Windbreaks as a pesticide drift mitigation strategy: a review

Enhancing knowledge of chemical exposures and fate in honey bee hives: Insights from colony structure and interactions

Honey bees are unintentionally exposed to a wide range of chemicals through various routes in their natural environment, yet research on the cumulative effects of multi-chemical and sublethal exposures on important caste members, including the queen bee and brood, is still in its infancy. The hive's social structure and food-sharing (trophallaxis) practices are important aspects to consider when identifying primary and secondary exposure pathways for residential hive members and possible chemical reservoirs within the colony. Secondary exposures may also occur through chemical transfer (maternal offloading) to the brood and by contact through possible chemical diffusion from wax cells to all hive members. The lack of research on peer-to-peer exposures to contaminants and their metabolites may be in part due to the limitations in sensitive analytical techniques for monitoring chemical fate and dispersion. Combined application of automated honey bee monitoring and modern chemical trace analysis techniques could offer rapid progress in quantifying chemical transfer and accumulation within the hive environment and developing effective mitigation strategies for toxic chemical co-exposures. To enhance the understanding of chemical fate and toxicity within the entire colony, it is crucial to consider both the intricate interactions among hive members and the potential synergistic effects arising from combinations of chemical and their metabolites.

Chemical ecology of Himalayan eggplant variety's antixenosis: identification of geraniol as an oviposition deterrent against the eggplant shoot and fruit borer

Eggplant (Solanum melongena) suffers severe losses due to a multi-insecticide-resistant lepidopteran pest, shoot and fruit borer (SFB, Leucinodes orbonalis). Heavy and combinatorial application of pesticides for SFB control renders eggplant risky for human consumption. We observed that gravid SFB females do not oviposit on Himalayan eggplant variety RC-RL-22 (RL22). We hypothesized that RL22 contained an antixenosis factor. Females' behavior indicated that the RL22 cue they perceived was olfactory. To identify it, leaf volatile blends of seven eggplant varieties were profiled using solid phase microextraction and gas chromatography mass spectrometry. Seven RL22-specific compounds were detected in the plant headspace. In choice assays, oviposition deterrence efficacies of these candidate compounds were independently tested by their foliar application on SFB-susceptible varieties. Complementation of geraniol, which was exclusively found in RL22, reduced oviposition (> 90%). To validate geraniol's role in RL22's SFB-deterrence, we characterized RL22's geraniol synthase and silenced its gene in planta, using virus-induced gene silencing. Geraniol biosynthesis suppression rendered RL22 SFB-susceptible; foliar geraniol application on the geraniol synthase-silenced plants restored oviposition deterrence. We infer that geraniol is RL22's SFB oviposition deterrent. The use of natural compounds like geraniol, which influence the chemical ecology of oviposition, can reduce the load of hazardous synthetic larvicides.

Monitoring and risk analysis of residual pesticides drifted by unmanned aerial spraying

This study aimed to investigate the residual characteristics of pesticides drifted by unmanned aerial spray according to buffer strip, windbreak, and morphological characteristics of non-target crops, suggest prevention for drift reduction, and finally conduct a risk analysis on pesticides exceeding the maximum residue limit (MRL) or uniform level (0.01 mg/kg) of the positive list system (PLS). Non-target crops were collected around the aerial sprayed area (paddy rice) in Boryeong, Seocheon, and Pyeongtaek after UAV spray. When pesticides were detected in more than three samples, Duncan's multiple range test was performed. In cases where pesticides were detected in only two samples, an independent sample t-test was conducted (p < 0.05). The drift rate of pesticides tends to decrease by up to 100% as the buffer distance from aerial sprayed area increases or when a windbreak, such as maize, is present between two locations. Thus, the reduction of drifted pesticides could be effective if both factors were applied near the UAV spray area. Moreover, the residue of drifted pesticides was found to be the highest in leafy vegetables such as perilla leaves or leaf and stem vegetables such as Welsh onion, followed by fruit vegetables and cucurbits, owing to the morphological characteristics of crops. Therefore, selecting pulse or cereal such as soybean or maize as a farm product near the UAV spray area can be considered to minimize the drift. For pesticides that exceed the MRL or PLS uniform level, %acceptable dietary intake is 0-0.81% with no risk. Additionally, employing pesticides approved for both paddy rice and farm products in UAV spraying can effectively minimize instances where MRL or PLS are exceeded. Therefore, this study aims to provide farmers with effective guidelines for mitigating drift. Furthermore, we strive to promote stable and uninterrupted food production while facilitating the utilization of agricultural technologies such as UAV spraying to address labor shortages and ensure sustainable food security.

Structure, Functionality, Compatibility with Pesticides and Beneficial Microbes, and Potential Applications of a New Delivery System Based on Ink-Jet Technology

Accurate application of agrochemicals is an important way to achieve efficient use of chemicals and to combine limited pollution with effective control of weeds, pests, and diseases. In this context, we investigate the potential application of a new delivery system based on ink-jet technology. First, we describe the structure and functionality of ink-jet technology for agrochemical delivery. We then evaluate the compatibility of ink-jet technology with a range of pesticides (four herbicides, eight fungicides, and eight insecticides) and beneficial microbes, including fungi and bacteria. Finally, we investigated the feasibility of using ink-jet technology in a microgreens production system. The ink-jet technology was compatible with herbicides, fungicides, insecticides, and beneficial microbes that remained functional after passing through the system. In addition, ink-jet technology demonstrated higher area performance compared to standard nozzles under laboratory conditions. Finally, the application of ink-jet technology to microgreens, which are characterized by small plants, was successful and opened the possibility of full automation of the pesticide application system. The ink-jet system proved to be compatible with the main classes of agrochemicals and showed significant potential for application in protected cropping systems.

Particle drift simulation from mesotrione and rimsulfuron plus thifensulfuron-methyl mixture through two nozzle types to field and vegetable crops

Potential for off-target movements follows every herbicide application. Because the launch of acetolactate synthase (ALS)- and 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide-tolerant crops will increase the treated area, there is a need to assess the possible negative consequences of any particle drift from those herbicides. Drift happens with every pesticide application, requiring mitigation. Various factors influence drift. Some, such as nozzle type, working pressure, and boom height, can be managed. Others, such as wind, are not easy to manage. In our study, an herbicide tank mixture of mesotrione with rimsulfuron plus thifensulfuron-methyl was sprayed in a low-speed wind tunnel to simulate drift. The airspeed was set at 4.4 m s^-1, representing the labeled upper limit for applications. The herbicide solution was sprayed through XR110015 and TTI110015 nozzles. Eight crops were exposed to herbicide drift treatments and biomass data were collected. Droplet size spectra and tracer depositions were evaluated. Tracer deposition was on average threefold higher in all downwind distances (0.5, 1, 2, 3, 4, 6, 9, and 12 m) from the XR nozzle in comparison to the TTI nozzle. As a consequence, greater biomass reduction was recorded for applications with the XR compared to the TTI nozzle from 1 to 12 m downwind. At 12-m distance, biomass was decreased by 7-78% using XR nozzle while 1-27% using the TTI nozzle. Because drift can injure crops, it is very important to mitigate drift from application of formulations containing mesotrione and rimsulfuron plus thifensulfuron-methyl in combination. This can be done by selecting the appropriate nozzle and ensuring optimal distances between crops.

Strategies and techniques to mitigate the negative impacts of pesticide exposure to honey bees

In order to support food, fiber, and fuel production around the world, billions of kilograms of pesticides are applied to crop fields every year to suppress pests, plant diseases and weeds. These fields are often home to the most important commercial pollinators, honey bees (Apis spp.), which improve yield and quality of many agricultural products. The pesticides applied to support crop health can be detrimental to honey bee health. The conflict of pesticide use and reliance on honey bees contributes to significant honey bee colony losses across the world. Recommendations for reducing impact on honey bees are generally suggested in literature, pesticide regulations, and by crop consultants, but without a considerable discussion of the realistic limitations of protecting honey bees. New techniques in farming and beekeeping can reduce pesticide exposure through reduction in bee exposure, reduced toxicity of pesticides, and remedies that can be in response to exposure. However, lack of assessment of those new techniques under a systematical, comprehensive framework may overestimate or underestimate these techniques' potential to protect honey bees from pesticide damage. In this review, we summarize the current and arising strategies and techniques with the goal to inspire the development and adoption of pesticide mitigation practices for both agriculture and apiculture.

Exposure and risk assessment of acetamiprid in honey bee colonies under a real exposure scenario in Eucalyptus sp. landscapes

Honey bee colonies have shown abnormal mortality rates over the last decades. Colonies are exposed to biotic and abiotic stressors including landscape changes caused by human pressure. Modern agriculture and even forestry, rely on pesticide inputs and these chemicals have been indicated as one of the major causes for colony losses. Neonicotinoids are a common class of pesticides used worldwide that are specific to kill insect pests, with acetamiprid being the only neonicotinoid allowed to be applied outdoors in the EU. To evaluate honeybees' exposure to acetamiprid under field conditions as well as to test the use of in-situ tools to monitor pesticide residues, two honeybee colonies were installed in five Eucalyptus sp. plantations having different area where Epik® (active substance: acetamiprid) was applied as in a common spraying event to control the eucalyptus weevil pest. Flowers, fresh nectar, honey bees and colony products samples were collected and analyzed for the presence of acetamiprid residues. Our main findings were that (1) acetamiprid residues were found in samples collected outside the spraying area, (2) the amount of residues transported into the colonies increased with the size of the sprayed area, (3) according to the calculated Exposure to Toxicity Ratio (ETR) values, spraying up to 22 % of honeybees foraging area does not harm the colonies, (4) colony products can be used as a valid tool to monitor colony accumulation of acetamiprid and (5) the use of Lateral Flow Devices (LFDs) can be a cheap, fast and easy tool to apply in the field, to evaluate the presence of acetamiprid residues in the landscape and colony products.

Historical Agricultural Landforms—Central European Bio-Cultural Heritage Worthy of Attention

Knowledge about past agricultural land management can bring solutions for future needs. One undervalued historical type of historical rural landscape in temperate Europe is termed plužiny. It consists of individual historical agricultural landforms framed by linear woody vegetation. Our multidisciplinary research quantified the distribution of plužiny in Czechia, utilizing archive materials, geographic information systems, and field surveys for verification. Several case studies give merit to the societal relevance of plužiny and justification for their protection and inclusion in landscape planning. We have assessed the contribution of plužiny to secondary geodiversity by describing the landforms morphometrically, using geophysical imaging of their inner structure, and assessing the possible downslope erosive segregation of soil particles. The results of these analyses prove the positive effect of these landscape features on secondary geodiversity and biodiversity at the species level through the process of induced landscape diversification. The results also document management changes during the last 170 years and provide a basis for assessing their present-day endangerment. Although plužiny are less known compared to bocage landscapes of Western Europe, they are similarly valuable. Landscape managers should better recognize the ecological, cultural, and aesthetic values of plužiny as historical agricultural landforms and protect them as a bio-cultural heritage.

Ecological and historical factors behind the spatial structure of the historical field patterns in the Czech Republic

Historical field systems are an essential part of the traditional cultural landscape of societies with primarily agricultural subsistence. They embody many functions and values, as they affect the productional, ecological and hydrological functioning of the landscape, its cultural values, the way people perceive the landscape, and their impact on present-day farming. As an aspect of the historical landscape, field systems are a topic investigated in landscape archaeology, environmental studies, historical geography, landscape ecology, and related disciplines. Historical field systems can form many complex spatial structures, shapes and patterns. This paper focuses on identifying environmental and historical/cultural driving forces during the formation and the historical development of various field pattern types. We worked with 523 settlements established in the medieval to the early modern period (approx. 900–1600 AD) in the present-day Czech Republic. We have determined the proportions of different field pattern types in the examined cadastres and have statistically compared them with a variety of environmental and geographical predictors. Our results indicate a strong influence of environmental predictors (terrain undulation, cadastre size), the impact of specific historical events and associated social changes (e.g. land confiscations by the state in the seventeenth century), and a significant relationship between field pattern types and settlement layout types. Furthermore, we have observed the different adaptations of field pattern types to similar environmental conditions, as well as the impact of social and political factors on the processes of landscape formation. Our paper provides the first detailed analysis of the geographical distribution of traditional field systems on the scale of an entire modern state, and emphasizes the importance of transdisciplinary research on cultural landscapes.

Tree Advisor: A Novel Woody Plant Selection Tool to Support Multifunctional Objectives

Purposefully planted trees and shrubs can provide multiple benefits when appropriately planned and designed. Tools to help select species that will function more effectively than other species for ecosystem services, production, and aesthetic purposes are generally lacking. To address this challenge, we developed an interactive plant selection tool entitled Tree Advisor that rates woody species for a wide range of different purposes based on plant attributes. In this prototype decision support tool, 90 species of trees and shrubs are rated for 14 different purposes in the northern and central Great Plains region of the United States. A rating algorithm was developed based on the scientific literature regarding plant functions and related attributes that determine relative performance of a species for each purpose. User input and best practices for developing effective decision support tools informed the tool development process. Based on user feedback, the tool supports multifunctional planning and enables a user to quickly develop a short list of the better species to use which can then be refined by the user based on suitability under local site conditions, commercial availability, and availability of locally adapted cultivars and hybrids. This tool development approach can serve as a model for producing multifunctional woody plant selection tools for other ecoregions.

Are spray drift losses to agricultural roads more important for surface water contamination than direct drift to surface waters?

Spray drift is considered a major pesticide transport pathway to surface waters. Current research and legislation usually only considers direct spray drift. However, also spray drift on roads and subsequent wash-off to surface waters was identified as a possible transport pathway. Hydraulic shortcuts (storm drainage inlets, channel drains, ditches) have been shown to connect roads to surface waters, thus increasing the risk of drift wash-off to surface waters. However, the importance of this pathway has never been assessed on larger scales. To address this knowledge gap, we studied 26 agricultural catchments with a predominance of arable cropping (n = 17) and vineyards (n = 9). In these study sites, we assessed the occurrence of shortcuts by field mapping. Afterwards, we modelled the areas of roads drained to surface waters using a high-resolution digital elevation model (0.5 m resolution) and a multiple flow algorithm. Finally, we modelled drift deposition to drained roads and surface waters using a spatially explicit, georeferenced spray drift model. Our results show that for most sites, the drift to drained roads is much larger than the direct drift to surface waters. In arable land sites, drift to roads exceeds the direct drift by a factor of 4.5 to 18, and in vineyard sites by 35 to 140. In arable land sites, drift to drained roads is rather small (0.0015% to 0.0049% of applied amount) compared to typical total pesticide losses to surface waters. However, substantial drift to drained roads in vineyard sites was found (0.063% to 0.20% of applied amount). Current literature suggests that major fractions of the drift deposited on roads can be washed off during rain events, especially for pesticides with low soil adsorption coefficients. For such pesticides and particularly in vineyards, spray drift wash-off from drained roads is therefore expected to be a major transport pathway to surface waters.

Role of land use and land cover in residential exposures to agricultural pesticide models

Exposure of the general population to pesticides, especially in agricultural areas, is a major public health concern. This review analyses the role of Land Use and Land Cover (LULC) in Residential Exposure to Agricultural Pesticides (REAP) and how it is measured and modelled. Some epidemiological studies have shown that basic LULC variables, such as distance to a crop and field size, are relevant for explaining REAP. However, the potential of LULC mitigation elements, such as vegetation barriers, grassy strips and buffer zones, to mitigate REAP has been poorly studied. The availability of recent low-cost and high-quality geospatial data enables REAP models to include alternative and more precise LULC variables. This review also highlights the need for (i) generic environmental sampling protocols, (ii) exposure and spraying datasets and (iii) assessment of the mitigation capacity of LULC to improve REAP modelling significantly.

The use of hedgerows to mitigate pesticide exposure of a population living in a rural area

Farmer populations living in houses inside vegetable gardens are exposed to indoor pesticide pollution. The pulverization drift and volatile pesticides transported by wind are important sources of indoor pollution, which can be mitigated by hedgerows. This study was the first attempt in Brazil to investigate the efficiency of six different hedgerow species in reducing pesticide residues in air. A fluorescent compound (p-aminobenzoic acid or PABA) was introduced in the sprayed pesticide fluid that traced the pesticide in the water. Samples were collected in Petri dishes positioned on stakes at different heights in front of and behind the hedgerows. Data indicated barrier efficiency of up to 99%. Simulation of nontarget drift contamination with herbicide concentrations exhibited reduced senescence effects on leaves and posed no threat to survival. Hedgerows are feasible, simple, and inexpensive techniques, which may be used easily by farmers, independent of external support and efficiently mitigating indoor pesticide pollution, thus protecting human health. Integr Environ Assess Manag 2022;18:19-24. © 2021 SETAC.

A multi-criteria approach to evaluate the sustainability performances of wines: the Italian red wine case study

The wine industry has faced two significant environmental problems in recent years: productivity is challenged by environmental trends such as global warming, and buyers are becoming more environmentally conscious. From an environmental standpoint, the food industry is one of the most impacting sectors and wine results as one of the most studied agri-food products in the scientific literature. In general, comprehensive studies that consider an application of set of indicators to evaluate the overall sustainability of wine sector are lacking in literature. This paper aims to carry out a sustainable assessment using different indicators for fifteen Italian red wines: Water Footprint (WF), Carbon Footprint (CF), Vineyard Indicator (VI), and Territory Indicator (TI). VI is an indicator of the vineyard's agronomic management's sustainability at plot level with values ranging from 0 (fully sustainable) to 1 (fully not sustainable), while TI covers the socio-economical aspects of sustainability. Considering system boundaries from cradle to grave, at 90% confidence interval, CF results ranged between 0.97 kg CO₂ eq./functional unit and 1.97 kg CO₂ eq./functional unit, with an average estimated at 1.47 kg CO₂ eq./functional unit, while the WF of a 0.75 L bottle of wine from cradle to gate is 666.7 L/functional unit on average, out of which 86.75% is green, 1.92% is blue and 11.34% is grey water. Concerning the VI, at 90% confidence interval VI results were between 0.117 and 0.498 with an average estimated at 0.307. The results of the correlation analyses confirmed that each indicator is not statistically correlated with each other. Concerning the sub-indicators, a positive correlation has been found between the total CF and the sum of blue and grey WF. The application of a multi-criteria analysis for sustainability performances evaluation of the wine sector presented in this study can be used by wine companies' experts to better assess sustainability performances.

Deposition of dust with active substances in pesticides from treated seeds in adjacent fields during drilling: disentangling the effects of various factors using an 8-year field experiment

The side effects from the use of plant protection products and their potential effects on non-target arthropods (NTAs) such as honey bees, other insects within the vegetation layer and epigeic arthropods nowadays receive more attention. However, uncertainties about the factors driving the deposition of active substances (a.s.) into off-crop areas persist, in particular during sowing of treated seeds. Analysing a highly standardised 8-year field experiment, we assessed the importance of various factors potentially affecting dust drift and deposition of a.s., emitted during the sowing process of treated seeds and deposited on fields adjacent to the drilling field, i.e. on the ground, on flowers, and on nonflowering plant parts. Regarding a.s. deposition, the Heubach a.s. value has a predictive capability, which is independent from all other factors taken into account in this study, and can thus be considered as a scenario-independent measure of potential dust deposition. Petri dish samplers, an established standard method for measuring a.s. deposition, were representative of the results from the plant samplers for a given combination of drilling technique and adjacent crop type. Adjacent crop type is likely to impact on a.s. deposition. The present work will enable a more field-realistic exposure assessment for bees and other NTAs.

The effect of vegetation barriers at reducing the transmission of Salmonella and Escherichia coli from animal operations to fresh produce

Due to the recent outbreaks of Salmonella and Escherichia coli in fresh produce in the United States, the transfer of foodborne pathogens between animal feeding operations and fresh produce continues to be a considerable risk. The purpose of this study was to determine if the establishment of a vegetation barrier (VB) on small-scale sustainable farms could prevent the transmission of Salmonella and E. coli to nearby fresh produce fields. A 5-layer VB (31 × 49 m) was constructed between a dairy farm, a poultry farm, and a nearby produce field. Fresh produce (i.e., romaine lettuce and tomato), animal feces, and environmental (i.e., air, soil, and barrier) samples were collected for 15 months from 2018 to 2019. Four replicates of soil and fresh produce samples were taken from three plots located 10 m, 61 m, and 122 m away from the respective animal locations and processed for Salmonella and E. coli. Air and vegetative strip samples were sampled at 15-day intervals. Multiple colonies were processed from each positive sample, and a total of 143 positive Salmonella (n = 15) and E. coli (n = 128) isolates were retrieved from the soil, produce, air, and fecal samples. Interestingly, 18.2% of the Salmonella and E. coli isolates (n = 26) were recovered from fresh produce (n = 9) samples. Surprisingly, Salmonella isolates (n = 9) were only found in fecal (n = 3) samples collected from the dairy pasture. Data analysis suggests that the VB is an effective tool at reducing the transmission of E. coli and Salmonella from animal farms to fresh produce fields. However, based on phenotypic and genotypic testing, it is clear that fecal samples from animal farms are not the only source of pathogen contamination. This indicates that the environment (e.g., soil and wind), as well as the initial setup of the farm (e.g., proximity to service roads and produce plot placement), can contribute to the contamination of fresh produce. Our study recommends the need for more effective bioremediation and prevention control measures to use in conjunction with VBs to reduce pathogen transmission.

Evaluating the Impact of Post-Emergence Weed Control in Honeybee Colonies Located in Different Agricultural Surroundings

The honeybee Apis mellifera is exposed to agricultural intensification, which leads to an improved reliance upon pesticide use and the reduction of floral diversity. In the present study, we assess the changes in the colony activity and the expression profile of genes involved in xenobiotic detoxification in larvae and adult honeybees from three apiaries located in agricultural environments that differ in their proportion of the crop/wild flora. We evaluated these variables before and after the administration of a mixture of three herbicides during the summer season. The expression of several cytochrome P450 monooxygenases decreased significantly in larvae after post-emergence weed control and showed significant differences between apiaries in the case of honeybee workers. Principal component analysis (PCA) revealed that colonies located in the plot near to a wetland area exhibited a different relative gene expression profile after herbicide application compared with the other plots. Moreover, we found significant positive correlations between pollen collection and the pesticide detoxification genes that discriminated between plots in the PCA. Our results suggest that nutrition may modify herbicide impact on honeybees and that larvae are more harmed than adults in agroecosystems, a factor that will alter the colonies' population growth at the end of the blooming period.

Spray drift mitigation using opposing synchronized air-blast sprayers

BACKGROUND

Pesticide drift is a serious environmental and safety concern that affects all of US agriculture. A number of mitigation techniques to reduce pesticide drift have been recommended by industry, academic and government agencies. These techniques are very costly or reduce the efficacy of the pest control product and have not been implemented by US agriculture.

RESULTS

When using a novel spray technique (Air-in), pesticide drift was significantly reduced by between 53% and 99% at 7.6 m from the orchard drip line when compared to the grower standard. This technique not only reduced pesticide drift, but also maintained or improved the amount of pesticide residue deposited (by 0.7-2.6-fold) and the percentage pesticide coverage (by 1.0-1.4-fold) with different air-blast speed sprayers on almond, walnut and pistachio.

CONCLUSION

The Air-in technique shows great promise in reducing pesticide drift while maintaining or improving pesticide coverage with minimal cost to the grower.

Optimizing Caneberry Spray Coverage for Drosophila suzukii (Diptera: Drosophilidae) Management on Diversified Fruit Farms

Spray coverage may influence the efficacy of insecticides targeting the invasive vinegar fly Drosophila suzukii (Matsumura), a primary pest of raspberries and blackberries. In commercially managed caneberries, spray coverage is typically lowest in the inner and lower plant canopy, regions that overlap with higher levels of adult D. suzukii activity. To understand how spray coverage of fruit impacts efficacy against D. suzukii, laboratory bioassays were conducted using raspberries. In laboratory bioassays, higher spray coverage did not impact larval infestation rates but did increase adult mortality, indicating that flies can avoid a lethal dose of insecticide when applications do not achieve adequate coverage. We also evaluated how carrier water volume impacts spray coverage patterns throughout the canopy of raspberry and blackberry plants using both airblast and CO2 backpack sprayers. Increasing carrier water volume generally improved spray coverage in the lower plant canopy. However, effects in the upper plant canopy were inconsistent and varied between sprayer types. In addition to carrier water volume, other approaches, including adjusting the pesticide sprayer equipment used and/or sprayer calibration, should also be explored to improve coverage. Growers should evaluate spray coverage in their caneberries to identify and troubleshoot coverage issues. Results from this study indicate that taking the time to optimize this aspect of pesticide application may improve chemical management of D. suzukii and will likely also improve control of other important caneberry pests.

Crop proximity index for monitoring of peri-urban land use in agro-industrial crop regions

The agro-industrial production of genetically modified organisms uses great amounts of pesticides, close to cities, which generates growing concern due to the numerous evidence of their negative effects on health and the environment. In a context of the lack, or inaccessibility, of official data on crop dynamics and pesticide use, environmental indicators using satellite data are needed for the proper monitoring of peri-urban areas. The objective of this research is to make a crop proximity index using satellite information to assess and monitor peri-urban agro-industrial activity. Twenty cities in Argentina and ten in the United States were selected. The CPI index is designed to evaluate a city and its peri-urban areas as a whole by taking account of the land uses and factors that can potentially influence the proximity to agro-industrial activity to the population living in those cities. Agriculture factor was weighted by proximity or remoteness using perimeter rings from the urban edge. All the necessary data for the calculation of the CPI index were obtained through the classification and processing of Sentinel 2 satellite images with software and the Google Earth Engine platform. The results show a worrying situation, 90% of cities in Argentina and 80% in the United States have a negative CPI. Most of the cities examined are extremely close to extensive areas of crops, that use a high amount of pesticides and which do not have the protection of trees or buffer zones.

Temperate Agroforestry Systems and Insect Pollinators: A Review

Agroforestry can provide ecosystem services and benefits such as soil erosion control, microclimate modification for yield enhancement, economic diversification, livestock production and well-being, and water quality protection. Through increased structural and functional diversity in agricultural landscapes, agroforestry practices can also affect ecosystem services provided by insect pollinators. A literature review was conducted to synthesize information on how temperate agroforestry systems influence insect pollinators and their pollination services with particular focus on the role of trees and shrubs. Our review indicates that agroforestry practices can provide three overarching benefits for pollinators: (1) providing habitat including foraging resources and nesting or egg-laying sites, (2) enhancing site and landscape connectivity, and (3) mitigating pesticide exposure. In some cases, agroforestry practices may contribute to unintended consequences such as becoming a sink for pollinators, where they may have increased exposure to pesticide residue that can accumulate in agroforestry practices. Although there is some scientific evidence suggesting that agroforestry practices can enhance crop pollination and yield, more research needs to be conducted on a variety of crops to verify this ecosystem service. Through a more comprehensive understanding of the effects of agroforestry practices on pollinators and their key services, we can better design agroforestry systems to provide these benefits in addition to other desired ecosystem services.

The Effectiveness of Riparian Hedgerows at Intercepting Drift from Aerial Pesticide Application

The primary tool used currently for preventing pesticide drift from entering streams is a no-spray buffer zone. Riparian hedgerows may provide an additional option; however, quantitative information on their effectiveness is limited. To quantify the potential benefit of riparian hedgerows for drift reduction, aerial malathion {diethyl 2-[(dimethoxyphosphorothioyl)sulfanyl]butanedioate} applications on blueberry ( L.) farms with fields adjacent to streams or ditches were monitored. Drift from fields with extensive dense woody riparian vegetation was compared with drift from fields with no dense woody riparian vegetation. Overall, total instream malathion deposition was 96.1% lower at vegetated sites compared with nonvegetated sites. Univariable models identified six variables that were significantly related to decreasing instream total malathion deposition: increasing bank canopy cover, increasing average site canopy cover, increasing canopy angle, increasing the distance between the field edge and vegetation edge, increasing the distance between the field edge and center of stream, and decreasing bank slope. For the variables most feasible for landowners to alter, the following increases could result, on average, in a 26% decrease in the total instream malathion deposition: bank canopy cover (7%), distance between field and vegetation (0.3 m), and distance between field and center of stream (0.9 m). No-spray buffer sizes needed for significant deposition reductions may be large, but for nonvegetated or minimally vegetated streams similar to those studied here, increasing bank canopy cover may give comparable advantages while allowing the use of the entire field area and conferring additional ecosystem benefits such as shading streams and improving habitat.

Effects of a glyphosate-based herbicide on survival and oxidative status of a non-target herbivore, the Colorado potato beetle (Leptinotarsa decemlineata)

Glyphosate is the globally most used herbicide against a wide range of weeds. Glyphosate has been considered safe to animals as it mainly targets physiological pathways in plants. However, recent toxicological studies have revealed that glyphosate can cause various toxic effects also on animals. In this study, we investigated the direct toxic effects of a glyphosate-based herbicide (GBH, Roundup® Bio) on 1) survival and 2) oxidative status of a non-target herbivore by using Colorado potato beetles (Leptinotarsa decemlineata), originating from Poland and USA, as model species. Larvae were randomly divided into three groups: 1) high concentration (100% Roundup Bio, 360 g/l), 2) low concentration (1.5% Roundup Bio) and 3) control group (water). Larvae were exposed to Roundup for different time periods: 2 h, 24 h, 48 h, 72 h and 96 h. Larval survival decreased in the group treated with high concentration of GBH compared to controls, whereas the low concentration group did not differ from the control group. GBH treatment had no association with oxidative status biomarkers (i.e. catalase, superoxide dismutase, glutathione-S-transferase, glutathione and glutathione related enzymes), but increased lipid hydroperoxide levels after 2 h exposure, suggesting increased oxidative damage soon after the exposure. Larvae of different origin also differed in their oxidative status, indicating population-dependent differences in antioxidant defence system. Environmentally relevant concentrations of GBH are not likely to affect larval survival, but high concentrations can reduce survival and increase oxidative damage of non-target herbivores. Also, populations of different origin and pesticide usage history can differ in their tolerance to GBH.

The evil within? Systemic fungicide application in trees enhances litter quality for an aquatic decomposer-detritivore system

Waterborne exposure towards fungicides is known to trigger negative effects in aquatic leaf-associated microbial decomposers and leaf-shredding macroinvertebrates. We expected similar effects when these organisms use leaf material from terrestrial plants that were treated with systemic fungicides as a food source since the fungicides may remain within the leaves when entering aquatic systems. To test this hypothesis, we treated black alder (Alnus glutinosa) trees with a tap water control or a systemic fungicide mixture (azoxystrobin, cyprodinil, quinoxyfen, and tebuconazole) at two worst-case application rates. Leaves of these trees were used in an experiment targeting alterations in two functions provided by leaf-associated microorganisms, namely the decomposition and conditioning of leaf material. The latter was addressed via the food-choice response of the amphipod shredder Gammarus fossarum. During a second experiment, the potential impact of long-term consumption of leaves from trees treated with systemic fungicides on G. fossarum was assessed. Systemic fungicide treatment altered the resource quality of the leaf material resulting in trends of increased fungal spore production and an altered community composition of leaf-associated fungi. These changes in turn caused a significant preference of Gammarus for microbially conditioned leaves that had received the highest fungicide treatment over control leaves. This higher food quality ultimately resulted in a higher gammarid growth (up to 300% increase) during the long-term feeding assay. Although the underlying mechanisms still need to be addressed, the present study demonstrates a positive indirect response in aquatic organisms due to systemic pesticide application in a terrestrial system. As the effects from the introduction of plant material treated with systemic fungicides strongly differ from those mediated via other pathways (e.g., waterborne exposure), our study provides a novel perspective of fungicide-triggered effects in aquatic detritus-based food webs.

Strategies for reducing airborne pesticides under tropical conditions

Brazil is currently one of the largest pesticide consumers worldwide. However, a lack of scientific information regarding airborne pollution is still an issue, with tragic consequences to human health and the environment. To reduce pollution of the lower air layers, where pesticide spraying occurs, green barriers that filter the air could be an effective mitigation procedure. Modifying pulverization habits, by pulverizing in the late afternoon instead of in the morning could also reduce pesticide volatilization, while other recommendations with the purpose of lowering the pesticide amounts currently applied are likewise pursued. Data obtained about volatilization have demonstrated that, in order to reduce air pollution risks, one of the most effective preventive strategies is to ban products with high vapor pressure. Global/local stakeholders need to assume the responsibility to find the best way to reduce airborne pesticide pollution, which has increasingly shown disastrous effects as major poisons to human health and the environment.

Tree Belts for Decreasing Aeolian Dust-Carried Pesticides from Cultivated Areas

The aim of this study was to investigate the function of tree belts in reducing the aeolian transport of dust particles carrying pesticides. The study examined the importance of the buffer zones created by commonly planted trees (Eucalyptus camaldulensis, Pinus halepensis (pine) and Ceratonia siliqua (carob)). The methods include analyzing the quantity and the chemical composition of pesticides carried by aeolian dust particles from the intensively cultivated fields and orchards, where pesticides were applied, towards the tree belts nearby. Eighteen different chemicals used as insecticides, fungicides and herbicides, were found both in the agricultural fields and in the adjacent tree belts, suggesting an important function of the trees. This ecological service has rarely been taken into consideration by management policies of tree plantings in farmland areas. To integrate this service into agriculture, especially in the case of agricultural fields and orchards, which are adjacent to populated areas, planting tree belts should be positively considered as a means for reducing aeolian dust and air pollution, mainly in order to reduce leakage of pesticides, which are a cause for significant health concerns.

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.

Ecological intensification to mitigate impacts of conventional intensive land use on pollinators and pollination

Worldwide, human appropriation of ecosystems is disrupting plant–pollinator communities and pollination function through habitat conversion and landscape homogenisation. Conversion to agriculture is destroying and degrading semi‐natural ecosystems while conventional land‐use intensification (e.g. industrial management of large‐scale monocultures with high chemical inputs) homogenises landscape structure and quality. Together, these anthropogenic processes reduce the connectivity of populations and erode floral and nesting resources to undermine pollinator abundance and diversity, and ultimately pollination services. Ecological intensification of agriculture represents a strategic alternative to ameliorate these drivers of pollinator decline while supporting sustainable food production, by promoting biodiversity beneficial to agricultural production through management practices such as intercropping, crop rotations, farm‐level diversification and reduced agrochemical use. We critically evaluate its potential to address and reverse the land use and management trends currently degrading pollinator communities and potentially causing widespread pollination deficits. We find that many of the practices that constitute ecological intensification can contribute to mitigating the drivers of pollinator decline. Our findings support ecological intensification as a solution to pollinator declines, and we discuss ways to promote it in agricultural policy and practice.

Characterization of the fate and distribution of ethiprole in water-fish-sediment microcosm using a fugacity model

A novel, relatively simple and effective three-compartment level IV fugacity model was developed to quantitatively describe the fate, transformation and transport of ethiprole in an aquatic system. Chemical equilibrium was assumed to apply within each bulk compartment. Expressions are included for degradation reactions, advective flow, emission, and interphase transport by non-diffusive and diffusive processes. The simulated results closely matched the results obtained from the experiments. The model indicated that at 25°C (day:night=12h:12h), after approximately 672h, Results of the model calculations showed that the ethiprole was degraded by both photolysis and microorganisms in the water accounts for 86.8% (account for 90.4%, 95.4% in Beijing (BJ) and Hunan (HN) microcosm respectively) of the total removal, the ethiprole was removed by advective outflow accounts for 0.15% (accounts for 0.05%, 0.1% in HN and BJ microcosm respectively) of the total removal, the ethiprole were removed by biodegradation in sediment and fish, accounts for 8.54% and 5.55% (accounts for 2.52% and 2.03%, 5.6% and 3.7% in HN and BJ microcosm respectively) of the total removal respectively in HLJ microcosm. It indicates that biodegradation and photolysis in the water phase were the most important removal process, and most of the ethiprole was distributed in the water phase. A sensitivity analysis of the input parameters indicates that the Henry's law constant (H) and octanol-water partition coefficient (K_ow) parameters are the both most sensitive to the ethiprole concentration in the medium, which suggests that the H and K_ow have important impact on both the distribution and variance of the contaminant concentration. The mass balance under steady-state conditions showed that over 90% of ethiprole stay in water for all microcosm. This finding demonstrates that water plays a key role in the fate of ethiprole, acting as the major sink for contaminants in the stimulation system.

Field scale boscalid residues and dissipation half-life estimation in a sandy soil

The aim of this study was to analyze the environmental fate of the fungicide boscalid in a sandy soil. Boscalid was applied in spring 2010/11 to a cropland site in western Germany. Three years after second application 65 undisturbed soil samples were taken. Boscalid was extracted using accelerated solvent extraction (ASE). Boscalid contents in the plough horizon ranged between 0.12 and 0.53 with a field mean of 0.20 ± 0.09 μg kg(-1). These contents were considerably lower compared to calculation using literature DT50 values, whereby a concentration of 16.89 μg kg(-1) was expected assuming a literature DT50 value of 345 days. Therefore, the measured field boscalid concentration only yields 1.2% of the expected value. To test whether the unknown extraction efficiency, losses from spray drift and interception can explain the mismatch between calculated and measured concentrations all these uncertainties were taken into account into calculations, but field concentrations and DT50 were still lower as expected. Leaching to deeper horizons was also studied but could not explain the discrepancy either. Moreover, a short-term incubation experiment using (14)C labelled boscalid revealed also shorter DT50 values of 297-337 compared to the 345 days taken from literature. However, this DT50 value is still considerably larger compared to the 104-224 days that were calculated based on the field experiment. Our results indicate that boscalid dissipation under field conditions is much faster at agricultural sites with sandy soil type as expected from laboratory incubation experiments.

Risk mitigation measures for diffuse pesticide entry into aquatic ecosystems: proposal of a guide to identify appropriate measures on a catchment scale

Measures to mitigate the risk of pesticide entry into aquatic ecosystems are becoming increasingly more important in the management of hot spots of pesticide transfer; such management, for example, is required by the European Union's directive for the sustainable use of pesticides (2009/128/EC). Measures beyond those currently stipulated for pesticide product authorization may be needed. A concise compilation of the appropriate measures for users (that are primarily farmers but also, e.g., regulators and farm extension services) and a guide for practically identifying these measures at the catchment scale is currently not available. Therefore, a proposal was developed for a guide focusing on the most important diffuse entry pathways (spray drift and runoff). Based on a survey of exposure-relevant landscape parameters (i.e., the riparian buffer strip width, riparian vegetation type, density of ground vegetation cover, coverage of the water body with aquatic macrophytes, field slope, and existence of concentrated flow paths), a set of risk mitigation measures focusing on the specific situation of pollution of a water body catchment can be identified. The user can then choose risk mitigation measures to implement, assisted by evaluations of their efficiency in reducing pesticide entry, feasibility, and expected acceptability to farmers. Currently, 12 landscape-related measures and 6 application-related measures are included. The present guide presents a step toward the practical implementation of risk mitigation measures for reducing pesticide entry in aquatic ecosystems.

Environmental determinants of the urinary concentrations of herbicides during pregnancy: the PELAGIE mother-child cohort (France)

Herbicides are generally the most extensively used of the pesticides applied to agricultural crops. However, the literature contains little evidence useful in assessing the potential sources of the general population's exposure to herbicides, including by residential proximity to crops. The objective of this study was to take advantage of data from the PELAGIE mother-child cohort to identify the main determinants of the body burden of exposure to the chloroacetanilide and triazine herbicides commonly used on corn crops in Brittany, France, before 2006. Urine samples from a randomly selected subcohort of women in the first trimester of pregnancy (n=579) were assayed for herbicide metabolites. The residential exposure resulting from proximity to corn crops was assessed with satellite-image-based scores combined with meteorological data. Data on diet, drinking tap water (from the public water supply), occupations, and household herbicide use were collected by questionnaires. Herbicides were quantified in 5.3% to 39.7% of urine samples. Alachlor and acetochlor were found most frequently in the urine of women living in rural areas. The presence of dealkylated triazine metabolites in urine samples was positively associated with residential proximity to corn crops (OR=1.38, 95% CI: 1.05-1.80). Urinary metabolites of both atrazine and dealkylated triazine were correlated with tap water consumption (OR=2.94, 1.09-7.90, and OR=1.82, 1.10-3.03, respectively); hydroxylated triazine metabolites were correlated with fish intake (OR=1.48, 1.09-1.99). This study reinforces previous results that suggest that environmental contamination resulting from agricultural activities may contribute to the general population's exposure to herbicides.

Environmental attitudes and drift reduction behavior among commercial pesticide applicators in a U.S. agricultural landscape

Pesticide drift is a significant environmental problem in rural regions, and can result in losses to certain non-target crops and livestock, water and air pollution, and threats to human health. While state agencies seek to control the harmful effects of pesticides through licensing and certificate programs, the adoption rates of drift-reducing practices by commercial applicators remain highly variable. In order to effectively target outreach efforts to commercial applicators, managers need to better understand current use patterns and the motivations behind the adoption and non-adoption of preferred practices. Using a web and mail survey, this study explored environmental attitudes, awareness and concern for pesticide drift, and current practice adoption for drift reduction by commercial pesticide applicators in Indiana. Researchers surveyed three distinct applicator types: industrial weed management (utility right-of-way), agriculture, and aerial (which are mostly spraying in an agricultural setting). Overall, applicators exhibited positive environmental attitudes, but low concern for pesticide drift in the geographic areas where they operate. Adoption rates for several drift reduction technologies were high, particularly for equipment and spray modifications such as low-drift spray nozzles (88%) and increased spray droplet size (92%). Applicators were less familiar with specialty equipment (such as band sprayers, 13% adoption rate) and methods for identifying sensitive sites such as bee colonies and organic crops. Among the three groups, industrial weed management applicators had the lowest adoption rates. Applicators were motivated to adopt drift-reduction practices by the desire to be a good neighbor and a desire to be a good land steward. There is potential for use of more innovative, voluntary approaches to raise awareness of sites sensitive to pesticide drift in rural landscapes.

Agrochemical spray drift; assessment and mitigation--a review

During application of agrochemicals spray droplets can drift beyond the intended target to non-target receptors, including water, plants and animals. Factors affecting this spray drift include mode of application, droplet size, which can be modified by the nozzle types, formulation adjuvants, wind direction, wind speed, air stability, relative humidity, temperature and height of released spray relative to the crop canopy. The rate of fall of spray droplets depends upon the size of the droplets but is modified by entrainment in a mobile air mass and is also influenced by the rate of evaporation of the liquid constituting the aerosol. The longer the aerosol remains in the air before falling to the ground (or alternatively striking an object above ground) the greater the opportunity for it to be carried away from its intended target. In general, all size classes of droplets are capable of movement off target, but the smallest are likely to move the farthest before depositing on the ground or a non-target receptor. It is not possible to avoid spray drift completely but it can be minimized by using best-management practices. These include using appropriate nozzle types, shields, spray pressure, volumes per area sprayed, tractor speed and only spraying when climatic conditions are suitable. Field layout can also influence spray drift, whilst crop-free and spray-free buffer zones and windbreak crops can also have a mitigating effect. Various models are available to estimate the environmental exposure from spray drift at the time of application.

Water body and riparian buffer strip characteristics in a vineyard area to support aquatic pesticide exposure assessment

The implementation of a geodata-based probabilistic pesticide exposure assessment for surface waters in Germany offers the opportunity to base the exposure estimation on more differentiated assumptions including detailed landscape characteristics. Since these characteristics can only be estimated using field surveys, water body width and depth, hydrology, riparian buffer strip width, ground vegetation cover, existence of concentrated flow paths, and riparian vegetation were characterised at 104 water body segments in the vineyard region Palatinate (south-west Germany). Water body segments classified as permanent (n=43) had median values of water body width and depth of 0.9m and 0.06m, respectively, and the determined median width:depth ratio was 15. Thus, the deterministic water body model (width=1m; depth=0.3m) assumed in regulatory exposure assessment seems unsuitable for small water bodies in the study area. Only 25% of investigated buffer strips had a dense vegetation cover (>70%) and allow a laminar sheet flow as required to include them as an effective pesticide runoff reduction landscape characteristic. At 77 buffer strips, bordering field paths and erosion rills leading into the water body were present, concentrating pesticide runoff and consequently decreasing buffer strip efficiency. The vegetation type shrubbery (height>1.5m) was present at 57 (29%) investigated riparian buffer strips. According to their median optical vegetation density of 75%, shrubberies may provide a spray drift reduction of 72±29%. Implementing detailed knowledge in an overall assessment revealed that exposure via drift might be 2.4 and via runoff up to 1.6 fold higher than assumed by the deterministic approach. Furthermore, considering vegetated buffer strips only by their width leads to an underestimation of exposure by a factor of as much as four. Our data highlight that the deterministic model assumptions neither represent worst-case nor median values and therefore cannot simply be adopted in a probabilistic approach.

Trace level determination of selected sulfonylurea herbicides in wetland sediment by liquid chromatography electrospray tandem mass spectrometry

Sulfonylurea herbicides are widely used in crop production on the Canadian prairies and a portion of these herbicides applied to cropland are inevitably lost to surrounding aquatic ecosystems. Little is known regarding the presence of sulfonylurea herbicides in wetlands located amongst cropland. This paper describes a new analytical method for the extraction and the determination of seven sulfonylurea herbicides (thifensulfuron-methyl, tribenuron-methyl, ethametsulfuron-methyl, metsulfuron-methyl, rimsulfuron, nicosulfuron and sulfosulfuron) in wetland sediment. The method provided > 85% analyte recovery from fortified sediment for six of the seven sulfonylurea herbicides with a limit of quantification (LOQ) of 1.0 microg kg(-1). Tribenuron-methyl had significantly lower recovery compared to the other six sulfonylurea herbicides (LOQ = 2 microg kg(-1)). Mean recovery standard deviations were < 10%. This methodology was used to quantify sulfonylurea herbicide residues in sediment samples collected from prairie wetlands situated within the agricultural landscape of Saskatchewan and Manitoba, Canada. This is the first-known detection of sulfonylurea herbicide residues in prairie wetland sediments. Ethametsulfuron-methyl, sulfosulfuron and metsulfuron-methyl, the three most environmentally persistent of the seven sulfonylurea herbicides monitored in the surveillance component of this study, were most frequently detected in wetland sediment with mean concentrations ranging from 1.2 to 10 microg kg(-1).

Impacts of red meat production on biodiversity in Australia: a review and comparison with alternative protein production industries

All food production systems are under pressure to comply with societal expectations that the produce is not only of good nutritional value but is also sustainably produced. This review compares the performance of the red meat industry in Australia against white meat, plant-protein and other protein production systems across a range of biodiversity pressures through a review of over 500 peer-reviewed and other scientific sources. The review finds that taking into account the past legacy of red meat production systems, these industries make the largest relative potential contribution to the impact on terrestrial biodiversity in Australia, by both the area covered and the nature of the impacts. The review also finds that many initiatives of the beef and sheep industries have the potential to improve the management of biodiversity. To minimise the impact of beef and sheep meat systems on biodiversity, the conservation of natural resources needs to become a core and integral part of production systems, rather than it being perceived as an optional extra if times are good. To help address these challenges, stewardship payments for the ecosystem services (such as carbon, water and biodiversity) provided by the farming community to the wider society warrant further consideration.

Mitigation strategies to reduce pesticide inputs into ground- and surface water and their effectiveness; a review

In this paper, the current knowledge on mitigation strategies to reduce pesticide inputs into surface water and groundwater, and their effectiveness when applied in practice is reviewed. Apart from their effectiveness in reducing pesticide inputs into ground- and surface water, the mitigation measures identified in the literature are evaluated with respect to their practicability. Those measures considered both effective and feasible are recommended for implementing at the farm and catchment scale. Finally, recommendations for modelling are provided using the identified reduction efficiencies. Roughly 180 publications directly dealing with or being somehow related to mitigation of pesticide inputs into water bodies were examined. The effectiveness of grassed buffer strips located at the lower edges of fields has been demonstrated. However, this effectiveness is very variable, and the variability cannot be explained by strip width alone. Riparian buffer strips are most probably much less effective than edge-of-field buffer strips in reducing pesticide runoff and erosion inputs into surface waters. Constructed wetlands are promising tools for mitigating pesticide inputs via runoff/erosion and drift into surface waters, but their effectiveness still has to be demonstrated for weakly and moderately sorbing compounds. Subsurface drains are an effective mitigation measure for pesticide runoff losses from slowly permeable soils with frequent waterlogging. For the pathways drainage and leaching, the only feasible mitigation measures are application rate reduction, product substitution and shift of the application date. There are many possible effective measures of spray drift reduction. While sufficient knowledge exists for suggesting default values for the efficiency of single drift mitigation measures, little information exists on the effect of the drift reduction efficiency of combinations of measures. More research on possible interactions between different drift mitigation measures and the resulting overall drift reduction efficiency is therefore indicated. Point-source inputs can be mitigated against by increasing awareness of the farmers with regard to pesticide handling and application, and encouraging them to implement loss-reducing measures of "best management practice". In catchments dominated by diffuse inputs at least in some years, mitigation of point-source inputs alone may not be sufficient to reduce pesticide loads/concentrations in water bodies to an acceptable level.

Mitigation of azinphos-methyl in a vegetated stream: comparison of runoff- and spray-drift

The effectiveness of aquatic macrophytes in reducing runoff- and spray-drift-induced azinphos-methyl (AZP) input was compared in a vegetated stream. Water, sediment and plant samples were taken at increasing distances from a point of input during a spray-drift event and two runoff (10 and 22 mm/day) events. Peak concentrations of AZP decreased significantly (R2=0.99; p<0.0001; n=5) from 0.24 microg/l to 0.11 microg/l during the 10mm runoff event. No reduction took place during the 22 mm event. AZP concentrations were reduced by 90% following spray-drift input, with peak concentrations decreasing significantly (R2=0.93; p=0.0084; n=5) from 4.3 microg/l to 1.7 microg/l with increasing distance from the point of input. Plant samples taken after the spray-drift event showed increased AZP concentrations in comparison to before the event indicating sorption of the pesticide to the macrophytes. Although peak concentrations of AZP were as effectively mitigated during the 10mm runoff event as during the spray-drift event, predictive modelling revealed that maximum concentrations expected during a worst-case scenario 10mm runoff event (0 days after application) are an order of magnitude lower than what can be expected for a worst-case spray-drift and 22 mm runoff event, suggesting that spray-drift-derived pesticide concentrations are more effectively mitigated than those of runoff.

Buffer zone and windbreak effects on spray drift deposition in a simulated wetland

The amount of agricultural spray that drifts into a wetland from an adjacent crop field is influenced by vegetation along the field boundary or any intentional setback distance (buffer zone) between the sprayer and the edge of the arable field. In this study, spray tracer drift deposits were measured in a simulated wetland area under different conditions of wind speed and buffer zone width. The effect of an artificial windbreak at the upwind edge of the simulated wetland was also evaluated. A level of tolerance of 0.1% of the in-swath spray deposition was established as a no-effect level for the response of aquatic plants to common herbicides. Our results indicate that a vegetated 10-m field margin (eg a fencerow) alone provides adequate protection from herbicide drift into a wetland area under wind conditions normally considered acceptable for spraying. For high winds (> 4m s(-1)) when field spraying would not normally be advised, adequate protection was afforded by the same 10-m margin plus a dense windbreak (25% porosity) or by the margin plus a 20-m buffer zone.

Field studies on exposure, effects, and risk mitigation of aquatic nonpoint-source insecticide pollution: a review

Recently, much attention has been focused on insecticides as a group of chemicals combining high toxicity to invertebrates and fishes with low application rates, which complicates detection in the field. Assessment of these chemicals is greatly facilitated by the description and understanding of exposure, resulting biological effects, and risk mitigation strategies in natural surface waters under field conditions due to normal farming practice. More than 60 reports of insecticide-compound detection in surface waters due to agricultural nonpoint-source pollution have been published in the open literature during the past 20 years, about one-third of them having been undertaken in the past 3.5 years. Recent reports tend to concentrate on specific routes of pesticide entry, such as runoff, but there are very few studies on spray drift-borne contamination. Reported aqueous-phase insecticide concentrations are negatively correlated with the catchment size and all concentrations of > 10 microg/L (19 out of 133) were found in smaller-scale catchments (< 100 km2). Field studies on effects of insecticide contamination often lack appropriate exposure characterization. About 15 of the 42 effect studies reviewed here revealed a clear relationship between quantified, non-experimental exposure and observed effects in situ, on abundance, drift, community structure, or dynamics. Azinphos-methyl, chlorpyrifos, and endosulfan were frequently detected at levels above those reported to reveal effects in the field; however, knowledge about effects of insecticides in the field is still sparse. Following a short overview of various risk mitigation or best management practices, constructed wetlands and vegetated ditches are described as a risk mitigation strategy that have only recently been established for agricultural insecticides. Although only 11 studies are available, the results in terms of pesticide retention and toxicity reduction are very promising. Based on the reviewed literature, recommendations are made for future research activities.

Wind tunnel studies on spray deposition on leaves of tree species used for windbreaks and exposure of honey bees

A wind tunnel study was conducted to determine pesticide deposition on commonly used windbreak tree species used as spray drift barriers and associated exposure of honey bees. Although it has been known that windbreaks are effective in reducing chemical drift from agricultural applications, there is still an enormous information and data gap on details of the dependence of the mechanism on the biological materials of the barriers and on standardization of relevant assessment methods. Beneficial arthropods like honey bees are adversely affected by airborne drift of pesticides. A study was initiated by first establishing a wind tunnel to create a controlled environment for capture efficiency work. Suitable spray parameters were determined after a preliminary study to construct and develop a wind tunnel protocol. A tracer dye solution was sprayed onto the windbreak samples and honey bees located in the wind tunnel at various simulated wind speeds. Analysis of data from this work has shown that needle-like foliage of windbreak trees captures two to four times more spray than broad-leaves. In addition, it was determined that, at lower wind speeds, flying bees tend to capture slightly more spray than bees at rest.