How do hedgerow characteristics alter the dispersal of Pseudocercospora fijiensis propagules?

BACKGROUND

Hedgerows represent an agroecological lever for pest management. To date, few studies have shown that they can be used as a lever for the control of aerial fungal diseases, especially as a barrier to dispersal. On banana production, the main disease is black leaf streak disease (BLSD), which is a fungal disease caused by Pseudocercospora fijiensis. This pathogen disperses through two types of spores: ascospore and conidia. The aim of this study was to observe and to quantify the effect of hedgerows on BLSD dispersal. Trap plants were placed at the same distance to an artificial source of inoculum with a hedgerow on one side. Lesions were counted to establish the daily lesion density of each trap plant. The combination of hedgerow characteristics such as height, width, and optical porosity were used to evaluate its potential capacity to intercept spores.

RESULTS

When ascospores were used as a source of inoculum, the lesion density on traps plant decreased up to 50% between the hedgerow with the lowest interception capacities and the one with the highest interception capacities. For conidia, hedgerow height and side of the trap plants (with or without hedgerow between them and the source) were not significant, but low porosity of the hedgerow reduced the lesion density. On the contrary, for ascospore, the hedgerow effect was anisotropic; the trap plants on hedgerow side had less lesions.

CONCLUSION

Our study is the first experimental proof of the effect of hedgerows on P. fijiensis dispersion, both on conidia and ascospore. We showed that hedgerow characteristics impact the capacity of interception of the hedgerow. © 2023 Society of Chemical Industry.

Discrepancies between the drivers of alpha and beta plant diversity in arable field margins

Field margins are major habitats for biodiversity conservation and ecosystem functioning in agricultural landscapes, but biotic homogenization of plant communities threatens their ecological and agronomic functions. Our objective is to determine the drivers of plant diversity in field margins for conservation and restoration purposes. To do so, we assessed the effects of field margin structure and long-term management over 20 years (1995-2015) on the taxonomic and functional α- and β-diversity, and the functional composition of herbaceous plant communities. In 2015, we surveyed 302 field margins in bocage landscapes of Brittany, northwestern France. Results were very similar between taxonomic and functional diversity but revealed important discrepancies between the drivers of α- and β-diversity. Deep ditches, mowing and grazing increased α-diversity but did not affect β-diversity. Denser hedgerows had lower α-diversity than other field margins but strongly contributed to β-diversity by harbouring more unique sets of species or life strategies. Long-term herbicide spraying in field margins and cropping intensity in adjacent habitats did not affect α-diversity, but had more complex effects on β-diversity and selected for common weeds. All in all, preservation of dense hedgerows, abandonment of herbicide spraying, and protection against agrochemical drifts are key measures to prevent the establishment of common weeds and biotic homogenization of herbaceous plant communities in field margins. Above all, our study shows how important it is to go beyond α-diversity to make robust conservation and restoration decisions.

Effects of Different Hedgerow Patterns on the Soil Physicochemical Properties, Erodibility, and Fractal Characteristics of Slope Farmland in the Miyun Reservoir Area

Soil erosion of sloping farmland in the Miyun reservoir area in Beijing has become a serious issue and has threatened the ecological environment and safety of the reservoir area. We used the Taishizhuang Village Non-point Source Pollution Prevention & Control Base in the Miyun reservoir as a study area and performed a comparative analysis of the physicochemical properties of soil of the upper, middle, and lower slopes of the Scutellaria baicalensis + Buchloe dactyloides plot (Treatment 1, T1), Morus alba + Buchloe dactyloides plot (Treatment 2, T2), Salvia miltiorrhiza + Cynodon dactylon plot (Treatment 3, T3), Platycodon grandiflorus + Cynodon dactylon plot (T4), and a barren land control plot (Control check, CK), to explore how different hedgerow patterns affect the soil’s physicochemical properties, anti-erodibility, and fractal characteristics. We found the following: (1) The primary soil mechanical composition included sand particles in the upper slopes, whereas it was soil fine particles in the middle and lower slopes. (2) The fractal dimension of the slope soil showed a significant negative correlation with sand particles (R2 = 0.9791) while being positively correlated with silt particles (R2 = 0.9635) and clay particles (R2 = 0.9408). (3) All hedgerow patterns increased soil nutrients, with the Morus alba + Buchloe dactyloides hedgerow plot increasing the soil total nitrogen (STN), soil total phosphorus (STP), and soil organic matter (SOM) content by 213.89−282.69%, 55.56−58.15%, and 29.77−56.04%, respectively. (4) The Morus alba + Buchloe dactyloides hedgerow plot significantly decreased the soil erodibility factor K value, improved soil anti-erodibility, and reduced soil erosion. (5) The K value of the soil erodibility was significantly negatively correlated with clay particles, soil fractal dimension, and STP (p < 0.01); positively correlated with sand particles; and negatively correlated with silt particles, STN, and SOM. Therefore, the Morus alba + Buchloe dactyloides hedgerow planting contributes to clay particle conservation, soil nutrient content improvement, soil structure optimization, and soil anti-erodibility enhancement.

Native Flowering Border Crops Attract High Pollinator Abundance and Diversity, Providing Growers the Opportunity to Enhance Pollination Services

Over the past century, habitat loss from agricultural intensification has contributed to pollinator decline. One way to mitigate the harmful effects of agricultural intensification is through the re-introduction of native flowering plants as border strips that provide supplemental floral and nesting resources to pollinators. However, border crop species vary in bloom period and flower densities, and are thus likely to attract different suites of pollinator species. Resulting differences in pollinator community composition are likely to affect their ability to provide pollination services to adjacent crop habitat. To address these issues, we implemented a two-year study on the impact of different flowering border crops on pollinator abundance, richness, and community composition. We also examined which crop features (bloom duration, number of flowers, floral area) were most likely to affect pollinator densities. We found that native flowering plant border crops of diverse prairie mix and monocultures of silflower (Silphium integrifolium Michx.) and cup plant (Silphium perfoliatum L.) attracted the highest abundance and species richness of bees and pollinator groups combined, while alfalfa (Medicago sativa L.) attracted the highest lepidopteran abundance and species richness. We also found a significant, positive relationship between pollinator abundance and floral resource amount and bloom duration. These findings offer valuable insight into the impacts of different land management strategies on different pollinator groups, and thus provide landowners with management options for attracting specific pollinator groups and species.

Mass-flowering monoculture attracts bees, amplifying parasite prevalence

As the global agricultural footprint expands, it is increasingly important to address the link between the resource pulses characteristic of monoculture farming and wildlife epidemiology. To understand how mass-flowering crops impact host communities and subsequently amplify or dilute parasitism, we surveyed wild and managed bees in a monoculture landscape with varying degrees of floral diversification. We screened 1509 bees from 16 genera in sunflower fields and in non-crop flowering habitat across 200 km² of the California Central Valley. We found that mass-flowering crops increase bee abundance. Wild bee abundance was subsequently associated with higher parasite presence, but only in sites with a low abundance of non-crop flowers. Bee traits related to higher dispersal ability (body size) and diet breadth (pollen lecty) were also positively related to parasite presence. Our results highlight the importance of non-crop flowering habitat for supporting bee communities. We suggest monoculture alone cannot support healthy bees.

Over-Winter Survival and Nest Site Selection of the West-European Hedgehog (Erinaceus europaeus) in Arable Dominated Landscapes

The West-European hedgehog (Erinaceus europaeus) has declined markedly in the UK. The winter hibernation period may make hedgehogs vulnerable to anthropogenic habitat and climate changes. Therefore, we studied two contrasting populations in England to examine patterns of winter nest use, body mass changes and survival during hibernation. No between-site differences were evident in body mass prior to hibernation nor the number of winter nests used, but significant differences in overwinter mass change and survival were observed. Mass change did not, however, affect survival rates; all deaths occurred prior to or after the hibernation period, mainly from predation or vehicle collisions. Hedgehogs consistently nested in proximity to hedgerows, roads and woodlands, but avoided pasture fields; differences between sites were evident for the selection for or avoidance of arable fields, amenity grassland and buildings. Collectively, these data indicate that hibernation was not a period of significant mortality for individuals that had attained sufficient weight (>600 g) pre-hibernation. Conversely, habitat composition did significantly affect the positioning of winter nests, such that different land management practices (historic and current) might potentially influence hibernation success. The limitations of this study and suggestions for future research are discussed.

Ground Beetle (Coleoptera: Carabidae) Assemblages and Slug Abundance in Agricultural Fields Under Organic and Low-Input Conventional Management Within a Long-Term Agronomic Trial in Central Italy

Inside a long-term agronomic trial aimed at evaluating the effects of organic and low-input conventional management systems on soil fertility and arable crop production, we selected six fields bordered by hedgerows, three under each management system. Here, we analyzed the carabid assemblages and the slug abundance. Samplings took place in five different periods, across 1 yr of observations. The carabid abundances were similar in organic and conventional fields. The Shannon-Wiener diversity index (H') showed a higher value in the conventional fields, although in the organic fields, a higher number of species were observed. The multivariate analysis described similar carabid communities, but excluding the period factor, it showed a significant influence of the management system. There was no difference between the captures of traps placed along the hedgerow and in the middle, whereas in the conventional fields, the hedgerow traps captured a higher number of specimens, showing a role of the hedgerow as carabid reservoir. The slugs were present mainly while green manure was grown on the organic fields where also Poecilus cupreus Linné, 1758 (Coleoptera: Carabidae) was captured abundantly.

Trapping Brown Marmorated Stink Bugs: "The Nazgȗl" Lure and Kill Nets

Improvements to current brown marmorated stink bug (BMSB), Halyomorpha halys, surveillance and killing systems are needed to improve detection sensitivity and to reduce pesticide use. Detection of BMSB in New Zealand with traps is reliant on sticky panels with aggregation pheromone, which are low cost but inefficient compared with beating foliage. Trapping for BMSB adults and nymphs was conducted daily with lethal traps consisting of an aggregation pheromone-baited-coat hanger covered with dark-colored long-lasting insecticide-treated mesh, we termed “The Nazgȗl”, based on its sinister appearance. A deep tray lined with white plastic was attached centrally at the base for collecting the dead BMSB. The lethal traps killed and caught up to 3.5-fold more nymphs and adult BMSB than identically-baited sticky panels in the 3 weeks of deployment, and provided a snapshot of phenology by instar. We expect that lure-and-kill stations could contribute to the suppression of a delimited population and could be included as part of a semiochemical-based eradication program. Attracting and killing females and nymphs, thus removing future offspring, could contribute to population suppression during an eradication.

Proximity of restored hedgerows interacts with local floral diversity and species' traits to shape long-term pollinator metacommunity dynamics

Disconnected habitat fragments are poor at supporting population and community persistence; restoration ecologists, therefore, advocate for the establishment of habitat networks across landscapes. Few empirical studies, however, have considered how networks of restored habitat patches affect metacommunity dynamics. Here, using a 10-year study on restored hedgerows and unrestored field margins within an intensive agricultural landscape, we integrate occupancy modelling with network theory to examine the interaction between local and landscape characteristics, habitat selection and dispersal in shaping pollinator metacommunity dynamics. We show that surrounding hedgerows and remnant habitat patches interact with the local floral diversity, bee diet breadth and bee body size to influence site occupancy, via colonisation and persistence dynamics. Florally diverse sites and generalist, small-bodied species are most important for maintaining metacommunity connectivity. By providing the first in-depth assessment of how a network of restored habitat influences long-term population dynamics, we confirm the conservation benefit of hedgerows for pollinator populations and demonstrate the importance of restoring and maintaining habitat networks within an inhospitable matrix.

Spray particle drift mitigation using field corn (Zea mays L.) as a drift barrier

BACKGROUND

Herbicide particle drift reduces application efficacy and can cause severe impacts on nearby vegetation depending on the herbicide mode of action, exposure level, and tolerance to the herbicide. A particle drift mitigation effort placing windbreaks or barriers on the field boundaries to reduce off-target movement of spray particles has been utilized in the past. The objective of this research was to evaluate the effectiveness of field corn (Zea mays L.) at different heights as a particle drift barrier.

RESULTS

Applications with a non-air inclusion flat fan nozzle (ER11004) resulted in greater particle drift when compared with an air inclusion nozzle (TTI11004). Eight rows of corn were used as barriers (0.91, 1.22, and 1.98 m height) which reduced the particle drift for both nozzles, especially at shorter downwind distances. Applications with the ER11004 nozzle without corn barriers had 1% of the applied rate (D99 ) predicted to deposit at 14.8 m downwind, whereas this distance was reduced (up to 7-fold) when applications were performed with corn barriers. The combination of corn drift barriers and nozzle selection (TTI11004) provided satisfactory particle drift reduction when the D99 estimates were compared with those for applications with the ER11004 nozzle without corn barriers (up to 10-fold difference).

CONCLUSION

The corn drift barriers were effective in reducing particle drift from applications with the ER11004 and the TTI11004 nozzles (Fine and Ultra Coarse spray classifications, respectively). The corn drift barrier had appropriate porosity and width as the airborne spray was captured within its canopy instead of deflecting up and over it. © 2018 Society of Chemical Industry.

Impact of Agroecological Infrastructures on the Dynamics of Dysaphis plantaginea (Hemiptera: Aphididae) and Its Natural Enemies in Apple Orchards in Northwestern France

Apple orchard production is facing new environmental and societal challenges, resulting, in particular, in strong pressure to reduce pesticide use. Cider-apple production, for which the perfect visual aspect of fruits is not a marketability imperative, offers good opportunities to study production systems that are developing new agronomic strategies, which could be subsequently extended to all apple-production types. Agroecological infrastructures play an important role in providing shelter, food resources, or reproduction habitats to many arthropods. Consequently, setting-up agroecological infrastructures in the vicinity of or within orchards could increase natural enemy presence and thus improve the biological control of pests. In this study, we focused on Dysaphis plantaginea (Passerini), one of the major pests in apple orchards in Europe, which causes important economic production losses. During two years (2014 and 2015), we monitored the population dynamics of D. plantaginea, its natural enemies, and mutualistic ants in commercial production cider-apple orchards. The influences of the cider-apple cultivar, insecticide use, and distance to agroecological infrastructures (hedgerows and flower strips) were assessed. Our results suggest that flower strips favor an increase in natural enemy abundance in the vicinity of the orchards and could thus play an important role in the production system by improving the biological control of D. plantaginea.

Pest Control and Pollination Cost-Benefit Analysis of Hedgerow Restoration in a Simplified Agricultural Landscape

Field edge habitat in homogeneous agricultural landscapes can serve multiple purposes including enhanced biodiversity, water quality protection, and habitat for beneficial insects, such as native bees and natural enemies. Despite this ecosystem service value, adoption of field border plantings, such as hedgerows, on large-scale mono-cropped farms is minimal. With profits primarily driving agricultural production, a major challenge affecting hedgerow plantings is linked to establishment costs and the lack of clear economic benefits on the restoration investment. Our study documented that hedgerows are economically viable to growers by enhancing beneficial insects and natural pest control and pollination on farms. With pest control alone, our model shows that it would take 16 yr to break even from insecticide savings on the US$4,000 cost of a typical 300-m hedgerow field edge planting. By adding in pollination benefits by native bees, where honey bees ( Apis mellifera L.) may be limiting, the return time is reduced to 7 yr. USDA cost share programs allow for a quicker return on a hedgerow investment. Our study shows that over time, small-scale restoration can be profitable, helping to overcome the barrier of cost associated with field edge habitat restoration on farms.

Landfill restoration and biodiversity: a case of study in Northern Italy

Landfilling is a worldwide common waste treatment method. Final recovery usually consists of capping the area with top soil on which vegetation can grow. Depending on the suitability of the recovery pattern, landfill sites can work as potential reserve of semi-natural habitats. A recovery pattern applied to land reclamation of two hazardous waste landfills sited in Northern Italy (Po floodplain) was studied to assess the results in terms of biodiversity. These landfills lie within a landscape dominated by intensive agriculture. After final sealing, both landfills were covered by soil on which a meadow was sown and a hedgerow was planted around the borders. One of the compared areas was not provided with a pond and the hedgerow was incomplete. Butterflies and birds were used as indicators, and their seasonal abundance was related to habitat structure and ecological factors. Meadows grown on both areas supported a rich butterfly population (30 species), including some species that are by now uncommon in the Po floodplain. In both areas butterfly abundance was affected by summer drought. The birds' community included 57 species; 16 Species of European Conservation Concern (SPECs) were observed. Each bird community was different in the compared study areas because of their different size and habitat structure. For example, landfill A, provided with a pond and a more complex structure of the hedgerow, supported a richer birds community (52 species versus 39). Both restored landfills worked well as a stepping stone for migratory birds, but they were a reproductive habitat of poor quality.

The spatial distribution of the Japanese beetle, Popillia japonica, in soybean fields

The Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), is a serious pest of many agricultural and horticultural plants. Relatively little research has investigated the distributions of Japanese beetles in agricultural fields, and this lack of information makes pest management more difficult. In the present study, the spatial distribution of Japanese beetles in soybean fields was examined. Specifically, how the distribution and abundance of beetles was affected by distance from an edge, edge direction, and edge type was examined. An edge effect for density was discovered; beetle numbers decreased significantly with increasing distance from the field edge. The east and south sides averaged higher numbers of beetles than the north and west. Downwind edges, in particular downwind edges adjacent to hedgerows, also had significantly higher beetle densities. In addition, females relatively far from the edge had larger egg loads than those closer to the edge. Differences in aggregation seeking behavior, in combination with movement in relation to wind and obstructions such as hedgerows, are possible explanations for these spatial patterns.