Inter-row Vegetation Research Articles

Effects of sown and spontaneous inter-row vegetation on weeds and beneficial arthropods in vineyards

The intensification of crop management has resulted in a decline of biodiversity in the last decades, in particular through habitat loss, fragmentation and degradation. Semi-natural habitats within agricultural landscapes such as hedges, grasslands or herbaceous field margins, provide resources and refuge to beneficial arthropods. In vineyards, extensively used inter-row vegetation may be functionally equivalent to such semi-natural habitats and sowing of plant species rich in floral resources may improve habitat functions. In this study, three types of vineyard inter-row vegetation treatments were compared in 15 vineyards of South-eastern France: (1) sowing a high-diversity seed mixture (HD) with a high number of nectariferous plant species, (2) spontaneous vegetation, and (3) tilled inter-rows. We monitored the inter-row vegetation including problematic weeds, the abundance of beneficial arthropods, and the predation of sentinel prey. The invasive weedy grass species Cynodon dactylon showed a lower cover in HD inter-rows than in spontaneous vegetation, whereas no differences were found for the invasive herb Erigeron sumatrensis. Both weed species were still best controlled in tilled inter-rows. Beneficial arthropods were less abundant in tilled than in spontaneously vegetated and sown inter-rows. Day predation was higher in HD inter-rows than in spontaneous vegetation although no significant differences were found for observed predators. Over all treatments, plant species richness, flower and grass cover had a positive influence on several beneficial arthropod groups. Our results highlight the positive effects of species-rich inter-row vegetation on weed control, beneficial arthropod abundance and predation but also showed that further research is needed to improve the efficiency beyond services already provided by spontaneous vegetation.

Assessing and Quantifying the Carbon, Nitrogen, and Enzyme Dynamics Effects of Inter-row Cover Cropping on Soils and Apple Tree Development in Orchards

Cover crops between rows in orchards can improve the development of soil resources and increase agricultural productivity. However, there have been few reports of cover crops that can act as a “green manure” in apple orchards across arid and semiarid zones. This study investigated the effects of planting interrow vegetation on soil properties and apple tree performance during a 32-month experiment. There were six treatments: clean cultivation as a control; natural grass planting; planting with ryegrass; planting with alfalfa; planting with tall fescue; and planting with villous wild pea cover crops. The treatments primarily affected the 0- to 20-cm surface soil layer. Soil carbon, nitrogen, and enzyme levels initially decreased (during the first 12–24 months); then, they increased (24–32 months). The cover crops significantly increased nutrient contents (soluble organic carbon, microbial carbon and nitrogen, alkaline dissolved nitrogen, nitrate nitrogen, and ammonium nitrogen) in the 0- to 20-cm soil layer by more than 19.6% and increased the related enzyme activities by more than 25.2%. The alfalfa and wild pea alleys had a stronger effect on the soil environment than the control, natural grass, ryegrass, and tall fescue alley treatments; however, after 32 months, the alfalfa treatment inhibited fruit tree growth and development. This was unexpected because alfalfa seemed to have a positive effect on soil fertility characteristics. Under local ecological conditions, villous wild pea had the greatest effect on apple orchard productivity and significantly increased short branching by 15.9%, fruit weight per fruit by 12.6%, yield per plant by 8.6%, and soluble sugar content by 10.5% compared with clean cultivation. The correlation analysis showed that there were significant or highly significant positive correlations between fruit tree performance and soil carbon, nitrogen, and enzyme activity levels as the soil layer depth increased. Therefore, under local ecological conditions, cover crops have a greater effect on orchard surface soil fertility than on deeper soils, and intercropping with villous wild pea potentially produces the greatest improvement in apple orchard productivity.

Irrigation decreases flower cover and beneficial arthropod abundances in Mediterranean vineyards

Over the last decades, the use of irrigation in vineyards has grown exponentially in response to climate change. In the Mediterranean region, irrigation is the most widely used method of preventing water stress and high sugar content in grapes. However, little is known about potential irrigation effects on biodiversity. This study aims to understand the effect of irrigation on inter-row vegetation, on the abundance of beneficial arthropods and on the predation of pest insects. In the Luberon region of South-Eastern France, nine irrigated and nine non-irrigated vineyards were analysed. Drip irrigation was applied only during the two driest months of the growing season. We found lower flower cover in irrigated vineyards but no difference in species richness and total vegetation cover. Similarly, abundances of several beneficial arthropods were directly affected by irrigation, such as crab spiders, ladybirds, ladybird larvae and parasitic wasps. Structural equation modelling (SEM) revealed that negative irrigation effects on these arthropods were mediated by negative effects on flower cover. Predation rates were also lower in irrigated vineyards but only during daytime. Grapevine yield was not affected by irrigation. Experiments manipulating water availability under controlled conditions may help to understand this surprisingly strong effect of irrigation on flower cover and beneficial arthropod abundance.

Exploring Winegrowers’ Behaviours and Ecological Impacts Under Climate Change and Policy Scenarios—Examples from Three European Winegrowing Regions

Viticulture is an example of a socio-ecological system that poses serious challenges for sustainable soil management and pesticide use, with various interactions between winegrowers’ decision-making and ecological consequences. This study introduces an agent-based model (ABM) on winegrowers’ decision on inter-row management and pesticide use. The ABM builds upon an empirical study of winegrowers’ decision-making in European viticultural landscapes and has been built for three case study regions: Leithaberg (Austria), Palatinate (Germany) and Târnave (Romania). The ABM allows for analysing potential effects of policy instruments including mandatory vegetation cover in the inter-rows, the reduction of fungicide use and ban of insecticides against Lobesia botrana. The effects of policies differ between the case study regions, indicating how important the local context is for effective policies. For example, policies aiming at higher inter-row vegetation cover had the strongest effects on vegetation cover, landscape aesthetics and soil loss in Târnave since many vineyards are currently intensively tilled and there exist no policies supporting inter-row vegetation cover in Romania.

Effect of spontaneous vegetation on beneficial arthropods in Mediterranean vineyards

Habitat destruction and land use intensification are major causes of arthropod decline in agroecosystems. Arthropods are key organisms that are linked to many ecosystem functions and sustainability of agriculture. Using 37 vineyards in Southern France as a model system, we analysed which characteristics of spontaneous inter-row vegetation positively influence beneficial arthropods and pest insect predation. We specifically studied the effects of flower cover, grass cover, the ratio of perennials to annuals, plant species richness and extrafloral nectar on beneficial arthropod communities in vineyards. We used direct observation and net hunting to evaluate arthropod abundance. Sentinel cards with Lucilia sp. larvae were placed on grapevine plants to analyse caterpillar predation. We found that most groups of tested beneficial arthropods were positively influenced by flower cover and plant species richness. In particular, the abundance of predators such as ladybirds (adults and larvae) and crab spiders and the abundance of parasitic wasps were positively correlated to flower cover in vineyard inter-row vegetation. The abundance of ladybirds, hoverflies and crab spiders was also positively related to plant species richness. Our results demonstrated the importance of floral resources and plant diversity for beneficial arthropods and caterpillar predation confirming their key role in biological control of pest insects.

Phytophthora Root Rot in Rangpur Lime Cultivated in Soil Managed with Ecological and Conventional Mower

Root rot and gummosis caused by Phytophthora spp. are considered one of the most important citrus diseases in Brazil. Symptoms of Phytophthora spp. infection in citrus plants are associated with lesions on the bark at the base of the plant, roots, and even lower branches. Inappropriately performed cultural practices, such as excessive irrigation and practices that result in reduced aeration and soil drainage, favor the disease. The objective of this study was to evaluate the effect of Urochloa ruziziensis mulching provided by an ecological mower on the severity of Phytophthora nicotianae root rot and the development of citrus plants and their root system. The experiments were carried out under controlled conditions on Rangpur lime seedlings kept in pots containing soil from ‘Hamlin’ orange orchards with the use of an ecological mower or a conventional mower in the management of inter-row vegetation for six years. Urochloa ruziziensis mulching (9 t ha−1) was added or not to the pots. The inoculation of P. nicotianae in the roots occurred through infection of the soil with a solution containing mycelium and sporangia of the pathogen. A 2 × 2 × 2 factorial scheme was used, with the following factors A: soil type, B: inoculation of P. nicotianae and C: mulching of U. ruziziensis. The attributes of plant development, such as root growth, average number of leaves, leaves and dry mass of shoots and roots, in addition to assessments of the severity of disease in the roots, were evaluated. The mulch of U. ruziziensis did not promote an increase in root rot. The soil resulting from this management promoted the better development of Rangpur lime plants. Therefore, vegetation management of inter-row with an ecological mower is not associated with increased symptoms of Phytophthora root rot.

Cicadomorpha Community (Hemiptera: Auchenorrhyncha) in Portuguese Vineyards with Notes of Potential Vectors of Xylella fastidiosa

Cicadomorpha (Hemiptera) insects are currently responsible for a growing negative impact on the agricultural economy due to their ability to directly damage crops or through the capacity to act as vectors for plant pathogens. The phytopathogenic bacterium Xylella fastidiosa, the causal agent of Pierce's disease in vineyards, is exclusively transmitted by insects of this infraorder. Therefore, knowledge of the Cicadomorpha species and understanding their biology and ecology is crucial. In this work, in 2018 and 2019, the canopy and inter-row vegetation of 35 vineyards distributed in mainland Portugal were sampled to investigate species composition, richness, and diversity of the Cicadomorpha community, with a special focus given to vectors and potential vectors of X. fastidiosa. A total of 11,834 individuals were collected, 3003 in 2018 and 8831 in 2019. Of the 81 species/morphospecies identified, only five are considered vectors or potential vectors of this pathogen, namely, Cicadella viridis (Linnaeus, 1758), Philaenus spumarius (Linnaeus, 1758), Neophilaenus campestris (Fallén, 1805), Lepyronia coleoptrata (Linnaeus, 1758), and N. lineatus (Linnaeus, 1758). Cicadella viridis was the most abundant xylem sap feeder, followed by P. spumarius. In addition, Cicadomorpha that cause direct damage to vines and vectors of grapevine yellows' phytoplasmas were also collected and identified in the sampled vineyards. The results suggested that vectors and potential vectors of X. fastidiosa and a large proportion of the population of Cicadomorpha have a positive correction with inter-row vegetation.

Selection of inter-row herbaceous covers in a sloping, organic, non-irrigated vineyard.

Inter-row vegetation in vineyards is classified as a service crop as it provides many ecosystem services. The vegetation is often removed but maintaining them can mitigate the negative effects on the environment. However, the type of species or mixture choice can affect their success. A field trial was conducted in an organically-managed vineyard of Cabernet sauvignon Vitis vinifera L. cultivars in north-eastern Italy, in which three blends of grass species (Shedonorus arundinaceus, Lolium perenne and Festuca rubra) and two grass-legume mixtures were grown in the inter-rows and compared with resident vegetation and regularly tilled bare soil. Each vegetation type, including resident vegetation, was subjected to mulching and non-mulching treatments. The aim of this study was to evaluate the use of seeded species or mixtures in the inter-row spaces of the vineyard in north-Italy as an alternative management to resident vegetation and tilled soil. The experiment was conducted over two years to monitor the persistence of the sown vegetation and the influence of vegetation types on vine performance and grape composition, and on soil compaction and erosion. The relative abundances of each species, vegetation height, percentage green cover and normalised difference vegetation index (NDVI), vine shoot length, number of leaves per vine shoot, leaf area, bunch weight, vine NDVI, soil compaction and erosion, and depth and width of tractor tyre prints were measured. Over time, weed invasion altered the botanical composition of all vegetation types except for the S. arundinaceus blend, which remained stable throughout the study period. Our results showed that vine parameters were not affected by the type of vegetation in the inter-rows, nor were there differences between the grassed and bare soil inter-rows. Soil compaction and erosion, and tractor tyre prints were not directly affected by the type of vegetation cover, but they were affected by tillage in the plots with bare soil in the inter-rows or where it was used to prepare the soil for sowing. Soil compaction and erosion were related to the percentage vegetation cover. Mulching did not affect any of the parameters measured. Therefore, species selection plays a crucial role in inter-row vegetation management and in minimising environmental impacts. S. arundinaceus gave high protection against soil erosion due to its high persistence throughout the year and had the lowest growth rate thus requiring fewer cuttings.

Use of Remotely Sensed Data for the Evaluation of Inter-Row Cover Intensity in Vineyards

Information on vegetation cover and soil management is used in hydrological and soil erosion modeling, but in most cases, reference values are used solely based on land use classification without considering the actual spatial and temporal variation adopted at the field scale. This work focused on the adoption of satellite optical data from the Copernicus Sentinel-2 (S2) mission to evaluate both spatial and temporal variations of vineyard ground cover. First, on a wider scale, fields were mapped by photointerpretation, and a cluster analysis was carried out. Results suggest that vineyards can be classified according to different inter-row soil management, with the best results obtained using NDVI and NDWI. A pilot area in the municipality of Carpeneto, in the wine-growing area of Alto Monferrato, was also analyzed due to the availability of reference data on inter-row vegetation cover from experimental plots. Those are set on sloping areas and present different inter-row soil managements (conventional tillage—CT, and permanent grass cover—GC). Time series of different vegetation indices (VIs) have been obtained, and both S2 native bands and the derived VIs were evaluated to assess their capability of describing the vineyard’s inter-row coverage growth trends at plot level for the agrarian year 2017–2018. Results suggest that a seasonality effect may be involved in the choice of the most suitable band or index that better describes soil coverage development at a given moment of the year. Further studies on open-source remotely sensed (RS) data could provide specific inputs for applications in erosion risk management and crop modeling.

Species and functional responses of ants to inter-row tillage and vegetation in organic Mediterranean vineyards

Ants are arthropods providing crucial ecosystem services such as soil structuring, nutrient cycling, seed dispersal and pest predation. Thus, their abundance and diversity need to be considered in approaches to improve sustainability of land use such as Mediterranean viticulture. In our study, we tested whether (1) inter-row vegetation and the absence of tillage increase the species richness and/or functional diversity of ants in vineyards and (2) ground cover vegetation drives ant species composition. We included 23 Mediterranean organic vineyards in our analyses and distinguished three types of inter-row management: all inter-rows tilled, half of the inter-rows tilled, and all inter-rows are untilled and covered by vegetation. The occurrence of ant species was analysed in six pitfall traps per vineyard. Around each trap, the floristic composition of inter-row vegetation was analysed in 2 × 2 m² plots. We found that inter-row tillage significantly affected ant species richness, being higher in partially than in fully tilled vineyards whereas untilled vineyards were not different from the other tillage types. Grass cover and the perennial/annual rate were positively correlated with ant species richness. Ant functional diversity and the frequency of most predatory ants were not correlated neither with plant functional groups nor with tillage type. In conclusion, ant communities benefit from inter-row vegetation and/or absence of soil disturbance but partial inter-row tillage of vineyards may be tolerated and even benefit several species. In particular, grasses and perennial plant species favour ants in our system and need to be considered in inter-row sowing.

Population Dynamics of Arthropods in New Caledonian Citrus Orchards

Aims: Agroecological infrastructures are central to the preservation of arthropod populations and ecosystem services associated. There is little data on the population dynamics of New Caledonian citrus orchards. Thus, this study focuses on the response of arthropods to four management methods in the orchard: conventional management, inter-row vegetated, row mulching and edge windbreaks.
 Place and Duration of Study: This study was conducted in the village of La Foa in New Caledonia. It took place over three months, from the end of February to the end of May 2022.
 Methodology: To collect the greatest possible diversity of insects, four complementary trapping methods were used: pitfall traps, yellow plates, Malaise traps and sweeping nets. Once collected, the trapped insects are then sorted and identified. The sorting is done with a binocular magnifying glass. Insects are identified using specific determination keys, documentation, or with the help of the Reference Collection of Terrestrial Invertebrates of New Caledonia - Xavier Montrouzier (CXMNC). When identification is not immediately possible, a morphotype number is assigned. For each species and morphospecies, a photograph is taken. Alpha and beta diversity was studied using rarefactions, Shannon index and Generalized Linear Models.
 Results: A positive effect of agroecological infrastructures on insects’ abundance and diversity was recorded. In contrast, low arthropod abundances and diversities were presented in the orchard under conventional management (P < 0.001). Mulching management was the parameter showing the much higher insects’ abundance. Moreover, populations dynamics were generally correlated with the related infrastructures. Thus, windbreaks acted as ecological corridors and the inter-row vegetation as refuge habitats for beneficial insects. 
 Conclusion: These results demonstrate the damage of conventional agriculture on arthropod diversity in New Caledonian orchards. They also show that agroecological infrastructures can bring back insect biodiversity, especially with the mulching management.

Edaphoclimatic drivers of the effect of extensive vegetation management on ecosystem services and biodiversity in vineyards

Vineyards are a very important perennial woody crop globally, but they are also among the most intensively managed agroecosystems. This has resulted in biologically impoverished and highly eroded vineyards. Environmentally-friendly inter-row vegetation management, particularly the use of cover crops, could contribute to avoid erosion and regenerate soil biodiversity in vineyards. In this study, we updated a global meta-analysis on the effects of inter-row extensive vegetation cover management, particularly through the use of cover crops, on ecosystem services, including supporting, regulating and provisioning services, and biodiversity in vineyards. We also analyzed the role of environmental variables (climate, including precipitation- and temperature-related bioclimatic variables and soil properties, including pH and texture) and irrigation in modulating these effects. The presence of extensive vegetation cover consistently increased biodiversity, as well as supporting ecosystem services in irrigated vineyards and regulating services in rainfed vineyards. Provisioning services, which were evaluated as grape yield, were slightly negatively affected in rainfed vineyards, but not in irrigated ones. The effects of vegetation cover on ecosystem services varied depending on the climate and edaphic characteristics of vineyards. For example, supporting ecosystem services were favored in acidic soils and were also positively related to the precipitation of the wettest quarter, whereas regulating services were particularly enhanced in alkaline soils and in locations with lower temperatures of the wettest quarter. Biodiversity was especially favored in locations with lower precipitation seasonality. Taken together, our study indicates the importance of developing strategies for the adaptive management of extensive vegetation covers tailored to the climatic and edaphic conditions of each vineyard. This adaptive management, combined with irrigation and potentially other locally-tailored adaptive strategies, could also contribute to further mitigate potential negative effects of vegetation cover on grape production while maximizing other ecosystem services such as provisioning and supporting services and biodiversity.

General trends of different inter-row vegetation management affecting vine vigor and grape quality across European vineyards

Cover crops in vineyards do provide many important ecosystem functions, however wine growers are often reluctant to incorporate cover crops into their vineyard management as they are concerned about competition regarding water and nutrient availability. The objective of this study was to define the effects of three standard inter-row vegetation management strategies on vine growth and grape quality in different European regions. We hypothesize that general patterns of responses to different inter-row management can be identified across European vine growing regions independent of local climate and soil conditions. Data were collected in 2016 and 2017 in commercial vineyards located in five European temperate wine growing regions directly comparing standard inter-row vegetation management strategies in parallel in vineyards ranging from cover crops to bare ground through tillage or herbicide application. Vegetation management strongly influenced leaf chlorophyll content, shoot pruning weight and yeast assimilable nitrogen (YAN) in grape juice. Across countries, grape varieties and varying soil conditions, YAN consistently showed higher values in grapes separated by bare ground inter-rows as compared to inter-rows with a permanent vegetation cover. Other grape quality parameters, total soluble solids, total titratable acidity and berry weight were not or inconsistently affected across countries, preventing the prediction of generalized trends. We also observed higher values of soil organic matter in complete vegetation inter-rows. In conclusion, we identified general effects of inter-row vegetation management on vine vigor and grape quality across countries and grape varieties in different pedo-climatic conditions. Our study provides general response patterns as a basis for functional studies to develop local inter-row vegetation management strategies.

Vegetation increases abundances of ground and canopy arthropods in Mediterranean vineyards

The decline of arthropod populations observed in many parts of the world is a major component of the sixth mass extinction with intensive agriculture being one of its main drivers. Biodiversity-friendly farming practices are taking centre stage in the recovery process. In vineyards, vegetation cover is commonly used for production purposes, to reduce soil compaction by machinery use and soil erosion. Here we examined the effects of vegetation cover and soil management on the abundance of ground- (spiders, beetles, Hemiptera and harvestmen) and canopy-dwelling (wild bees, green lacewings, beetles and Hemiptera) arthropods in three categories of vineyards: (i) vineyards with no vegetation, (ii) partially vegetated (every second inter-row is vegetated) and (iii) all inter-rows are vegetated. We recorded a general positive effect of a decrease in soil perturbation intensity and corresponding higher vegetation cover on arthropod abundance. Plant species richness was the most important vegetation parameter, with a positive effect on spiders, harvestmen, hemipterans and beetles (ground and canopy) abundances. Using a path analysis, we also highlighted the central role of inter-row vegetation management in trophic and non-trophic relationships between vegetation and arthropods, and between arthropod groups. Our results demonstrate the benefits of a softer soil management preserving a diverse vegetation cover for the conservation of arthropods in Mediterranean vineyards.

The impact of vineyard inter-row vegetation on plant and insect diversity

The impact of vineyard inter-row vegetation on plant and insect diversity

The Effect of the Proportion of Adjacent Non-Crop Vegetation on Plant and Invertebrate Diversity in the Vineyards of the South Moravian Region

Increasing vulnerability of crops to pests and diseases, problems with soil erosion, a decline in biodiversity and a number of other negative impacts caused by agricultural intensification and monocultural production have been the subjects of many studies in recent decades. Today, cover cropping has become a promising practice to defuse these negative impacts, and it is emerging in many wine-producing regions, including the Czech Republic. However, the importance of permanent natural and semi-natural habitats in agricultural production should not be neglected. In this study, the effect of adjacent non-crop vegetation on plant and insect diversity was evaluated. The highest plant species richness of inter-row vegetation was found in vineyards with a high proportion (>40%) of non-crop vegetation within a 500-m radius. Regarding the agricultural impact of inter-row vegetation, the high proportion of non-crop vegetation could have been related to the higher presence of opportunistic and non-harmful weeds, compared with the presence of dangerous weed species. The number of insect families present in inter-rows was probably affected more by the vegetation coverage rate than by the proportion of adjacent non-crop vegetation. However, the occurrence of the Hymenoptera species, often representing beneficial organisms, was related to localities with a high proportion of adjacent non-crop vegetation.

Biodiversity effects on grape quality depend on variety and management intensity.

Interactions between plants can be beneficial, detrimental or neutral. In agricultural systems, competition between crop and spontaneous vegetation is a major concern. We evaluated the relative support for three non‐exclusive ecological hypotheses about interactions between crop and spontaneous plants based on competition, complementarity or facilitation.The study was conducted in Swiss vineyards with different vegetation management intensities. In all, 33 vineyards planted with two different grape varieties were studied over 3 years to determine whether low‐intensity vegetation management might provide benefits for grape quality parameters. Management intensity varied with the degree of control of spontaneous inter‐row vegetation. Features of spontaneous vegetation measured included total cover, total species richness and abundance of nitrogen‐fixing plants. Grape quality parameters of known importance to wine making (yeast assimilable nitrogen, sugars, tartaric acid and malic acid) were determined by Fourier‐transform infrared spectroscopy (FTIR). Using structural equation modelling, we evaluated hypotheses about the multivariate responses of grape quality parameters as well as the direct and indirect (plant‐mediated) effects of management.Observed effects of management differed between grape varieties. Management intensity and abundance of N‐fixing plants significantly influenced grape quality parameters while total richness of spontaneous plants did not have detectable effects. Abundance of N‐fixing plants was enhanced by low‐intensity management resulting in increased N content in the red grape variety Pinot noir, potentially enhancing grape quality, while measured soil N content did not explain the increase.Synthesis and applications. Our study shows that crop quality can be enhanced by spontaneous plants, in this case by the abundance of a key functional group (N‐fixers), most likely through plant–plant or plant–microbe facilitation. However, beneficial interactions may have a high specificity in terms of facilitation partners and may have contrasting effects at low taxonomic resolutions such as crop varieties. Generally, increasing plant biodiversity in agricultural systems may increase competition with crops. Thus, the identification of suitable interaction partners and a careful balance between crop variety and spontaneous plant species may be necessary to utilize beneficial interactions and to reduce the trade‐off between agricultural production and biodiversity to achieve a sustainable ecological benefit in agricultural systems.

Enhancing flowering plant functional richness improves wild bee diversity in vineyard inter-rows in different floral kingdoms.

Wild bees are threatened by multiple interacting stressors, such as habitat loss, land use change, parasites, and pathogens. However, vineyards with vegetated inter‐rows can offer high floral resources within viticultural landscapes and provide foraging and nesting habitats for wild bees. Here, we assess how vineyard management regimes (organic vs. conventional; inter‐row vegetation management) and landscape composition determine the inter‐row plant and wild bee assemblages, as well as how these variables relate to functional traits in 24 Austrian and 10 South African vineyards. Vineyards had either permanent vegetation cover in untilled inter‐rows or temporary vegetation cover in infrequently tilled inter‐rows. Proportion of seminatural habitats (e.g., fallows, grassland, field margins) and woody structures (e.g., woodlots, single trees, tree rows) were used as proxies for landscape composition and mapped within 500‐m radius around the study vineyards. Organic vineyard management increased functional richness (FRic) of wild bees and flowering plants, with woody structures marginally increasing species richness and FRic of wild bees. Wild bee and floral traits were differently associated across the countries. In Austria, several bee traits (e.g., lecty, pollen collection type, proboscis length) were associated with flower color and symmetry, while in South African vineyards, only bees’ proboscis length was positively correlated with floral traits characteristic of Asteraceae flowers (e.g., ray–disk morphology, yellow colors). Solitary bee species in Austria benefitted from infrequent tillage, while ground nesting species preferred inter‐rows with undisturbed soils. Higher proportions of woody structures in surrounding landscapes resulted in less solitary and corbiculate bees in Austria, but more aboveground nesting species in South Africa. In both countries, associations between FRic of wild bees and flowering plants were positive both in organic and in conventional vineyards. We recommend the use of diverse cover crop seed mixtures to enhance plant flowering diversity in inter‐rows, to increase wild bee richness in viticultural landscapes.

Organic Farming and Cover-Crop Management Reduce Pest Predation in Austrian Vineyards.

Simple SummaryGlobal declines in arthropods necessitate a rethinking of current agricultural practices. Organic farming, complex landscapes with high proportions of seminatural habitats and local vineyard management practices such as implementation of flower-rich cover-crop mixtures may be a promising approach to enhance arthropod biodiversity and, thus, natural pest control in viticulture. We examined effects of organic farming, different types of vineyard inter-row vegetation, and landscape composition on natural pest control of a major grapevine pest, the grape berry moth Lobesia botrana, and identified its dominant natural enemies. Surprisingly, natural pest control was reduced by sown cover-crops and organic farming. Interestingly, bush crickets were one of the most dominant natural enemies in the Austrian study region. Negative effects of organic farming in our study are most likely related to high fungicide inputs. Thus, a promising approach to reduce fungicide input and, therefore, promote a more sustainable viticulture may be the implementation of fungus-resistant grape varieties.Habitat simplification and intensive use of pesticides are main drivers of global arthropod declines and are, thus, decreasing natural pest control. Organic farming, complex landscapes, and local vineyard management practices such as implementation of flower-rich cover-crop mixtures may be a promising approach to enhance predator abundance and, therefore, natural pest control. We examined the effect of organic versus integrated management, cover-crop diversity in the vineyard inter-rows, and landscape composition on the natural pest control of Lobesia botrana eggs and pupae. Predation of L. botrana pupae was reduced by organic farming and species-poor cover-crops by about 10%. Predation rates of L. botrana eggs did not differ significantly in any of the studied management options. Dominant predators were earwigs (Forficulidae), bush crickets (Tettigoniidae), and ants (Formicidae). Negative effects of organic viticulture are most likely related to the negative nontarget effects on arthropods related to the frequent sulfur and copper applications in combination with the avoidance of strongly damaging insecticides by integrated winegrowers. While a 10% difference in predation rates on a single pest stage is unlikely to have strong practical implications, our results show that the assumed effectiveness of environmentally friendly agriculture needs to be evaluated for specific crops and regions.

The key role of inter-row vegetation and ants on predation in Mediterranean organic vineyards

Biodiversity-friendly farming practices are taking centre stage, with herbicide use sparking major public debate on human health. Vegetation cover is increasingly used to enhance agroecosystem biodiversity and functions, providing important ecosystem services like biological pest control. However, further information is required on the relationship between vegetation cover, natural enemies, and pest predation. Using a sentinel prey experiment set up in 26 Mediterranean organic vineyards, we analysed the response of generalist predators, and the associated final predation and dynamics under three inter-row management types: bare soil, one out of two inter-rows vegetated and all inter-rows vegetated. Predation on sentinel prey was monitored on the ground and on the vine trunk throughout the daytime and after a night of exposure. Generalist predator abundance was quantified using pitfall traps. Final sentinel prey predation both on vine trunks and on the ground were significantly higher in fully vegetated vineyards, with a shorter prey survival time than in tilled vineyards. Both diurnal and nocturnal predation were significantly related to increased vegetation cover and richness. Moreover, 96 % of the identified predation events involved ants. We demonstrated the key role of vegetation cover in improving the predation function through a spill-over from the inter-row to the grapevine. Contrary to what is commonly observed in agrosystems, we clearly identified ants as the predominant predator both on the ground and on the vine trunk. Our study has important implications for Mediterranean vineyard management, promoting vegetation as a nature-based solution. Sustainable management of vineyard vegetation favouring the natural predator community may contribute to a reduction in pesticide use and fossil fuel consumption.