during two consecutive years at two strata: in vegetation and on the ground. In vegetation, spider abundance significantly decreased from SNH towards the interior of the vineyard at 80 m. On the ground, spider abundance was also significantly higher in SNH. However, after decreasing at the 5 and 20 m sites inside the vineyard, the abundance increased at 80 m. For foliage spiders, species richness followed the same pattern as abundance, whereas ground spider richness significantly increased from SNH to the interior of the vineyard. Species composition also showed different tendencies between foliage and ground spiders. The foliage spider community differed between SNH vs. all the vineyard sites. Contrarily, at the ground stratum, SNH was similar in composition to the edge of the vineyard, and they both differed from the other vineyard sites. We found that the adjacent SNH influenced the spider community in the vineyard and that this effect depended on the distance from that habitat and the association of the community to various strata. These results highlight the importance of studying the whole community of spiders when aiming to increase predator abundance to enhance biological control in this kind of crop. In addition, we found species that may act as indicators of native vegetation which has important implications for the management of natural habitats in this region.

Characterisation of the vertical temperature gradient in the canopy reveals increased trunk height to be a potential adaptation to climate change

Given the important role of temperature in vine development and grape composition, climate change has already impacted wine production. Adaptation strategies are needed in order to sustain the production of wines and maintain their typicity. Several levers of adaptation are possible, including the use of more heat and drought tolerant plant material, relocating the vineyard and adaptations in the cellar. The training system is also a potential lever for adaptation that is relatively easy to implement. Taking that avenue, a study of the vertical thermal gradient in the vine canopy was carried out in order to determine whether trunk height could be an adaptation strategy for manipulating micro-climate in the bunch zone. Temperature was measured at four different heights from the soil (30, 60, 90 and 120 cm) in two adjacent vineyard parcels. One parcel was managed with cover crop and the other by tilling the soil. The results of this study show that increased trunk height is not likely to significantly delay ripeness, but it could minimise the potential damages of both frost and heat wave events. Type of parcel management was found to have an effect: close to the ground, the cover crop parcel generally had lower minimum temperatures and higher maximum temperatures in comparison to the tilled parcel, exposing the vines to an increased risk of both frost and heat wave damage. When investigating the factors driving the vertical thermal gradient, soil moisture and weather type were found to have an impact. Some of these factors, like mean temperature and soil moisture, may exacerbate the vertical temperature gradient of maximum temperature in a climate change context and increase the risk of damages due to extreme temperatures.

Influence of grapevine age on general physicochemical and phenolic parameters of Rabigato (Vitis viniferaL.) white variety: Results from three vintages

The preservation of the old vine heritage, combined with the fact that old vines could present greater resistance to biotic and abiotic factors, has led to an increase in research studies about the contribution of vine age on grape and wine quality. Thus, the main goal of this work was to evaluate the potential influence of grapevine age on several general physicochemical and phenolic parameters during grape maturation of a Rabigato white grape variety. Therefore, grapes from two adjacent vineyards, with an age difference of 30 years (one with 20 years and the other with 50 years, at the beginning of this study) were studied. At technological maturation, the results obtained for the three consecutive vintages studied (2019 to 2021), and for the general physicochemical parameters analysed, do not seem to indicate a clear differentiation between the grape musts obtained from the younger and the older vineyards. However, for grape phenolics, the results suggest that vine age could be a potential factor on phenolic content, nevertheless not totally confirmed by the results at technological maturation during the three consecutive vintages considered. With this work we will contribute to expand the knowledge about the potential impact of the vine age on grape composition.

Insecticide resistance in California populations of the glassy-winged sharpshooter Homalodisca vitripennis.

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar), is a primary vector of Pierce's disease of grapes in California. Systemic imidacloprid treatments have been the mainstay of area-wide treatment programs that were established in the Central Valley (Kern and Tulare Counties) and Southern California (Riverside County) during the 1990s to combat the pest. The programs helped to suppress populations on citrus, a major sharpshooter host, to levels that significantly reduced migration into adjacent vineyards. However, beginning in 2012, there has been a resurgence of glassy-winged sharpshooter populations in Kern and Tulare counties, and hitherto successful treatment strategies have not been as effective. This study investigated the possibility that insecticide resistance was a contributing factor to the population resurgence. Topical application bioassays detected high levels of resistance to imidacloprid in Kern and Tulare populations, and lower levels of resistance (perhaps due to cross-resistance) to the foliar neonicotinoid acetamiprid (20-fold), the pyrethroid fenpropathrin (7.4-fold), and the butenolide flupyradifurone (4-fold). Samples of glassy-winged sharpshooters from citrus groves under organic management also exhibited high levels of imidacloprid resistance. The long-term use of imidacloprid has selected for resistance in glassy-winged sharpshooters. The most resistant populations also exhibited resistance to the foliar neonicotinoid acetamiprid, the pyrethroid fenpropathrin, and the butenolide flupyradifurone. High levels of imidacloprid resistance in insects sampled from organic groves indicate that resistant insects are migrating from nearby conventional groves, which could compromise the control of sharpshooters in organic systems with insecticides affected by cross-resistance. © 2021 Society of Chemical Industry.

Die Wolfspinne Alopecosa farinosa (Araneae: Lycosidae) im Rebgelände des Kaiserstuhls: Populationsaufbau und Populationsdynamik in einem Zeitraum von 33 Jahren

Alopecosa farinosa (Herman, 1879) is a photophilic and xerophilic wolf spider. It lives in the Kaiserstuhl in a large area, but only in non-wooded sites. It prefers south orientated slopes and adjacent vineyards. Alopecosa farinosa apparently does not balloon. It seems that the mother contributes to dispersal by carrying the juveniles around on the opisthosoma. Since 1979 we performed a continuous long-term study on the recolonization and succession of vineyard slopes after large scale land consolidations. This data from over 33 years shows an undulating trend of population development with a density variation of factor 3, superimposed by short time fluctuations caused by the weather. Alopecosa farinosa has a one-year generation cycle. The present long-time study provides an overview of 33 generations. Due to climatic changes in the last years the winters were warm. Consequently, Alopecosa farinosa changed from a stenochronic spring species to a stenochronic winter species.

Influences of blackberry margins on population dynamics of Drosophila suzukii and grape infestation in adjacent vineyards

AbstractUnderstanding the dynamics of pest insect populations in relation to the presence of non‐crop habitats and infestation levels of adjacent crops is essential to develop sustainable pest management strategies. The invasive pest species Drosophila suzukii (Diptera: Drosophilidae) is able to utilize a broad range of host plants. In viticulture, scientific risk assessment for D. suzukii has only recently started and studies assessing the effects of field margins containing wild host plants on D. suzukii population dynamics and on infestation risks in adjacent vineyards are lacking. Thus, in a one‐year field study, the role of different field margins on fly abundance and crop infestation in adjacent vineyards of Vitis vinifera, variety “Pinot Noir,” were investigated. Different monitoring methods were conducted to assess fly distribution, sex ratio and grape infestation in 14 vineyards adjacent to field margins containing either blackberry (BB) Rubus spp. or non‐host (NH) plants. Our results show that blackberries strongly enhanced D. suzukii abundance within field margin vegetation all year long, whereas fly abundance in vineyards adjacent to BB margins was just enhanced in some seasonal periods. Moreover, the influence of BB margins was limited by distance. However, high fly numbers in BB field margins did result in zero egg infestation of “Pinot Noir” berries. These results may have important implications for winegrowers to make efficient management decisions: regardless of high abundance of adult D. suzukii, only grape berry monitoring can assess the actual infestation risk and the potential need to take management action.

Ground greening in vineyards promotes the Woodlark Lullula arborea and their invertebrate prey

Vineyards are intensively managed monocultures, constituting homogeneously cultivated landscapes. They often have a mineral appearance, not only because they occur mostly in xeric biomes but also as a result of the herbicide treatments used to combat ground vegetation. However, new vineyard management practices are being developed that tolerate more vegetation cover on the ground, potentially having positive impacts on biodiversity. We have investigated the effects of ground greening on habitat preferences of the Woodlark (Lullula arborea), an emblematic, insectivorous passerine typical of vineyards in central and southern Europe. We first investigated the role of ground vegetation cover and plant species richness on habitat use by Woodlarks, while accounting for various additional habitat characteristics. Second, we assessed whether the dependence of Woodlarks on ground vegetation cover could be mediated by an increased occurrence of invertebrate prey. Ground-dwelling invertebrates were sampled with pitfall traps placed in vineyard fields visited by Woodlarks (presence fields) and in adjacent vineyards where Woodlarks had not been observed (pseudo-absence fields). We show that increased ground vegetation cover, plant species richness and wider inter-rows were the main drivers of Woodlark occurrence. Overall invertebrate prey abundance increased with ground vegetation cover. Similarly, the abundance and number of beetle and spider families were primarily driven by increased ground vegetation cover, plant species richness or wider inter-rows. We conclude that less intensive management, which involves the restricted use of herbicides and concomitantly favors a diverse plant community, promotes Woodlarks and their invertebrate prey, thus having a positive impact on vineyard biodiversity at multiple trophic levels.

Relationship between the geology, soil assessment, and terroir of Gewürtztraminer vineyards: A case study in the Dolomites of northern Italy

The study of the geological identity of rare vineyards introduces new classification approaches for the geological natural environment, which is sometimes underestimated in agriculture. This research examines the geological features related to quaternary soil sediments in the Italian Alps, near the village of Tramin. The local winemakers have constantly encountered differences between vineyards over the decades, such as growth of vines and quality of the grapes and wine, even in Gewürtztraminer vineyards close to each other. A detailed geological territorial study with more precise classification at the vineyard scale would therefore be significant, because it could explain the source of these differences. A new term for this approach, Vineyard Geological Identity (VGI), has been coined. The purpose is to standardize the geological information and enhance scientific comparisons between vineyards, but it is also useful for vintners as they attempt to obtain scientific confirmation for their personal observations or for supporting the territorial subdivision provided by the wine's product quality specification. Our findings show a very marked variability of sediments in the study area and how the more recent geological processes are directly related to their varied chemical and mineralogical distributions. Many dolomitic or silicate soil sediments marked by different history, and therefore with different chemical and physical properties, lie adjacent in a very restricted territory. Some of the analysed vineyards are evidently siliciclastic, whereas others are mostly carbonate. In adjacent vineyards, the content of carbonate mineral can range from 36.3% to 0.6%. A marked alternation of layers with different mineralogy can typify the sediment layers where the grapevine root systems grow. The Mn and dolomitic Mg mean concentration were 1.1 mg/kg and 343 mg/kg, respectively, in strictly siliciclastic layers compared with 6.9 mg/kg and 1081 mg/kg in the more carbonate layers. Several minerals characterize the different sediments, and relations between some of them and the fruit orchard soil reaction classes were found. Further studies should verify direct links with the biochemical processes related to the variable mineral macronutrients observed. A correct geopedological classification and mapping of both the sediments and related soils are essential to eliminate incongruities in the interdisciplinary data.

A multi-year intercomparison of micrometeorological observations at adjacent vineyards in California’s Central Valley during GRAPEX

California is among the largest wine-producing regions in the world. It is also a region with limited water resources. To ensure that scarce water resources are used effectively, the ongoing Grape Remote sensing Atmospheric Profile and Evapotranspiration eXperiment (GRAPEX) project seeks to improve irrigation management within vineyards by providing remote sensing-based tools that can monitor ET across the continuum from sub-vineyard to regional scales. This study, which was conducted as a part of the GRAPEX project, compares the surface fluxes collected over a pair of vineyards separated by approximately 1 km from 2013 to 2017 to better understand the role of environmental conditions in controlling evapotranspiration. A comparison of the meteorological conditions, which include wind speed, wind direction, air temperature, water vapor pressure, and atmospheric pressure, showed there was no statistically meaningful difference in the measurements of these quantities either between the two vineyards or year to year. In contrast, the comparison of the surface fluxes, and in particular the sensible heat (H) and latent heat (λE) fluxes, showed that there were large inter-site and inter-annual differences. On average, during the growing seasons, H differed by 28 W m−2, while λE differed by 32 W m−2. With coefficients of determination (r2) in excess of 0.90, the differences in the surface fluxes can be largely explained by differences in leaf area index (LAI) and soil moisture content. Since these quantities are, in turn, dependent on vineyard management practices, this work highlights the importance of management decisions for ensuring that limited water resources are used effectively.

Diversity of arbuscular mycorrhizal fungi in no-till and conventionally tilled vineyards

The use of a permanent vegetation cover or frequent tillage in vineyards may affect soil water budget, nutrient availability, soil compaction, soil erosion and soil microbe biodiversity, and through all these and other factors also yield and wine quality parameters. The abundance and diversity of arbuscular mycorrhizal fungi (AMF) might also be influenced, but so far effects on AMF by permanent vege-tation cover (= no-tillage systems) or repeated chiseling and rotary-tillaging have rarely been compared in vineyards. The objective of this on-farm study was to determine AMF species richness and diversity in two adjacent vineyards in Palatinate (SW Germany). In both vineyards, grown on fertile Luvisols, the var. “Pinot Gris” was grown for 39 years, but with different soil cultivation and different fertilization strategies. In one vineyard, soil was maintained periodically without vegetation by passing rotatory cultivator and chiseling between the grapevine rows (‘inter-rows’) several times per year, preferably during spring and summer and in dependency of rainfall and ‘weed’ growth, and fertilization was mainly by organic fertilizers in the last ten years before soil sampling. In the other vineyard, a permanent vegetation has been established since planting, dominated by Lolium perenne, and mineral fertilizers were exclusively applied. Despite of similar high nutrient availability in both soils, in particular of phosphorus, astonishing high AMF species richness and diversity were found in both vineyards. In the no-tillage inter-rows, 34 AMF species were found, with a species composition typically for Central European permanent grasslands (Shannon diversity index 2.45). In the tillage system 24 AMF species were found with a composition as known for extensively used, cultivated Central European croplands (diversity index 2.26). We conclude that above all soil cultivation has affected AMF diversity in these Central European vineyards, while the level and type of fertilization affected the AMF communities only on a minor level.

Row Orientation and Defoliation Effects on Grape Composition ofVitis viniferaL. Agiorgitiko in Nemea (Greece)

Vineyard row orientation and canopy side exert a significant role in determining grape microclimate. The latter can be further manipulated by selective defoliation in the bunch zone. The aim of this study was to investigate the combined effects of row orientation and basal leaf removal on grape ripening of Vitis vinifera L. cv. Agiorgitiko in Nemea, Southern Greece. The experiment was conducted in 2017, on two adjacent vineyard blocks planted in 1990 on a flat site with two row orientations, North-South and East-West. Both blocks were grafted onto 41B rootstock and trained on a double cordon vertical trellis with uniform vineyard operations. Defoliation treatments included full leaf removal in the bunch zone performed at berry set and a non defoliated control, replicated three times in both blocks. Grapes were sampled at three time points from veraison to harvest from all canopy sides (i.e. E and W on North-South oriented rows and N and S on East-West oriented rows) and defoliation treatments and were analyzed for yield components and berry chemical composition. In addition, approximately 5 kg of grapes were collected from all plots and processed according to a standard winemaking protocol. Total yield and berry mass were lowest in the W-exposed and in the defoliated grapes. Must sugar and acid content, as well as wine alcohol and acidity did not depend on either factor. Skin anthocyanins and phenolics generally increased with defoliation. Skin anthocyanins and total berry phenolics were highest for north-south oriented rows, in the grapes of the cooler canopy side (E). Wines made from grapes of the E and W canopy sides showed the highest wine color, phenolic richness and the lowest pH. No interaction between row orientation and defoliation was detected for any of the measured parameters. According to the results, the E-facing grapes on the north-south oriented rows showed generally a superior grape and wine composition for Agiorgitiko variety, under the semiarid conditions of the Nemea area.

The relationship between <i>Epiphyas postvittana</i> (lightbrown apple moth, Lepidoptera: Tortricidae) in pipfruit orchards and adjacent vineyards in Nelson


 
 
 The lightbrown apple moth (Epiphyas postvittana) is the most abundant leafroller species infesting apple orchards and vineyards in the Nelson region. This study was undertaken to investigate concerns from some orchardists of leafroller pressure on their apple blocks adjacent to neighbouring vineyards. Lightbrown apple moth pheromone trap catches were recorded inside orchards and in neighbouring vineyards and in boundary rows of the orchards closest to a vineyard during 2012—13. The vineyards were not treated with insecticide and the orchards received ve applications of insecticide between November and mid- March to control lepidopteran pests. The highest catches of leafrollers were recorded in vineyards and catches increased during the season to peak in April. The increasing leafroller population in vineyards was associated with higher catches of leafrollers in boundary rows of the orchard closest to the vineyard. Leafroller catches inside the orchards were lower while insecticide sprays were being applied. The higher pheromone trap catches of leafrollers in the vineyards and on the orchard boundary were associated with the most leafroller sign that was found in these locations during timed searches. These results suggest that high populations of leafrollers in vineyards can increase leafroller pressure on nearby pipfruit orchards.
 
 

Occurrence of Fruit-Decaying Fungi on Adult Male Mediterranean Fruit Flies (Ceratitis capitata) Captured in Orchards and Adjacent Vineyards

The occurrence of adult male Ceratitis fruit flies and their potential to transmit fungi associated with pre- and postharvest decay of fruit in natura were investigated. Sensus fruit-fly traps were installed in orchards each bordering on a vineyard on farms in the Stellenbosch region, South Africa. Ceratitis fruit flies were collected weekly, identified and counted to determine the fluctuations in fruit-fly population levels. Captured fruit flies were plated on a semi-selective medium and the number of flies yielding the fungi was recorded. Both the Mediterranean fruit fly (C. capitata), and the Natal fruit fly (C. rosa) were trapped. C. rosa seldom occurred and comprised only 1 % of the total number of flies captured. Fruit-fly patterns showed that early infestation of orchards may contribute to the infestation of adjacent vineyards later in the season. At localities where flies were not trapped in the early season, infestation usually occurred in the orchards and adjacent vineyards in the late season, and well after fruits were harvested. Fruit flies from all localities yielded species of Alternaria, Penicillium, Aspergillus, Rhiwpus, Mucor and Botrytis cinerea on the medium. Of the different fungi, Alternaria and Penicillium spp. were most commonly carried by the flies at the various localities. The organisms occurred in a specific pattern on flies captured at a specific locality, and in a given orchard or vineyard. The pattern of fruit-fly infestation and their fungal contamination suggest that the Mediterranean Fruit-fly has the potential to transfer fungi associated with post-harvest decay in natura from early-season to mid- and late-season peach and plum orchards, and to neighbouring mid- and late-season wine and table grape vineyards. This highlights the importance of fruit-fly management in order to control disease epidemics in orchards and vineyards.

Variability of breeding resource partitioning in a lacertid lizard at field scale

Human activities cause increasingly deep alterations to natural environments. Yet, the effects on vertebrates with low dispersal capacity are still poorly investigated, especially at field scale. Life history variation represents one means by which species can adapt to a changing environment. Among vertebrates, lizards exhibit a high degree of variation in life-history traits, often associated with environmental variability. We examined the female breeding output ofPodarcissiculus(Lacertidae) inside agricultural habitats, to test whether different cultivation and management influence the life-history traits of this species. Interestingly, we recorded variability of female breeding output at a very fine scale, namely among adjacent vineyards and olive orchards under different management levels. Lizards displayed the lowest breeding effort in the almost unmanaged sites, while clutch mass, relative fecundity and mean egg mass slightly increased in more intensively managed sites. However, in the most intensive cultivations we detected a life-history trade-off, where eggs from larger clutches tended to be relatively smaller than eggs from smaller clutches. This pattern suggests that agriculture can influence lizard reproductive output, partly favouring it in the presence of medium intensity cultivation but causing, in the most intensively managed sites, some environmental constraints that require a peculiar partitioning of the breeding resources. Even though further studies are needed to clarify the mechanisms driving the observed pattern, our results can be considered a starting point for evaluating the analysis of lizard breeding features as a tool to assess the impact of human activities, at least in agricultural environments.

The Influence of Genotype and Environment on Small RNA Profiles in Grapevine Berry

Understanding the molecular mechanisms involved in the interaction between the genetic composition and the environment is crucial for modern viticulture. We approached this issue by focusing on the small RNA transcriptome in grapevine berries of the two varieties Cabernet Sauvignon and Sangiovese, growing in adjacent vineyards in three different environments. Four different developmental stages were studied and a total of 48 libraries of small RNAs were produced and sequenced. Using a proximity-based pipeline, we determined the general landscape of small RNAs accumulation in grapevine berries. We also investigated the presence of known and novel miRNAs and analyzed their accumulation profile. The results showed that the distribution of small RNA-producing loci is variable between the two cultivars, and that the level of variation depends on the vineyard. Differently, the profile of miRNA accumulation mainly depends on the developmental stage. The vineyard in Riccione maximizes the differences between the varieties, promoting the production of more than 1000 specific small RNA loci and modulating their expression depending on the cultivar and the maturation stage. In total, 89 known vvi-miRNAs and 33 novel vvi-miRNA candidates were identified in our samples, many of them showing the accumulation profile modulated by at least one of the factors studied. The in silico prediction of miRNA targets suggests their involvement in berry development and in secondary metabolites accumulation such as anthocyanins and polyphenols.

Use of Falconry to Deter Nuisance Birds in Leafy Greens Fields in Northern California

Author(s): Navarro-Gonzalez, Nora; Jay-Russell, Michele T. | Abstract: Some species of birds form large flocks that forage on agricultural fields and frequently damage the crop, resulting in significant economic losses. Additionally, by defecating they potentially contaminate the crop and farm equipment with pathogens, which is of special concern for leafy greens that are consumed uncooked. There is a need to find an effective deterrent that is also environmentally friendly, and falconry is an ideal candidate for this purpose. To evaluate falconry as deterrent of nuisance birds in leafy greens field in northern California, we performed a set of trials on a control ranch and a treatment ranch of similar production and landscape characteristics. We identified avian species, counted individuals, and recorded flock size in daily surveys pre-treatment, during treatment (falconry), and post-treatment. Bird abundance was lower in spring than in fall, probably because many fields were fallow in spring. In both seasons, we observed a large daily variation in the bird abundance and their use of the fields in the surveys pre-treatment. In fall, the first trial was interfered by the activity of a falconer in an adjacent vineyard and the harvest of the grapes. Importantly, in the second trial, use of the field (e.g., foraging, etc.) decreased during five days of treatment and continued to be low for three days post-treatment, suggesting a “memory effect” after hazing by falconry. Interestingly, the third fall trial coincided with the end of the leafy greens growing season and showed that falconry successfully minimized use of the field by nuisance birds during peak activity. These results indicate that falconry is an effective measure to protect leafy green crops from fecal contamination and damage, but further research is needed at more farms in different regions, and the effect of using falconry in combination with other non-lethal bird abatement approaches (e.g., audio-visual deterrents) should also be evaluated.

Soil organic carbon and microbial communities respond to vineyard management

AbstractThe farming practices in vineyards vary widely, but how does this affect vineyard soils? The main objective of this study was to evaluate the effects of vineyard management practices on soil organic matter and the soil microbial community. To this end, we investigated three adjacent vineyards in the Traisen valley, Austria, of which the soils had developed on the same parent material and under identical environmental/site conditions but were managed differently (esp. tillage, fertilizer application, cover crops) for more than 10 yrs. We found that topsoil bulk density (BD) decreased with increasing tillage intensity, while subsoil BD showed the opposite trend. Soil organic carbon (SOC) stocks in 0–50 cm depth increased from 10 kg m−2 in an unfertilized and frequently tilled vineyard to 17 kg m−2 in a regularly fertilized but less intensively tilled vineyard. Topsoil microbial biomass per unit SOC, estimated by the sum of microbial phospholipid fatty acids (PLFAs), followed this trend, albeit not statistically significantly. Principal component analysis of PLFA patterns revealed that the microbial communities were compositionally distinct between different management practices. The fungal PLFA marker 18:2ω6,9 was highest in the vineyard with the lowest amount of extractable Cu (by 0.01 m CaCl2), and the bacterial‐to‐fungal biomass ratio was positively correlated with extractable Cu. Our results indicate that tillage and fertilizer application of vineyards can strongly affect vineyard soil properties such as BD and SOC stocks and that the application of Cu‐based fungicides may impair soil fungal communities.

Clonal differences and impact of defoliation on Sauvignon blanc (Vitis vinifera L.) wines: a chemical and sensory investigation.

The aim of this study, performed on Sauvignon blanc clones SB11 and SB316, grafted on the same rootstock 101-14 Mgt (Vitis riparia × V. ruperstris) and grown at two adjacent vineyards, was two-fold: (1) to study wine chemical and sensory composition of both clones within an unaltered canopy; and (2) to determine the effect of defoliation (e.g. bunch microclimate) on wine chemical and sensory composition. Orthogonal projection to latent structures discriminate analysis (OPLS-DA) was applied to the concentration profiles of volatile compounds derived from gas chromatography-mass spectrometry data. The loadings directions inferred that 3-isobutyl-2-methoxypyrazine (IBMP) discriminated control treatments (shaded fruit zone) of both clones from defoliation treatments (exposed fruit zone), whereas 3-sulfanyl-hexan-1-ol (3SH), 3-sulfanylhexyl acetate (3SHA), hexanol, hexyl hexanoate and some other esters discriminated defoliated treatments from the controls. The OPLS-DA indicated the importance of IBMP, higher alcohol acetates and phenylethyl esters, for discrimination of clone SB11 from clone SB316 irrespective of the treatment. Defoliation in the fruit zone significantly decreased perceived greenness in clone SB11 and elevated fruitier aromas, whereas in clone SB316 the effect of defoliation on wine sensory perception was less noticeable regardless the decrease in IBMP concentrations. These findings highlight the importance of clone selection and bunch microclimate to diversify produced wine styles.

Plant Water Stress Effects on the Net Dispersal Rate of the Insect Vector <I>Homalodisca vitripennis</I> (Hemiptera: Cicadellidae) and Movement of Its Egg Parasitoid, <I>Gonatocerus ashmeadi</I> (Hymenoptera: Mymaridae)

Homalodisca vitripennis (Germar), a vector of Xylella fastidiosa, is associated with citrus plantings in California. Infested citrus orchards act as a source of vectors to adjacent vineyards where X. fastidiosa causes Pierce's disease. An analysis of the pattern and rate of movement of H. vitripennis and its egg parasitoid, Gonatocerus ashmeadi Girault, was conducted in a citrus orchard by using a protein mark-capture technique to quantify movement and net dispersal rates in the experimental areas. Treatments included irrigation at 100% of the crop evapotranspiration rate (ET(c)), 80, and 60% ET(c). Sex-specific net dispersal rates showed that H. vitripennis males and females moved consistently and contributed equally to the level of population change within treated areas. Trees irrigated at 60% ET(c) were the least preferred by H. vitripennis. Among all protein-marked individuals captured in the 60% ET(c) treatment, ≈ 75 and 88% in 2005 and 2006, respectively, were inflow individuals. Movement toward less preferable plants indicates that in agricultural landscapes dominated by perennial monocultures, there is a random component to H. vitripennis movement, which may result from the inability of H. vitripennis to use plant visual cues, olfactory cues, or both to make well-informed long-range decisions. The 80% ET(c) areas were a significant source of adult H. vitripennis and G. ashmeadi compared with the other treatments. Colonization rates by parasitoids were synchronized with the spatiotemporal distribution of H. vitripennis eggs. Results suggest that H. vitripennis movement from citrus into adjacent vineyards could be a result of random dispersal rather than oriented movement in response to host-plant characteristics.

Diversity of Saccharomyces and non- Saccharomyces yeasts in three red grape varieties cultured in the Serranía de Ronda (Spain) vine-growing region

For the first time, an ecological survey of wine yeasts present in grapes growing in two vineyards located in the region of “Serranía de Ronda” (Málaga, southern Spain) has been carried out. During the 2006 and 2007 vintages, grapes from different varieties were aseptically collected and allowed to ferment spontaneously in the laboratory. From a total of 1586 colonies isolated from microvinifications, 1281 were identified according to ITS polymorphisms and their identity confirmed by sequencing of the D1/D2 region of 26S rDNA. Most of the isolates (84%) corresponded to thirteen different non- Saccharomyces species with Kluyveromyces thermotolerans, Hanseniaspora guilliermondii, Hanseniaspora uvarum and Issatchenkia orientalis accounting for 42.7% of the total. Mitochondrial DNA restriction analysis from the Saccharomyces cerevisiae isolates revealed a low diversity since only eleven different profiles were found, nine of them corresponding to local strains and two to commercial ones that had been used in different campaigns and that very likely were disseminated from the winery to the adjacent vineyard. A different distribution of strains was found in the three grape varieties studied.