The Hidden and External Costs of Pesticide Use

Landscape features support natural pest control and farm income when pesticide application is reduced

Future trajectories of agricultural productivity need to incorporate environmental targets, including the reduction of pesticides use. Landscape features supporting natural pest control (LF-NPC) offer a nature-based solution that can serve as a partial substitute for synthetic pesticides, thereby supporting future productivity levels. Here, we introduce a novel approach to quantify the contribution of LF-NPC to agricultural yields and its associated economic value to crop production in a broad-scale context. Using the European Union as case study, we combine granular farm-level data, a spatially explicit map of LF-NPC potential, and a regional agro-economic supply and market model. The results reveal that farms located in areas characterized by higher LF-NPC potential experience lower productivity losses in a context of reduced synthetic pesticides use. Our analysis suggests that LF-NPC reduces yield gaps on average by four percentage points, and increases income by a similar magnitude. These results highlight the significance of LF-NPC for agricultural production and income, and provide a valuable reference point for farmers and policymakers aiming to successfully invest in landscape features to achieve pesticides reduction targets.

A comprehensive review and perspective research in technology integration for the treatment of gaseous volatile organic compounds

Volatile organic compounds (VOCs) are harmful pollutants emitted from industrial processes. They pose a risk to human health and ecosystems, even at low concentrations. Controlling VOCs is crucial for good air quality. This review aims to provide a comprehensive understanding of the various methods used for controlling VOC abatement. The advancement of mono-functional treatment techniques, including recovery such as absorption, adsorption, condensation, and membrane separation, and destruction-based methods such as natural degradation methods, advanced oxidation processes, and reduction methods were discussed. Among these methods, advanced oxidation processes are considered the most effective for removing toxic VOCs, despite some drawbacks such as costly chemicals, rigorous reaction conditions, and the formation of secondary chemicals. Standalone technologies are generally not sufficient and do not perform satisfactorily for the removal of hazardous air pollutants due to the generation of innocuous end products. However, every integration technique complements superiority and overcomes the challenges of standalone technologies. For instance, by using catalytic oxidation, catalytic ozonation, non-thermal plasma, and photocatalysis pretreatments, the amount of bioaerosols released from the bioreactor can be significantly reduced, leading to effective conversion rates for non-polar compounds, and opening new perspectives towards promising techniques with countless benefits. Interestingly, the three-stage processes have shown efficient decomposition performance for polar VOCs, excellent recoverability for nonpolar VOCs, and promising potential applications in atmospheric purification. Furthermore, the review also reports on the evolution of mathematical and artificial neural network modeling for VOC removal performance. The article critically analyzes the synergistic effects and advantages of integration. The authors hope that this article will be helpful in deciding on the appropriate strategy for controlling interested VOCs.

Prioritizing resource allocation to reduce adverse effects of pesticide risk for endangered species

The use of pesticides promotes food security because of the multiple benefits it brings to agriculture, such as reduction in crop losses. However, the use of pesticides can be potentially harmful to non-target species. In the U.S., the Environmental Protection Agency regulates the use of pesticides to manage the risks associated with these agents and to protect species under the Endangered Species Act. As part of these regulations, pesticides must be registered and then reviewed every 15 years to ensure the use conditions are updated with the best available data. The registration and review process can invoke corrective measures to ensure protection of endangered species. However, the registration review process is highly resource and time consuming. There is currently a backlog of unreviewed pesticides, leaving a large quantity of pesticides without updated use conditions to protect species. Identifying ways to streamline this process is urgently needed. We develop a sequencing approach to address the risk assessment bottleneck in the pesticide registration and review process and identify species that would benefit most from detailed assessments. We then demonstrate the magnitude of potential efficiencies using this sequencing process for 61 terrestrial listed species in the state of California. Our results show a consistent ranking of listed species according to their relative benefits from assessment, with 90 % of the species being robustly classified across scenarios in the sensitivity analysis. We found that prioritizing the assessment of a small group of species could potentially result in high conservation benefits, and identify species in need of more detailed data for a robust sequencing. We examine how a sequencing approach can guide decisions about what species might benefit most from different levels of assessment. Our results demonstrate the conservation benefits of employing a sequencing approach to prioritize the allocation of limited resources for endangered species.

The Economic Analyses of the Drosophila suzukii's Invasions: A Mini-review

The objective of this paper is to bring to the fore the type of economic analyses that have been carried out on the invasion of the Drosophila suzukii Matsumura (Diptera: Drosophilidae) and what has been learned. The analysis is limited to the original research articles published in peer-reviewed journals and book chapters. A total of 20 relevant studies are identified. The studies are analysed based on their main purpose, which is either economic impact assessment or economic evaluation of management programmes. The analysis also considers the key methodological points highlighted in recent reviews of the economic literature on alien invasive species. Over time, the focus of these studies has gradually shifted from raising awareness of the magnitude of the impact, particularly on agricultural production, to supporting the decision-making process concerning effective pest management. Most studies have been conducted from a private perspective, measuring private costs and providing guidance to the industry. However, some papers include, or focus on, the societal costs caused by the invasions of D. suzukii. This review has found few impact studies in the recently invaded areas and no economic evaluation of management programmes. There are not only geographical areas, but also themes that need more attention and analysis in the economic studies on D. suzukii. Assessing the economic effectiveness of integrated pest management programmes in specific settings, included the Latin American countries, is crucial.

Reducing eggs on eggplant: a common naturally emitted plant volatile could replace insecticides in the 'king of vegetables'

This article is a Commentary on Ghosh et al. (2023), 240: 1259–1274.

Modeling the Impact of Proportion, Sowing Date, and Architectural Traits of a Companion Crop on Foliar Fungal Pathogens of Wheat in Crop Mixtures

Diversification of cropping systems is a lever for the management of epidemics. However, most research to date has focused on cultivar mixtures, especially for cereals, even though crop mixtures can also improve disease management. To investigate the benefits of crop mixtures, we studied the effect of different crop mixture characteristics (i.e., companion proportion, sowing date, and traits) on the protective effect of the mixture. We developed a SEIR (Susceptible, Exposed, Infectious, Removed) model of two damaging wheat diseases (Zymoseptoria tritici and Puccinia triticina), which were applied to different canopy components, ascribable to wheat and a theoretical companion crop. We used the model to study the sensitivity of disease intensity to the following parameters: wheat-versus-companion proportion, companion sowing date and growth, and architectural traits. For both pathogens, the companion proportion had the strongest effect, with 25% of companion reducing disease severity by 50%. However, changing companion growth and architectural traits also significantly improved the protective effect. The effect of companion characteristics was consistent across different weather conditions. After decomposing the dilution and barrier effects, the model suggested that the barrier effect is maximized for an intermediate proportion of companion crop. Our study thus supports crop mixtures as a promising strategy to improve disease management. Future studies should identify real species and determine the combination of host and companion traits to maximize the protective effect of the mixture. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

No life-history cost of tebufenozide resistance in the smaller tea tortrix moth

BACKGROUND

Tebufenozide is widely used to control populations of the smaller tea tortrix, Adoxophyes honmai. However, A. honmai has evolved resistance such that straightforward pesticide application is an untenable long-term approach for population control. Evaluating the fitness cost of resistance is key to devising a management strategy that slows the evolution of resistance.

RESULTS

We used three approaches to assess the life-history cost of tebufenozide resistance with two strains of A. honmai: a tebufenozide-resistant strain recently collected from the field in Japan and a susceptible strain that has been maintained in the laboratory for decades. First, we found that the resistant strain with standing genetic variation did not decline in resistance in the absence of insecticide over four generations. Second, we found that genetic lines that spanned a range of resistance profiles did not show a negative correlation between their LD₅₀ , the dosage at which 50 % of individuals died, and life-history traits that are correlates of fitness. Third, we found that the resistant strain did not manifest life-history costs under food limitation. Our crossing experiments indicate that the allele at an ecdysone receptor locus known to confer resistance explained much of the variance in resistance profiles across genetic lines.

CONCLUSION

Our results indicate that the point mutation in the ecdysone receptor, which is widespread in tea plantations in Japan, does not carry a fitness cost in the tested laboratory conditions. The absence of a cost of resistance and the mode of inheritance have implications for which strategies may be effective in future resistance management efforts. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Glyphosate affects the susceptibility of non-target native plant species according to their stage of development and degree of exposure in the landscape

Unsustainable agriculture is producing a great socio-ecological transformation in Latin America because it has expanded into areas occupied by native forests. Glyphosate is the most widely used herbicide, with severe ecotoxicological effects on non-target organisms. The aim of this study was to determine the effects of glyphosate on seedlings of 24 non-target herbaceous and non-herbaceous plant species present in forest relicts of Argentine Chaco. The effects of a gradient of glyphosate doses (525, 1050, 2100, 4200, and 8400 g ai/ha) were measured in seedlings of each species under greenhouse conditions. Seedlings were grown from seeds collected from native forest fragments of different sizes (assuming three different degrees of historical exposure to glyphosate in the landscape). Doses were applied at different stages of seedling development (five- and ten-weeks after emergence), and phytotoxicity, growth reduction, and sensitivity were measured. Glyphosate produced lethal or sublethal effects in all 24 species, some of which were very sensitive (>60 % of the species presented strong to severe growth reduction with ¼ of the dose used on crops). The greatest toxicological effects were related to early stage of development, herbaceous species, and low historical exposure to glyphosate. According to the species sensitivity distribution, the drift-dose to protect 95 % of the plant species that occur in larger forest fragments should not exceed 5 % of the dose commonly used on crops. These results suggest that the current weed management linked to glyphosate-resistant crops could lead to a gradual loss of biodiversity in the landscape. Concurrently, selection of glyphosate-tolerant biotypes in some non-target species could represent a very problematic cycle for the current model of industrial agriculture. Some alternatives for weed control are proposed.

Antifungal alternation can be beneficial for durability but at the cost of generalist resistance

The evolution of resistance to pesticides is a major burden in agriculture. Resistance management involves maximizing selection pressure heterogeneity, particularly by combining active ingredients with different modes of action. We tested the hypothesis that alternation may delay the build-up of resistance not only by spreading selection pressure over longer periods, but also by decreasing the rate of evolution of resistance to alternated fungicides, by applying an experimental evolution approach to the economically important crop pathogen Zymoseptoria tritici. Our results show that alternation is either neutral or slows the overall resistance evolution rate, relative to continuous fungicide use, but results in higher levels of generalism in evolved lines. We demonstrate that the nature of the fungicides, and therefore their relative intrinsic risk of resistance may underly this trade-off, more so than the number of fungicides and the rhythm of alternation. This trade-off is also dynamic over the course of resistance evolution. These findings open up new possibilities for tailoring resistance management effectively while optimizing interplay between alternation components.

Environmental and human health impacts of volatile organic compounds: A perspective review

Volatile organic compounds (VOCs) are synthetic chemicals that are broadly used in the production of numerous day-to-day products for residential and commercial-based applications. VOCs are naturally occurring in the environment; however, average annual emissions of man-made volatile organic compounds may have increased dramatically in recent decades. Although many factors were attributed to influencing volatile compounds' emission, only mankind's activities are mainly proclaimed. Since vehicle and industrial pollution are mounting for years and years, urban areas are highly prone to the impacts of VOCs. Generally, volatile compounds are highly spontaneous and readily react with the particles of ambiance and produce a polluted atmosphere through several physical and chemical reactions. Though the volatile compounds play an indispensable role in the manufacture and maintaining the stability of many products, the health impacts associated with their prolonged exposure are gaining attention as recent research reports underline the influence of a wide range of diseases and disorders. Likewise, since the modern way of life applies a lot of day-to-day chemicals, it is imperative to spread a wide knowledge and safety aspects about these chemicals so that people of a wide category can implement preventive measures according to their exposure and living style. In this context, the review article attempts to shed light on past and current updates concerning the relationship between VOCs exposure and environmental and human health impacts.

Epigenetic regulations as drivers of insecticide resistance and resilience to climate change in arthropod pests

Arthropod pests are remarkably capable of rapidly adapting to novel forms of environmental stress, including insecticides and climate change. The dynamic interplay between epigenetics and genetics explains the largely unexplored reality underlying rapid climatic adaptation and the development of insecticide resistance in insects. Epigenetic regulation modulates gene expression by methylating DNA and acetylating histones that play an essential role in governing insecticide resistance and adaptation to climate change. This review summarises and discusses the significance of recent advances in epigenetic regulation that facilitate phenotypic plasticity in insects and their symbiotic microbes to cope with selection pressure implied by extensive insecticide applications and climate change. We also discuss how epigenetic changes are passed on to multiple generations through sexual recombination, which remains enigmatic. Finally, we explain how these epigenetic signatures can be utilized to manage insecticide resistance and pest resilience to climate change in Anthropocene.

Genetically Modified (GM) Crop Use 1996-2020: Environmental Impacts Associated with Pesticide Use CHANGE

This paper assesses the environmental impacts associated with changes in pesticide use with GM crops at a global level. The main technologies impacting on pesticide use have been crops modified to be tolerant to specific herbicides so as to facilitate improved weed control and crops resistant to a range of crop insect pests that otherwise damage crops or typically require the application of insecticides to control them. Over the 24 year period examined to 2020, the widespread use of GM insect resistant and herbicide tolerant seed technology has reduced pesticide application by 748.6 million kg (-7.2%) of active ingredient and, as a result, decreased the environmental impact associated with insecticide and herbicide use on these crops (as measured by the indicator, the Environmental Impact Quotient (EIQ)) by a larger 17.3% between 1996 and 2020. The technology that has delivered the largest change in pesticide use has been insect resistant cotton, where a 339 million kg of active ingredient saving has occurred and the associated environmental impact (as measured by the EIQ indicator) has fallen by about a third.

The social costs of pesticide use in France

The modern agricultural production system relies heavily on the use of synthetic pesticides, but over the course of recent decades various concerns have been raised on the associated negative externalities touching a variety of dimensions, such as human health and the environment. Yet, the magnitude of those effects is still unclear and data availability is scattered and heterogenous across dimensions, regions, and time. The public sector is called upon to develop and implement strategies to face those externalities and their associated social costs. This study aims to provide an assessment of social costs of pesticides in France in the prospect of an integration to the public budget spending, helping public authorities to identify financial flows of public funding with an impact perspective, within a methodological framework based on the social norms at the core of the public system. The results show that the social costs attributable to synthetic pesticide use in France amounted to 372 million euros, of which environmental costs are estimated at least at 291.5 million euros, health costs at least at 48.5 million euros, regulation at least at 31.9 million euros and public financial support to the sector at least at 0.4 million euros. For comparison, this total value of social costs represents more than 10% of the annual budget in 2017 of the French Ministry of Agriculture and Food (3,587 million euros). The analysis can be used as a monitoring indicator for the implementation of public policies in the context of the growing social and environmental issues they face.

Sustainable Consumption: Will They Buy It Again? Factors Influencing the Intention to Repurchase Organic Food Grain

Global consumption trends point to rising demand for organic food as people become more health-conscious. The factors that people consider while making initial organic purchases have been discussed at length. However, the published research is scant about the factors that affect consumers’ propensity to repurchase organic goods. The present research fills this gap by focusing on what influences consumers’ decisions to repurchase organic grain. The Stimulus-Organism-Response (S-O-R) theory and the Theory of Planned Behaviour are the theoretical foundations of the present investigation. The consumer’s attitude toward organic grains and their desire to repurchase organic grains are influenced by health consciousness and previous experience. The repurchase intent was determined to be controlled by the buyer’s willingness to pay and their level of trust in the organic grain. This cross-sectional study collected the necessary data from five chosen urban centres in India. Smart PLS 3.2.9 was used to analyse the gathered data from 463 respondents. According to the findings, health consciousness and past experience favourably influence attitudes and repurchase intent. The trust that consumers have built up in organic grain as a result of past experiences is what drives their desire to make more purchases. Willingness to pay significantly controls and impacts the inclination to repurchase. The association between health consciousness and repurchase intention is partially mediated by attitude, as is the relationship between past experience and repurchase intention. The relationship between health consciousness and the desire to repurchase is partially mediated by the willingness to pay.

Pest management in future climates: Warming reduces physical weed management effectiveness

Climate change alters many aspects of weed performance and may also alter the effectiveness of management practices to control pests. Despite this concern, entire categories of widely used management practices, such as physical control, remain understudied in this context. We conducted a field experiment growing the invasive pest musk thistle (Carduus nutans) at ambient and experimentally elevated temperatures. We tested mowing management strategies that varied in the timing of a single mowing event relative to thistles' stem elongation phenology and compared these with an unmowed control. Results from this experiment informed demographic models to project population growth rates for different warming/mowing scenarios. Compared to plants grown under ambient conditions, warmed thistles were more likely to survive the same mowing treatment, flowered earlier in the season, grew to taller heights, and produced more flowering capitula. Proportional reductions in plant height and capitulum production caused by mowing were smaller under warming. Warming did not change the relative ranking of mowing treatments; mowing late in the growing season (2 weeks after individuals first reached a height of 40 cm) was most effective at ambient temperatures and under warming. Warming caused significant increases in projected local population growth rate for all mowing treatments. For invasive musk thistle, warmed individuals outperformed individuals grown at ambient temperatures across all the mowing treatments we considered. Our results suggest that to achieve outcomes comparable to those attainable at today's temperatures, farmers will need to apply supplemental management, possibly including additional mowing effort or alternative practices such as chemical control. We recommend that scientists test management practices under experimental warming, where possible, and that managers monitor ongoing management to identify changes in effectiveness. Information about changes in managed weeds' mortality, fecundity, and phenology can then be used to make informed decisions in future climates.

Genome-Wide Transcriptomic Analysis of the Effects of Infection with the Hemibiotrophic Fungus Colletotrichum lindemuthianum on Common Bean

Bean anthracnose caused by the hemibiotrophic fungus Colletotrichum lindemuthianum is one of the most important diseases of common bean (Phaseolus vulgaris) in the world. In the present study, the whole transcriptome of common bean infected with C. lindemuthianum during compatible and incompatible interactions was characterized at 48 and 72 hpi, corresponding to the biotrophy phase of the infection cycle. Our results highlight the prominent role of pathogenesis-related (PR) genes from the PR10/Bet vI family as well as a complex interplay of different plant hormone pathways including Ethylene, Salicylic acid (SA) and Jasmonic acid pathways. Gene Ontology enrichment analysis reveals that infected common bean seedlings responded by down-regulation of photosynthesis, ubiquitination-mediated proteolysis and cell wall modifications. In infected common bean, SA biosynthesis seems to be based on the PAL pathway instead of the ICS pathway, contrarily to what is described in Arabidopsis. Interestingly, ~30 NLR were up-regulated in both contexts. Overall, our results suggest that the difference between the compatible and incompatible reaction is more a question of timing and strength, than a massive difference in differentially expressed genes between these two contexts. Finally, we used RT-qPCR to validate the expression patterns of several genes, and the results showed an excellent agreement with deep sequencing.

Development and Evaluation of a Prototype Self-Propelled Crop Sprayer for Agricultural Sustainability in Small Farms

In most Asian countries, farmers have smallholdings ranging from one to two hectares. The tractor-mounted boom sprayers cannot practically be used in small size farms with divided plots and complex terrain. To cope with these issues, a prototype self-propelled crop sprayer was developed, including a 20-hp engine, 300 L liquid tank, and hydraulically-controlled spray boom with eight hollow cone nozzles. The spray symmetry of the hollow cone nozzle was evaluated under four pressures (2.5, 3, 3.5, and 4 bar) in the laboratory. The operating parameters of the sprayer, such as forward speed (4, 6, and 8 km h−1), spray height (40, 55, and 70 cm), and pressure (3, 5, and 7 bar) were optimized by measuring three spray characteristics including droplet density, coverage percentage, and Volume Median Diameter (VMD) in the cotton field. The results revealed that the nozzle spray was symmetrical at 2.5 and 3 bar pressure as the R2 value was higher than 0.96. The field test result showed that in all treatments, treatments T14 (6 km h−1, 55 cm, 5 bar) and T22 (8 km h−1, 55 cm, 3 bar) were suitable for spraying medium-to-low concentration solution (post-emergence herbicides and fungicides) and high concentration solution (insecticides and pre-emergence herbicides), respectively. The spray characteristics at treatments T14 and T22 were 64.7 droplets cm−2, 26.7%, 230 µm, and 39 droplets cm−2, 14.9%, and 219.8 µm respectively. The field efficiency of the sprayer was 61%. The spraying cost per unit area was 55–64% less compared to manual labor cost. In conclusion, a prototype self-propelled crop sprayer is an efficient and environment-friendly technology for small farms. Operating the sprayer at the optimal parameters also saves operational costs and time.

Engineered resistance and risk assessment associated with insecticidal and weeds resistant transgenic cotton using wister rat model

Stacking multiple genes into cotton crop to cop up multiple biotic stresses such as insects and weeds is a promising tool to save crop from losses. Transgenic cotton variety, VH-289, with double Bt and cp4EPSPS genes under the control of 35S promoter was used for the expression analyses and biosafety studies. The transgenic cotton plants were screened through PCR amplification of fragments, 1.7 kb for Cry1Ac, 582 bp for Cry2A and 250 bp for cp4EPSPS; which confirmed the presence of all genes transformed in transgenic cotton. The Cry1Ac + Cry2A and cp4EPSPS proteins were quantified through ELISA in transgenic cotton plants. The Glyphosate assay performed by spraying 1900 mL per acre of glyphosate Roundup further confirmed complete survival of transgenic cotton plants as compared to the non-transgenic cotton plants and all weeds. Similarly, insect infestation data determined that almost 99% insect mortality was observed in controlled field grown transgenic cotton plants as compared to the non-transgenic control plants. Evaluation of effect of temperature and soil nutrients availability on transgene expression in cotton plants was done at two different cotton growing regions, Multan and Lahore, Pakistan and results suggested that despite of higher temperature in Multan field, an increased level of Cry and cp4EPSPS proteins was recorded due to higher soil organic matter availability compared to Lahore field. Before commercialization of any transgenic variety its biosafety study is mandatory so, a 90 days biosafety study of the transgenic cotton plants with 40% transgenic cottonseeds in standard diet showed no harmful effect on wister rat model when studied for liver function, renal function and serum electrolyte.

Remobilization of pollutants during extreme flood events poses severe risks to human and environmental health

While it is well recognized that the frequency and intensity of flood events are increasing worldwide, the environmental, economic, and societal consequences of remobilization and distribution of pollutants during flood events are not widely recognized. Loss of life, damage to infrastructure, and monetary cleanup costs associated with floods are important direct effects. However, there is a lack of attention towards the indirect effects of pollutants that are remobilized and redistributed during such catastrophic flood events, particularly considering the known toxic effects of substances present in flood-prone areas. The global examination of floods caused by a range of extreme events (e.g., heavy rainfall, tsunamis, extra- and tropical storms) and subsequent distribution of sediment-bound pollutants are needed to improve interdisciplinary investigations. Such examinations will aid in the remediation and management action plans necessary to tackle issues of environmental pollution from flooding. River basin-wide and coastal lowland action plans need to balance the opposing goals of flood retention, catchment conservation, and economical use of water.

Monitoring of level of mean concentration and toxicity equivalence (TEQ) of polychlorinated biphenyls (PCBs) in selected vegetables, beans and grains in khanewal and multan, Pakistan

Contamination of food chain by Polychlorinated biphenyls through use of pesticides, electric and industrial waste poses human health risk. In previous studies, PCB species were stated as endocrine disrupting pollutants and showed toxic health effects like cancerous and noncancerous in animals. The aim of this study was to investigate the levels of PCBs and its toxicity equivalence in food item from plant source to evaluate the health risk in Khanewal and Multan, Pakistan. Samples were collected and processed for further analysis of PCB species through GC/MS after extraction and clean up. The mean concentrations of PCBs ranged as 2.71–151.67 ng/g in beans and grains and 2.30–97.00 ng/g dry weight in vegetables and were lower than 200–3000 ng/g PCBs recommended by FDA tolerance level for all foods. The mean concentrations of two NDL-PCB species detected in all vegetables, beans and grains except S.indicum and T.aestivum were lower than maximum allowable concentration of non-dioxin like PCBs i.e. 40ngg⁻¹ reported by European Commission. Mean TEQ of sum of 14 PCB species ranged as 1.52–5.91 ng-WHO-TEQg⁻¹ in vegetables and 1.46–10.04 ng-WHO-TEQg⁻¹ in beans and grains. The present study concluded that the mean concentrations and mean TEQs of PCB species in most of the vegetables, beans and grains were found safe but due to higher consumption rate of some vegetables and grains, posed the moderate level of risk for human health. This study emphasizes on an implement of the strict rules regarding the use of restricted chemicals to diminish the effluence in food chains. Current research will be useful in up gradation of effective measures to reduce the poisonous contribution of PCB sources and the sustainability of terrestrial ecosystem in the country.

Do pesticides promote or hinder sustainability in agriculture? The challenge of sustainable use of pesticides in modern agriculture

Sustainable agriculture aims to meet the food needs of the growing world population while ensuring minimal impact on the environment and humans as well as productivity. Although pesticides represent the backbone of the agri-food sector in its endeavor to secure food production their application is perceived by many as an obstacle towards the achievement of sustainability; the main concerns are linked with their adverse effects on human health and the environment. Τhis review aims to present the status of chemical plant protection and provide insights into the use of pesticides within the context of sustainable agriculture. It mainly focuses on the strengthened legislation frameworks, which especially in the European Union and the United States of America ensure the placement in the market of pesticides with acceptable toxicological and environmental profiles without compromising crop production. Furthermore, the implementation of Integrated Pest Management principles plays a key role in the sustainable use of pesticides. The stringent regulatory requirements have resulted in the dramatic increase of the associated effort and costs in pesticide research and development (R&D) of improved products. Nevertheless, the investment of leading agrochemical companies in the R&D of new pesticides remains high. All the above set the ground for the sustainable use of pesticides in crop production while their successful application remains a challenge.

Characterization of cellular, biochemical and genomic features of the diazotrophic plant growth-promoting bacterium Azospirillum sp. UENF-412522, a novel member of the Azospirillum genus

Given their remarkable beneficial effects on plant growth, several Azospirillum isolates currently integrate the formulations of various commercial inoculants. Our research group isolated a new strain, Azospirillum sp. UENF-412522, from passion fruit rhizoplane. This isolate uses carbon sources that are partially distinct from closely-related Azospirillum isolates. Scanning electron microscopy analysis and population counts demonstrate the ability of Azospirillum sp. UENF-412522 to colonize the surface of passion fruit roots. In vitro assays demonstrate the ability of Azospirillum sp. UENF-412522 to fix atmospheric nitrogen, to solubilize phosphate and to produce indole-acetic acid. Passion fruit plantlets inoculated with Azospirillum sp. UENF-41255 showed increased shoot and root fresh matter by 13,8% and 88,6% respectively, as well as root dry matter by 61,4%, further highlighting its biotechnological potential for agriculture. We sequenced the genome of Azospirillum sp. UENF-412522 to investigate the genetic basis of its plant-growth promotion properties. We identified the key nif genes for nitrogen fixation, the complete PQQ operon for phosphate solubilization, the acdS gene that alleviates ethylene effects on plant growth, and the napCAB operon, which produces nitrite under anoxic conditions. We also found several genes conferring resistance to common soil antibiotics, which are critical for Azospirillum sp. UENF-412522 survival in the rhizosphere. Finally, we also assessed the Azospirillum pangenome and highlighted key genes involved in plant growth promotion. A phylogenetic reconstruction of the genus was also conducted. Our results support Azospirillum sp. UENF-412522 as a good candidate for bioinoculant formulations focused on plant growth promotion in sustainable systems.

The role of machine learning method in the synthesis and biological ınvestigation of heterocyclic compounds

Machine learning (ML) methods have attracted increasing interest in chemistry as in all fields of science in recent years. This method is of great importance for the design of targeted bioactive compounds, especially by avoiding loss of time, money, and chemicals. There are lots of online web-based platforms such as LibSVM and OCHEM for the application of ML methods. In this paper, it has been examined the literature data on the activity predictions of heterocyclic compounds, biological activity results such as antiurease, HIV-1 Integrase, E. Coli DNA Gyrase B, and antifungal, pharmacophore-based studies, synthesis, and finding possible inhibitors using different machine learning methods.

Encapsulation of B. bassiana in Biopolymers: Improving Microbiology of Insect Pest Control

The fungus Beauveria bassiana is widely used for pest control; however, biostability and dispersion for broth pulverization are limiting factors for its application in the field. In this context, formulation techniques such as microencapsulation are viable alternatives. The aim of this work is to optimize B. bassiana formulations by spray dryer and evaluate its stability and biological activity against Spodoptera cosmioides compared to ionic gelatinization formulations. The fungus was biocompatible with all evaluated biopolymers (lignin, cellulose, starch, humic substances, and alginate). The encapsulation by spray drying was optimized by factorial design in an inlet and outlet air temperature of 120°C and 68°C, respectively; aspirator rate of 35 m³·h⁻¹, feed flow rate of 12 mL·min⁻¹; and drying gas flow at 35 L·h⁻¹. The ionic gelation capsules were obtained using a 0.5% quantity of conidia in a 1% sodium alginate solution dropped into a 0.5 mol·L⁻¹ CaCl₂ solution using a peristaltic pump. Spray drying provided smaller microcapsules than those by ionic gelation. Both techniques produced more stable conidia when exposed to temperature and UV-radiation than non-formulated B. bassiana. The formulations prepared by spray drying showed gains at aqueous dispersion. Biological assays against Spodoptera cosmioides showed a mortality rate of up to 90%. These results demonstrate the suitability of encapsulating B. bassiana conidia stably in aqueous dispersion without loss of viability and virulence.

Gene drive strategies of pest control in agricultural systems: Challenges and opportunities

Recent advances in gene-editing technologies have opened new avenues for genetic pest control strategies, in particular around the use of gene drives to suppress or modify pest populations. Significant uncertainty, however, surrounds the applicability of these strategies to novel target species, their efficacy in natural populations and their eventual safety and acceptability as control methods. In this article, we identify issues associated with the potential use of gene drives in agricultural systems, to control pests and diseases that impose a significant cost to agriculture around the world. We first review the need for innovative approaches and provide an overview of the most relevant biological and ecological traits of agricultural pests that could impact the outcome of gene drive approaches. We then describe the specific challenges associated with using gene drives in agricultural systems, as well as the opportunities that these environments may offer, focusing in particular on the advantages of high-threshold gene drives. Overall, we aim to provide a comprehensive view of the potential opportunities and the remaining uncertainties around the use of gene drives in agricultural systems.

Application of the Danish pesticide load indicator to arable agriculture in the United Kingdom

Pesticides are an important component of worldwide agriculture systems and have contributed to significant increases in crop quality and yields and therefore to food security. However, despite their societal benefits, pesticides can be hazardous to humans and the environment. Therefore, effective pesticide polices are needed that balance the societal and economic benefits with the unintentional and undesirable environmental and health impacts. As a result, there has been consistent policy interest in pragmatic and practical techniques that are suitable for assessing the environmental and human health implications of agricultural pesticide use from a national perspective for assisting in the development of policy initiatives and for communicating policy outcomes to the public. The work described herein explored the appropriateness of the Danish Pesticide Load Indictor for assessing agricultural pesticides applied in the United Kingdom from 2016 and 2018. The findings for the two datasets appear broadly comparable, suggesting that the overall environmental load from pesticides on the U.K. environment remained relatively constant during this period. Regional differences in environmental load and the major contributing substances were identified. Where large differences between the two years were seen, regulatory interventions appear to have been the cause. Overall, the indicator behaves as expected and appears to be sufficiently responsive to changes in pesticide use. However, various concerns were identified that may lead to modifications in how the indicator is calculated and what parameters are included to make it better able to deliver U.K. policy objectives.

Bacillus Cyclic Lipopeptides Iturin and Fengycin Control Rice Blast Caused by Pyricularia oryzae in Potting and Acid Sulfate Soils by Direct Antagonism and Induced Systemic Resistance

Rice monoculture in acid sulfate soils (ASSs) is affected by a wide range of abiotic and biotic constraints, including rice blast caused by Pyricularia oryzae. To progress towards a more sustainable agriculture, our research aimed to screen the biocontrol potential of indigenous Bacillus spp. against blast disease by triggering induced systemic resistance (ISR) via root application and direct antagonism. Strains belonging to the B. altitudinis and B. velezensis group could protect rice against blast disease by ISR. UPLC-MS and marker gene replacement methods were used to detect cyclic lipopeptide (CLiP) production and construct CLiPs deficient mutants of B. velezensis, respectively. Here we show that the CLiPs fengycin and iturin are both needed to elicit ISR against rice blast in potting soil and ASS conditions. The CLiPs surfactin, iturin and fengycin completely suppressed P. oryzae spore germination resulting in disease severity reduction when co-applied on rice leaves. In vitro microscopic assays revealed that iturin and fengycin inhibited the mycelial growth of the fungus P. oryzae, while surfactin had no effect. The capacity of indigenous Bacillus spp. to reduce rice blast by direct and indirect antagonism in ASS conditions provides an opportunity to explore their usage for rice blast control in the field.

Improving pest monitoring networks using a simulation-based approach to contribute to pesticide reduction

Conventional pest management mainly relies on the use of pesticides. However, the negative externalities of pesticides are now well known. More sustainable practices, such as Integrated Pest Management, are necessary to limit crop damage from pathogens, pests and weeds in agroecosystems. Reducing pesticide use requires information to determine whether chemical treatments are really needed. Pest monitoring networks (PMNs) are key contributors to this information. However, the effectiveness of a PMN in delivering relevant information about pests depends on its spatial sampling resolution and its memory length. The trade-off between the monitoring efforts and the usefulness of the information provided is highly dependent on pest ecological traits, the damage they can cause (in terms of crop losses), and economic drivers (production costs, agriculture product prices and incentives). Due to the high complexity of optimising PMNs, we have developed a theoretical model that belongs to the family of Dynamic Bayesian Networks in order to compare several PMNs performances. This model links the characteristics of a PMN to treatment decisions and the resulting pest dynamics. Using simulation and inference tools for graphical models, we derived the proportion of impacted fields, the number of pesticide treatments and the overall gross margins for three types of pest with contrasting levels of endocyclism. The term "endocyclic" refers to an organism whose development is mostly restricted to a field and highly depends on the inoculum present in the considered field. The presence of purely endocyclic pests at a given time increases the probability of reoccurrence. Conversely, slightly endocyclic pests have a low persistence. The simulation analysis considered ten scenarios: an expected margin-based strategy with a spatial resolution of four PMNs and two memory lengths (one year or eight years), as well as two extreme crop protection strategies (systematic treatments on all fields and systematic no treatment). For purely and mainly endocyclic pests (e.g. soil-borne pathogens and most weeds, respectively), we found that increasing the spatial resolution of PMNs made it possible to significantly decrease the number of treatments required for pest control. Taking past observations into account was also effective, but to a lesser extent. PMN information had virtually no influence on the control of non-endocyclic pests (such as flying insects or airborne plant pathogens) which may be due to the spatial coverage addressed in our study. The next step is to extend the analysis of PMNs and to integrate the information generated by PMNs into sustainable pest management strategies, both at the field and the landscape level.

Biological Control of Aphis spiraecola (Hemiptera: Aphididae) Using Three Different Flowering Plants in Apple Orchards

Increasing the biodiversity of agroecosystems can increase populations of natural enemies that are useful for pest control. Orchards often have a low diversity of plant species, which is not conducive to maintaining ecosystem functions and services. However, additional flowering plants could provide natural enemies with beneficial resources. To assess the ability of flowering plants to attract predators and increase the biological control of Aphis spiraecola Patch, we established individual plots of three different flowering plant species with sequential bloom periods between the rows of apple orchard. These plants attracted predators such as Coccinellidae, Syrphidae, and Chrysopidae when flowering. The density of predators on trees in the three flowering plant plots was significantly higher than that in the control, whereas the density of aphids on trees in Orychophragmus violaceus (L.) O. E. Schulz (Rhoeadales: Brassicaceae) and Cnidium monnieri (Linn.) Cuss. (Apiales: Apiaceae) plots were significantly lower than that in control. The density of aphids on trees in Calendula officinalis L. (Asterales: Asteraceae) plots was significantly lower than in other plots at second peak period. There was a significant negative correlation between the population of aphids and predators on trees at peak of aphids. Cage exclusion tests showed that the biocontrol services index (BSI) of O. violaceus was highest (32.7%) on 24 May, and the BSI of C. monnieri was highest (47.6%) on 7 June. Our results suggest that the temporal combination of different flowering plants could provide useful effective biocontrol to management pest in orchard.

Recent advances in soil microbial fuel cells for soil contaminants remediation

The cost-effective and eco-friendly approaches are needed for decontamination of polluted soils. The bio-electrochemical system, especially microbial fuel cells (MFCs) offer great promise as a technology for remediation of soil, sediment, sludge and wastewater. Recently, soil MFCs (SMFCs) have been attracting increasing amounts of interest in environmental remediation, since they are capable of providing a clean and inexhaustible source of electron donors or acceptors and can be easily controlled by adjusting the electrochemical parameters. In this review, we comprehensively covered the principle of SMFCs including the mechanisms of electron releasing and electron transportation, summarized the applications for soil contaminants remediation by SMFCs with highlights on organic contaminants degradation and heavy metal ions removal. In addition, the main factors that affected the performance of SMFCs were discussed in details which would be helpful for performance optimization of SMFCs as well as the efficiency improvement for soil remediation. Moreover, the key issues need to be addressed and future perspectives are presented.

Secondary Metabolites from Artemisia Genus as Biopesticides and Innovative Nano-Based Application Strategies

The Artemisia genus includes a large number of species with worldwide distribution and diverse chemical composition. The secondary metabolites of Artemisia species have numerous applications in the health, cosmetics, and food sectors. Moreover, many compounds of this genus are known for their antimicrobial, insecticidal, parasiticidal, and phytotoxic properties, which recommend them as possible biological control agents against plant pests. This paper aims to evaluate the latest available information related to the pesticidal properties of Artemisia compounds and extracts and their potential use in crop protection. Another aspect discussed in this review is the use of nanotechnology as a valuable trend for obtaining pesticides. Nanoparticles, nanoemulsions, and nanocapsules represent a more efficient method of biopesticide delivery with increased stability and potency, reduced toxicity, and extended duration of action. Given the negative impact of synthetic pesticides on human health and on the environment, Artemisia-derived biopesticides and their nanoformulations emerge as promising ecofriendly alternatives to pest management.

Agrochemical pesticide production, trade, and hazard: Narrowing the information gap in Colombia

Pesticides are a major tool for the intensification of agriculture, and helped to increase food, feed and biofuel production. Yet, there are persistent concerns about the negative effects of pesticides in human health and the environment, particularly in low and middle income countries (LMICs). Given the lack of information on pesticide exposure and hazard, Colombia exemplifies the need to narrow the information gap on pesticide risk in LMICs. We assessed pesticide hazard in Colombia based on the official toxicity categorization, compared it to more integral international standards, and identified main actions to narrow this information gap. Results showed that Colombia has been a relevant regional actor in pesticide production and trade, reaching almost 75 million kilogrammes and liters sold in 2016. Based on acute toxicity for humans, a quarter of the amount of pesticides sales and imports, and a third of the exports in 2016 ranged from moderately to extremenly toxic. The top-selling agrochemicals in 2016 (glyphosate with 14% of the total sales, chlorpyrifos 7.5% and mancozeb 6.9%) are also commonly used in other countries, reflecting a homogenized global industry. Compared to integral international categorizations, we found that for that year 63% of the pesticides sold with slightly acute toxicity are actually considered highly hazardous pesticides (HHP) for humans or the environment, evidencing the need to use a more integral hazard categorization in the country. Narrowing the information gap in pesticide use and associated risks demands a transparent process of knowledge creation and sharing, including funtional information and monitoring systems. This should be part of an integral assessment and regulation that better defines HHP, their production and trade to reduce pesticide risk while informing a transition towards sustainable food systems.

Biological Control of Chili Damping-Off Disease, Caused by Pythium myriotylum

Pythium myriotylum is a notorious soil-borne oomycete that causes post-emergence damping-off in chili pepper. Of various disease management strategies, utilization of plant growth promoting rhizobacteria (PGPR) in disease suppression and plant growth promotion is an interesting strategy. The present study was performed to isolate and characterize PGPR indigenous to the chili rhizosphere in Pakistan, and to test the potential to suppress the damping-off and plant growth promotion in chili. Out of a total of 28 antagonists, eight bacterial isolates (4a2, JHL-8, JHL-12, 1C2, RH-24, 1D, 5C, and RH-87) significantly suppressed the colony growth of P. myriotylum in a dual culture experiment. All the tested bacterial isolates were characterized for biochemical attributes, and 16S rRNA sequence based phylogenetic analysis identified these isolates as Flavobacterium spp., Bacillus megaterium, Pseudomonas putida, Bacillus cereus, and Pseudomonas libanensis. All the tested bacterial isolates showed positive test results for ammonia production, starch hydrolase (except 4a2), and hydrogen cyanide production (except 4a2 and 1D). All the tested antagonists produced indole-3-acetic acid (13.4–39.0 μg mL^–1), solubilized inorganic phosphate (75–103 μg mL^–1), and produced siderophores (17.1–23.7%) in vitro. All the tested bacterial isolates showed varying levels of susceptibility and resistance response against different antibiotics and all these bacterial isolates were found to be non-pathogenic to chili seeds and notably enhanced percentage seed germination, plumule, redical length, and vigor index over un-inoculated control. Additionally, under pathogen pressure, bacterization increased the defense related enzymes such as Peroxidase (PO), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) activates. Moreover, the treatment of chili seeds with these bacterial isolates significantly suppressed the damping-off caused by P. myriotylum and improved PGP traits compared to the control. In addition, a positive correlation was noticed between shoot, root length, and dry shoot and root weight, and there was a negative correlation between dry shoot, root weight, and seedling percentage mortality. These results showed that native PGPR possesses multiple traits beneficial to the chili plants and can be used to develop eco-friendly and effective seed treatment formulation as an alternative to synthetic chemical fungicides.

Physiological and morphoanatomical effects of glyphosate in Eugenia uniflora, a Brazilian plant species native to the Atlantic Forest biome

The herbicide glyphosate can cause severe ecotoxicological effects on non-target organisms. Eugenia uniflora L. (Myrtaceae) is very important for in situ environmental biomonitoring due to its wide distribution in the Atlantic Forest biome. Thus, this study aimed to evaluate the response of E. uniflora leaves to glyphosate. Eight-month-old plants were exposed to an aerial application of the herbicide at concentrations of 0, 144, 432, 864, and 1440 g a. e. ha-1 (grams of acid equivalent per hectare). Evaluations were performed on the 12th day after the glyphosate application (DAA). An accumulation of shikimic acid in the leaves of E. uniflora was observed. Glyphosate altered the photosynthetic parameters of the treated plants, with a drastic decrease in the photosynthetic rate, stomatal conductance, transpiration, and pigment content. There was an increase in Ci/Ca, lipid peroxidation, and electrolyte extravasation levels. Glyphosate also promoted ultrastructural, anatomical and visible damage to the E. uniflora leaves. Our findings indicate that glyphosate is phytotoxic to the native species E. uniflora at the tested doses. The presence of visible damage suggests that E. uniflora has remarkable potential as a bioindicator of glyphosate in the environment, making it a possible species for future biomonitoring projects.

Seed biopriming with cyanobacterial extracts as an eco-friendly strategy to control damping off caused by Pythium ultimum in seedbeds

This work highlights the ability of various cyanobacterial extracts from Anabaena spp., Tolypothrix spp., Nostoc or Trichormus, among others genera, to control the incidence of damping-off caused by Pythium ultimum in cucumber seedlings. Protocols applied aimed at the preliminary characterization of the cyanobacterial collection were very useful for predicting their phytotoxic, phytostimulating and biopesticidal capacity. First, the phytostimulatory or phytotoxic potential of a collection of 31 sonicated cyanobacterial extracts was analyzed by calculating the germination index in watercress seeds and the increase or loss of seedling weight. Likewise, the collection was characterized according to its ability to inhibit the growth of P. ultimum by dual culture bioassays and detached-leaf test. Finally, after selecting the most effective extracts, a preventive damping-off bioassay was performed based on cucumber seed biopriming. The strain SAB-M465 showed to be the most efficient strain against the in vitro growth of P. ultimum, while SAB-B912 was more discreet in this regard, but proved to be the most effective as a germination stimulator. Seed biopriming strategy with sonicated extracts of cyanobacteria revealed a remarkable promoter effect in the early stages of plant development, although only SAB-M465 was positioned as an effective control agent against damping-off caused by P. ultimum in cucumber seedbeds.

Growth Inhibition of Phytopathogenic Fungi and Oomycetes by Basidiomycete Irpex lacteus and Identification of its Antimicrobial Extracellular Metabolites

In dual culture confrontation assays, basidiomycete Irpex lacteus efficiently antagonized Fusarium spp., Colletotrichum spp., and Phytophthora spp. phytopathogenic strains, with growth inhibition percentages between 16.7-46.3%. Antibiosis assays evaluating the inhibitory effect of soluble extracellular metabolites indicated I. lacteus strain inhibited phytopathogens growth between 32.0-86.7%. Metabolites in the extracellular broth filtrate, identified by UPLC-QTOF mass spectrometer, included nine terpenes, two aldehydes, and derivatives of a polyketide, a quinazoline, and a xanthone, several of which had antifungal activity. I. lacteus strain and its extracellular metabolites might be valuable tools for phytopathogenic fungi and oomycete biocontrol of agricultural relevance.

Water footprint coupled economic impact assessment for maize production in China

Nowadays, agricultural production places an enormous burden on freshwater resources, and the environmental external cost caused by the restoration of water quality degradation has attracted great attention. Maize is regarded as one of the world's major food security crops, and China is the second-largest maize producer. Thus, this study conducts an impact-oriented water footprint coupled economic impact assessment to quantify the water-related environmental impacts and economic burden caused by China's maize production from 2008 to 2017. Results show that the overall damage to human health and ecosystem quality of China's maize production in 2017 were 4.32 × 10⁴ DALY and 4.62 × 10³ Species·yr, respectively. The total economic cost was $ 2.15 × 10¹¹, which included an internal cost of $ 5.99 × 10¹⁰ and external cost of $ 1.55 × 10¹¹. Key factor analysis demonstrates that diesel and fertilizer production dominated the reduction in ecological and external cost burdens. Direct water consumption and labor cost played leading roles in human health and internal cost, respectively. The spatiotemporal variation assessment indicates that Inner Mongolia and Heilongjiang were the hotspots for water footprint and economic impact assessment results after considering the yield factor. The national average water footprint and economic impact caused by producing 1 ton of maize showed an upward trend from 2008 to 2015, however, a significant decline transpired later. Overall, improving the resource efficiency (i.e., diesel and freshwater), scientific application of fertilizer and reducing labor input can further lessen the water footprint and economic impact of maize production. Developing the social environment can also generate indirect environmental and economic benefits to China's maize production.

Controlling Geminiviruses before Transmission: Prospects

Whitefly (Bemisia tabaci)-transmitted Geminiviruses cause serious diseases of crop plants in tropical and sub-tropical regions. Plants, animals, and their microbial symbionts have evolved complex ways to interact with each other that impact their life cycles. Blocking virus transmission by altering the biology of vector species, such as the whitefly, can be a potential approach to manage these devastating diseases. Virus transmission by insect vectors to plant hosts often involves bacterial endosymbionts. Molecular chaperonins of bacterial endosymbionts bind with virus particles and have a key role in the transmission of Geminiviruses. Hence, devising new approaches to obstruct virus transmission by manipulating bacterial endosymbionts before infection opens new avenues for viral disease control. The exploitation of bacterial endosymbiont within the insect vector would disrupt interactions among viruses, insects, and their bacterial endosymbionts. The study of this cooperating web could potentially decrease virus transmission and possibly represent an effective solution to control viral diseases in crop plants.

Role of Biocontrol Agents in Management of Corm Rot of Saffron Caused by Fusarium oxysporum

Saffron (Crocus sativus L.) is considered as one of the most expensive spices. Fusarium corm rot of saffron, caused by Fusarium oxysporum, is known to cause severe yield losses worldwide. In the present study, efficacy of biocontrol agents (Trichoderma asperellum, Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas putida, Bacillus stratosphericus, Bacillus pumilus, and Bacillus subtilis) along with a chemical fungicide, carbendazim, was evaluated for managing the corm rot of saffron. Under in vitro conditions, using dual culture and poison food techniques on potato dextrose agar, T. asperellum and carbendazim significantly reduced the mycelial growth of the pathogen F. oxysporum, with the inhibition of 62.76 and 60.27%, respectively, compared with control. Under field conditions, dipping of saffron corms in carbendazim and T. asperellum exhibited maximum reduction of 82.77 and 77.84%, respectively, in the disease incidence, during the first year of experiment. However, during the second year, maximum reduction in the incidence of corm rot (68.63%) was recorded with the T. asperellum. Moreover, the population density of F. oxysporum was also significantly reduced by 60 and 80.19% while using T. asperellum after 75 and 260 days of sowing of saffron corms, compared to its population before planting of corms. In case of growth promotion traits, such as sprouting and flowering, biocontrol treatments reduced the number of days (average) of sprouting and flower emergence after sowing, compared to control.

Unmanned aerial vehicles for biodiversity-friendly agricultural landscapes - A systematic review

The development of biodiversity-friendly agricultural landscapes is of major importance to meet the sustainable development challenges of our time. The emergence of unmanned aerial vehicles (UAVs), i.e. drones, has opened a new set of research and management opportunities to achieve this goal. On the one hand, this review summarizes UAV applications in agricultural landscapes, focusing on biodiversity conservation and agricultural land monitoring, based on a systematic review of the literature that resulted in 550 studies. Additionally, the review proposes how to integrate UAV research in these fields and point to new potential applications that may contribute to biodiversity-friendly agricultural landscapes. UAV-based imagery can be used to identify and monitor plants, floral resources and animals, facilitating the detection of quality habitats with high prediction power. Through vegetation indices derived from their sensors, UAVs can estimate biomass, monitor crop plant health and stress, detect pest or pathogen infestations, monitor soil fertility and target patches of high weed or invasive plant pressure, allowing precise management practices and reduced agrochemical input. Thereby, UAVs are helping to design biodiversity-friendly agricultural landscapes and to mitigate yield-biodiversity trade-offs. In conclusion, UAV applications have become a major means of biodiversity conservation and biodiversity-friendly management in agriculture, while latest developments, such as the miniaturization and decreasing costs of hyperspectral sensors, promise many new applications for the future.

Common bean resistance to Xanthomonas is associated with upregulation of the salicylic acid pathway and downregulation of photosynthesis

Background

Common bacterial blight (CBB) caused by Xanthomonas phaseoli pv. phaseoli and Xanthomonas citri pv. fuscans is one of the major threats to common bean crops (Phaseolus vulgaris L.). Resistance to CBB is particularly complex as 26 quantitative resistance loci to CBB have been described so far. To date, transcriptomic studies after CBB infection have been very scarce and the molecular mechanisms underlying susceptibility or resistance are largely unknown.

Results

We sequenced and annotated the genomes of two common bean genotypes being either resistant (BAT93) or susceptible (JaloEEP558) to CBB. Reciprocal BLASTp analysis led to a list of 20,787 homologs between these genotypes and the common bean reference genome (G19833), which provides a solid dataset for further comparative analyses. RNA-Seq after inoculation with X. phaseoli pv. phaseoli showed that the susceptible genotype initiated a more intense and diverse biological response than the resistant genotype. Resistance was linked to upregulation of the salicylic acid pathway and downregulation of photosynthesis and sugar metabolism, while susceptibility was linked to downregulation of resistance genes and upregulation of the ethylene pathway and of genes involved in cell wall modification.

Conclusions

This study helps better understanding the mechanisms occurring during the early colonization phase of common bean by Xanthomonas and unveils new actors potentially important for resistance and susceptibility to CBB. We discuss the potential link between the pathways induced during bean colonization and genes induced by transcription activator-like effectors (TALEs), as illustrated in other Xanthomonas pathovars.

Interactive effects of fish predation and sublethal insecticide concentrations on freshwater zooplankton communities

Stresses imposed by insecticides and predators are possibly the most rigorous filters to which aquatic organisms are exposed in rivers and lakes associated with agricultural lands. However, their interactive effects on zooplankton communities are still unclear. This study elucidated the zooplankton community response to fish predation, the insecticide chlorpyrifos (CLP), and a combination of both factors, using a 30-day mesocosm experiment. The zooplankton assemblage was influenced by fish presence prior to CLP toxicity. Fish predation reduced microcrustacean density leading to a community dominated by microzooplankton (i.e.: rotifers and copepod nauplii). CLP decreased the species richness in treatments with and without fish, yielding an increase in the abundance of bdelloid rotifers, in the genera Lepadella and Trichocerca. The zooplankton:phytoplankton (<20 μm) ratio decreased substantially when the two stressors, fish predation and insecticide toxicity, were combined. Although CLP dissipated relatively rapidly in the aqueous phase and accumulated in sediment and fish tissue, zooplankton richness was unable to recover. A possible explanation for this could be the inhibitory effect of CLP on resting stage hatchings in the sediment. Therefore, the combined effects of fish predation and CLP might influence zooplankton richness, leading to an assemblage dominated by rotifers that appeared to be resistant to both factors, with a limited capability to control phytoplankton growth. Thus, the effects of natural and anthropogenic stressors should be considered together when assessing community dynamics in aquatic ecosystems.

Time-Dependent Effects of Bentazon Application on the Key Antioxidant Enzymes of Soybean and Common Ragweed

The presence or absence of light is one of the most significant environmental factors affecting plant growth and defence. Therefore, the selection of the most appropriate time of application may maximize the benefits of photosynthetic inhibitors. In this work, the concentration and daytime or night-time-dependent effects of bentazon were tested in soybean and common ragweed. The recommended dose (1440 g ha−1) and also half the recommended dose significantly reduced the maximum quantum yield (Fv/Fm) and increased H2O2 levels in common ragweed. Interestingly, bentazon did not change Fv/Fm in soybean. The activity of superoxide dismutase changed in a dose-dependent manner only in common ragweed. The activity of ascorbate peroxidase, catalase and glutathione S-transferase (GST), as well as the contents of ascorbate (AsA) and glutathione (GSH) did not change significantly in this plant species. In soybean, alterations in H2O2 levels were lower but GST and APX activity, as well as AsA and GSH levels were higher compared to common ragweed. At the same time, the rate of lipid peroxidation and ion leakage increased upon bentazon, and were higher in the light phase-treated leaves in the case of both plant species. These results can contribute to optimizing the effects and uses of herbicides in agriculture.

Inter- and intraspecific variation of spider mite susceptibility to fungal infections: Implications for the long-term success of biological control

Spider mites are severe pests of several annual and perennial crops worldwide, often causing important economic damages. As rapid evolution of pesticide resistance in this group hampers the efficiency of chemical control, alternative control strategies, such as the use of entomopathogenic fungi, are being developed. However, while several studies have focused on the evaluation of the control potential of different fungal species and/or isolates as well as their compatibility with other control methods (e.g., predators or chemical pesticides), knowledge on the extent of inter- and intraspecific variation in spider mite susceptibility to fungal infection is as yet incipient. Here, we measured the mortality induced by two generalist fungi, Beauveria bassiana and Metarhizium brunneum, in 12 spider mite populations belonging to different Tetranychus species: T. evansi, T. ludeni, and T. urticae (green and red form), within a full factorial experiment. We found that spider mite species differed in their susceptibility to infection by both fungal species. Moreover, we also found important intraspecific variation for this trait. These results draw caution on the development of single strains as biocontrol agents. Indeed, the high level of intraspecific variation suggests that (a) the one-size-fits-all strategy may fail to control spider mite populations and (b) hosts resistance to infection may evolve at a rapid pace. Finally, we propose future directions to better understand this system and improve the long-term success of spider mite control strategies based on entomopathogenic fungi.

Pesticide use, production risk and shocks. The case of rice producers in Vietnam

In this paper, we try to understand pesticide input decisions among Vietnamese rice producers by examining the production risk effects of pesticide use, applying both a lottery game and a more traditional production function approach. Production function estimates show that excessive pesticide use makes production riskier. This result is supported by the lottery approach, which signals that more risk averse farmers use less pesticide, implying that pesticide is a risk-increasing input. We also show, that higher uncertainty regarding drought relative to pest is likely driving the increasing risk effect of pesticides. Therefore, we claim that the relative importance of multiple uncertainties on pest and water is relevant to determine the risk property of pesticide.