Copper-based Fungicides Research Articles

Efficacy of using grape cane extracts against <i>Plasmopara viticola</i> under field conditions and their impact on the composition of berries and musts of <i>Vitis vinifera</i> L. cv. Riesling

Grapevine downy mildew caused by Plasmopara viticola is a deleterious vine disease currently controlled using synthetic and copper-based fungicides. Environmental concerns surrounding such fungicides necessitate sustainable alternatives like grape cane extracts. However, studies into their efficacy and effects on the product remain limited. This study aimed to assess the open-field efficacy of a novel grape cane extract formulation, alone and combined with a copper agent, against downy mildew, and to examine its impact on berry and must composition. The results were compared to standard fungicides frequently used in integrated and organic viticulture. In 2022, the grape cane extract formulation reduced downy mildew severity by 78 % on berry clusters, comparable to the maximum acceptable dose of copper for organic farming in Germany (3 kg/ha/a). Combining the grape cane extract with the copper agent was more effective than the copper agent alone, but not more effective than the grape cane extract alone. In 2023, disease development was marginal, despite artificial inoculation. Compositional differences detectable by FTIR were insignificant between musts derived from all treatments, increased copper levels were observed whenever copper had been applied. The phenolic content in freeze-dried, de-seeded berries of 2022 was significantly lower after copper (14.6 mg/g dry weight DW) and grape cane extract treatments (6.6 mg/g DW) when compared to the control (36.1 mg/g DW), with discrepancies in stilbenoid and flavan-3-ol levels in particular, as analysed by HPLC-DAD. However, these differences were not confirmed in 2023, with results showing no correlations between different treatments and phenolic contents. These findings suggest that applications of the phenolic grape cane extract do not lead to artificially altered levels or relevant residues of the active constituents; i.e., the phenolic compounds in the product. In brief, grape cane extracts might represent a promising natural alternative to controlling grapevine downy mildew, particularly in organic viticulture, which, to date, heavily relies on (eco-)toxic copper-pesticides. Further multi-year studies including wine analyses are warranted to follow the entire flow towards the final product.

Pest management facing warming and chemical stresses: Multi-stress effects on the biological agent Trichogramma oleae

Global change is affecting plant-insect interactions in agroecosystems and can have dramatic consequences on yields when causing non-targeted pest outbreaks and threatening the use of pest natural enemies for biocontrol. The vineyard agroecosystem is an interesting system to study multi-stress conditions: on the one hand, agricultural intensification comes with high inputs of copper-based fungicides and, on the other hand, temperatures are rising due to climate change. We investigated interactive and bottom-up effects of both temperature increase and copper-based fungicides exposure on the important Lepidopteran vineyard pest Lobesia botrana and its natural enemy, the oophagous parasitoid Trichogramma oleae. We exposed L. botrana larvae to three increasing copper sulfate concentrations under two fluctuating thermal regimes, one current and one future. Eggs produced by L. botrana were then exposed to T. oleae. Our results showed that the survival of L. botrana, was only reduced by the highest copper sulfate concentration and improved under the warmer regime. The development time of L. botrana was strongly reduced by the warmer regime but increased with increasing copper sulfate concentrations, whereas pupal mass was reduced by both thermal regime and copper sulfate. T. oleae F1 emergence rate was reduced and their development time increased by combined effects of the warmer regime and increasing copper sulfate concentrations. Size, longevity and fecundity of T. oleae F1 decreased with high copper sulfate concentrations. These effects on the moth pest and its natural enemy are probably the result of trade-offs between the survival and the development of L. botrana facing multi-stress conditions and implicate potential consequences for future biological pest control. Our study supplies valuable data on how the interaction between pests and biological control agents is affected by multi-stress conditions.

Adverse effects of the Bordeaux mixture copper-based fungicide on the non-target vineyard pest Lobesia botrana.

Bordeaux mixture is a copper-based fungicide commonly used in vineyards to prevent fungal and bacterial infections in grapevines. However, this fungicide may adversely affect the entomological component, including insect pests. Understanding the impacts of Bordeaux mixture on the vineyard pest Lobesia botrana is an increasing concern in the viticultural production. Bordeaux mixture had detrimental effects on the development and reproductive performance of L. botrana. Several physiological traits were adversely affected by copper-based fungicide exposure, including a decrease in larval survival and a delayed larval development to moth emergence, as well as a reduced reproductive performance through a decrease in female fecundity and fertility and male sperm quality. However, we did not detect any effect of Bordeaux mixture on the measured reproductive behaviors (mating success, pre-mating latency and mating duration). Ingestion by larvae of food contaminated with Bordeaux mixture had a negative effect on the reproductive performance of the pest L. botrana, which could affect its population dynamics in vineyards. Although this study highlighted collateral damage of Bordeaux mixture on L. botrana, the potential impact of copper-based fungicides on vineyard diversity, including natural predators is discussed and needs to be taken in consideration in integrated pest management. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Anti-black pod disease activity of leaf extract of Carica papaya Linn

BackgroundTheobroma cacao (Cocoa) is a major foreign exchange earner for Ghana. Over the recent decades, there has been a consistent decline in cocoa production in the country. A major contributing factor is the cocoa black pod disease caused by Phytophthora species. Synthetic fungicides have been used to control the pathogens over the years. However, recent calls for organic cocoa devoid of residues from synthetic fungicides, which are known to pose several health challenges as well as a negative impact on the environment, have gained attention. Thus, inviting investigations into more environmentally friendly and sustainable alternatives to synthetic fungicides. ObjectiveThis study explored the inhibitory potential of crude extract from Carica papaya against cocoa black pod disease caused by Phytophthora spp. Material and methodsAn in-silico study was done using known phytochemicals from Carica papaya as ligands against a Phytophthora effector protein. Crude extracts were obtained from the plant materials using 70 % ethanol as the extraction solvent. The crude Green Leaf Extract (GLE), Aging Induced Chlorophyll Deficient Leaf Extract (AICDLE), and Matured Black Seed Extract (SDE) were tested in-vitro against pre-cultured P. palmivora and P. megakarya using the poison food technique. GLE was modulated with Delco, a synthetic fungicide, at different ratios which were tested in-vitro and in-vivo. ResultsA total of 16 ligands showed binding affinity higher or equal to the standard ligand, alliin, suggesting Carica papaya as a repository of anti-phytophthora agents. Assessment of crude extracts at concentrations 5–20 mg/ml showed fungistatic activity against P. palmivora and P. megakarya in-vitro. Modulation of GLE with Delco produced some combinations that made GLE fungicidal in-vitro against P. palmivora and P. megakarya with fractional inhibition concentration indices between 0.51 and 0.65, interpreted as partially synergistic. The in-vivo assessment of combination D (Delco and GLE in a 0.3 mg:3 mg per ml ratio) performed as well as Delco alone at the recommended dose of 5 mg/ml. Thus, combination D reduces the requirement for copper-based fungicide by over 90 %. ConclusionThis study shows Carica papaya in a new light as a potential material that could be formulated into a natural product-based fungicide for combating Phytophthora-induced black pod disease.

Biological effects of a copper-based fungicide on the fruit fly, Drosophila melanogaster

The increased consumption of pesticides can have a negative environmental impact by increasing the essential metals to toxic levels. Bordasul® is a commonly used fungicide in Brazil and it is composed of 20% Cu, 10% sulfur, and 3.0% calcium. The study of fungicides in vivo in non-target model organisms can predict their environmental impact more broadly. The Drosophila melanogaster is a unique model due to its ease of handling and maintenance. Here, the potential toxicity of Bordasul® was investigated by assessing the development, survival, and behavior of exposed flies. Exposure to Bordasul® impaired the development (p < 0.01) and caused a significant reduction in memory retention (p < 0.05) and locomotor ability (p < 0.001). Fungicides are needed to assure the world’s food demand; however, Bordasul® was highly toxic to D. melanogaster. Therefore, Bordasul® may be potentially toxic to non-target invertebrates and new environmentally-safe biofertilizers have to be developed to preserve the biota.

Three-dimensional dendritic biosynthetic copper oxide nanoparticles: A novel approach for enhanced leaf deposition and retention to reduce environmental impact

Copper-based fungicides are commonly utilized as protective germicides; however, their susceptibility to rain-induced washing leads to a substantial copper exposure, resulting in significant environmental pollution and potential ecological risks. This study focuses on the biosynthesis of copper oxide nanoparticles at room temperature, utilizing copper sulfate pentahydrate and tea seed cake extract as reactive raw materials. The obtained copper oxide nanoparticles exhibit a distinctive dendritic three-dimensional topology. Notably, these copper oxide nanoparticles demonstrate superior wettability and spreadability on tomato, rice, and wheat leaves compared to the commercial formulation of copper hydroxide (Kocide). The retention amount of copper oxide nanoparticles on the surface of plant leaves after rain washing exhibited a 75.89% to 84.31% increase compared to that of Kocide, attributed to the structural chimerism of copper oxide nanoparticles and the micro-nano structure of leaves. Regarding antimicrobial activity against Magnaporthe oryzae and Clavibacter michiganense, copper oxide nanoparticles showed better residual activity and a longer persistent period than Kocide. Safety experiments demonstrated that copper oxide nanoparticles had minimal adverse effects on wheat plants, while in vivo studies in zebrafish revealed their effectiveness in reducing toxicity by over five-fold compared to Kocide. Furthermore, soil ecosystem assessments highlighted the high biocompatibility of copper oxide nanoparticles with Escherichia coli. Consequently, the prepared copper oxide nanoparticles hold significant promise as an eco-friendly alternative to traditional copper-based fungicides.

The effect of copper reduction on the control of downy mildew in Mediterranean grapevines

The application of copper-based fungicides has led to the problematic accumulation of copper in the soil of many European vineyards. In this work, we tested the effectiveness of downy mildew control strategies that considerably reduce the amount of copper, through the application of other non-toxic compounds. The study took place in three different regions of Catalonia, by combining smaller and larger-scale trials for two growing seasons. Although variations among experiments were detected, the treatments used here may reduce the applied copper content by up to 77 percent. The cooper reduction-strategies, which alternated standard copper application of copper oxychloride with applications of products based on Equisetum arvense L., or with applications of products with heptagluconic acid (an alternative formulation with a very low-rate of copper), provided the most consistent protection against downy mildew. Moreover, these treatments reduced copper inputs by 63 and 47 percent as compared to conventional treatments based on repeated applications of copper oxychloride. This work underlines the possibility of reducing the amount of copper applied to control downy mildew in Mediterranean vineyards, through the use of newly-developed formulations.

Heavy metal status in cocoa (Theobroma cacao L.) soils and beans: the case of Abuakwa North Municipality of Eastern Region, Ghana.

In recent times, public concerns over the potential accumulation of heavy metals in agricultural soils and crops due to the excessive use of agrochemicals are increasing. This study was conducted in the Abuakwa North Municipality of Eastern Region, Ghana, to assess the status of heavy metals in cocoa soils and beans. Cocoa farms aged between 10 and 20years and have received agrochemicals for at least 5years were selected, and their adjacent forests were used as controls. Soil samples and cocoa pods were collected randomly and processed for laboratory analysis. The study discovered that across the sampling sites, heavy metal concentrations in soil were below permissible limits. However, contamination factor and geo-accumulation index results revealed that Tontro cocoa farms were considerably contaminated and moderately polluted respectively with Cu, probably due to long-term fungicide application. The concentrations of Fe (39.3-47.1mgkg-1) and Zn (54.8-70.0mgkg-1) in the cocoa beans across the communities were below the FAO/WHO's safe limit of 99.4mgkg-1 and 73.0mgkg-1 respectively. Lead (0.03-0.06mgkg-1) and Cd (0.12-0.20mgkg-1) concentrations were below the EU's maximum allowable level and Codex Alimentarius Commission's limit of 1.0mgkg-1 respectively. However, bean Cu content in the Tontro farm (51.5mgkg-1) was slightly above the EU's recommended maximum limit of 50.0mgkg-1, possibly due to the continuous application of copper-based fungicides. The study showed that, overall, agrochemicals used for cocoa farming in Abuakwa North Municipality of Ghana did not cause serious harm to the soils and beans, since the mean metal concentrations were not alarming and guarantee public health safety.

Newly Isolated Trichoderma spp. Show Multifaceted Biocontrol Strategies to Inhibit Potato Late Blight Causal Agent Phytophthora infestans both In Vitro and In Planta

Potato growers worldwide have been at war for more than 150 years with an enemy whose lifecycle, genome size and architecture, infection rate, and economic impacts are the epitome of a plant pathogen. Phytophthora infestans is an oomycete that causes the notorious late blight infection in potato and tomato fields. This study explored the benefits of the multitalented plant symbiotic fungi Trichoderma spp. and their metabolites as potential biopesticides against P. infestans. Eleven strains of Trichoderma spp. were obtained from soil and tree barks and were identified using DNA sequence analysis of three molecular markers. The antagonistic potential of the strains against P. infestans was first evaluated in vitro. In dual-culture assays, P. infestans growth was significantly inhibited (53 to 95%) by different Trichoderma spp. through direct mycoparasitism, competition for space and nutrients, or antibiosis. The cell-free filtrates (CFFs) of different Trichoderma strains were obtained and characterized for anti- Phytophthora activities as well as biochemical stability. The obtained results indicated that Trichoderma CFFs were chemically stable and strongly decreased P. infestans’ mycelial growth and zoospore motility and viability. Similarly, in leaf-disk assays, Trichoderma CFFs showed significant protection against P. infestans infection. Ultraperformance liquid chromatography analysis revealed the presence of harzianic acid, iso-harzianic acid, and 6-pentyl-2H-pyran-2-one as major compounds in different Trichoderma CFFs. Furthermore, selected Trichoderma strains significantly protected potato plants against soil-mediated late blight infection. Finally, Trichoderma spp. showed high compatibility with a copper-based fungicide, especially at lower concentrations, suggesting that both protective agents could be combined in integrated pest management programs. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Sulfur — a potential additive to increase the efficacy of copper-based fungicides against grapevine downy mildew

Control of downy mildew on grapevines in organic viticulture in Europe is mainly based on using copper-based fungicides. However, the effect of these agents is often insufficient to prevent losses when infestation pressure is high. The addition of sulfur, which is primarily used to control powdery mildew, improves the effect of copper on downy mildew. In three out of five trial years, sulfur had a clear positive effect when it was added during spray treatments against Plasmopara viticola, the causal agent of downy mildew on grapevines. This was evident mainly in the fruits; no further positive effect on the leaves was evident. In addition, the present study shows that copper-based fungicides are effective on leaves but have a rather poor effect on grapevine fruit. Furthermore, the study demonstrates that the effect of copper is significantly worse than that of the chemical synthetic contact fungicide folpet.

Suppression of Hop Downy Mildew as Influenced by the Timing of Selected Fungicides

Downy mildew of hop is a disease that is controlled by the implementation of cultural practices along with the application of fungicides, as there are few cultivars with high levels of resistance to this disease. We conducted studies in western Oregon to elucidate the effect of using synthetic fungicides of various modes of action early versus late in disease management programs when rotated with a copper-based fungicide. When analyzed over the 4 years of this study, there were independent effects from both the specific fungicide mode of action and application timing on disease control. The use of cymoxanil + copper hydroxide or mandipropamid in a program reduced the area under the disease progress curve by 66.3 or 59.7 units (17.7 or 19.6%), respectively, as compared with phosphorous acid. Using synthetic fungicides in the first two applications in a program provided better disease control than using the same fungicides in the third and fourth applications, reducing the area under the disease progress curve by 47.8 units (14.4%). By simply applying modes of action found to be more efficacious earlier in the growing season, the severity of downy mildew was reduced as much as 32% without increasing the total number of applications made.

Remediate and sense: alginate beads empowered by portable electrochemical strips for copper ion removal and detection at environmental sites.

The contamination of environmental sites due to the presence of persistent species represents an important issue to be tackled. In particular, the presence of high levels of metals in soil and surface water is more frequent. One of the metals that sometimes exceeds the permissible limit set by regulatory authorities is copper. For instance, copper-based fungicides are widely used in viticulture. However, copper ions remain in soil and can enter the food chain, posing threats to human health and environmental safety. Although the rapid detection of copper ions using portable sensors is effective in enhancing early warning, it sometimes solves only half of the problem as remediation is not considered. In this paper, we present a novel integrated/portable approach that merges the remediation and sensing of metals by proposing a remediate-and-sense concept. In order to realize this concept, alginate beads were coupled with printed electrochemical strips for on-site copper detection. Within the same architecture, alginate beads were used to remove copper ions from the soil, and printed electrochemical strips were used to evaluate the efficacy of remediation at the point of need. The concept was applied towards soil containing copper ions at the parts per billion level; with few alginate beads and in the absence of additional species, copper ions were quantitatively removed from the matrix; and 3D printing allowed us to combine the printed strips and spheres within a unique tool. The architecture was optimized and the results were compared to inductively coupled plasma-mass spectrometry (ICP-MS) measurements with a recovery percentage of 90%-110%. It should be noted that this novel portable approach may be applied to other pollutants, opening new possibilities for integrated remediation and sensing.

Effect of copper-based fungicide on chemical composition of cocoa seeds

Effect of copper-based fungicide on chemical composition of cocoa seeds

The integrated disease management of early blight in organically grown tomato under hill condition of Sikkim, India

Tomato (Lycopersicon esculentum Mill.) is the most widely cultivated vegetable crop in the world and early blight caused by Alternaria spp. is one of the major production constraints. Survey was conducted during kharif seasons of 2018-19 &amp;2019-20 in four districts of Sikkim. Maximum early blight disease severity was recorded in south district of Sikkim. Pathogenicity test of isolates collected from different location were established. Morphological, cultural, and molecular identification of the pathogen reveal pathogen as Alternaria spp. Five different bio-control agents i.e., Trichoderma harzianum, T. Viride, Pseudomonas fluorescens, Bacillus subtilis and Bacillus cereus were evaluated against the test pathogens. Among the bio-control agents tested, Trichoderma harzianum (74.89%) and Trichoderma viride (69.41%) showed maximum percent growth inhibition. Open field experiment was conducted with eleven treatments formulated by integrating the different organic inputs, biocontrol agents and copper-based fungicide as chemical check. Organic treatment T9 {Susceptible Variety + Soil treatment with Trichoderma harzianum @1:25(1kg Trichoderma + 25 Kg of FYM) + cow dung slurry 10% + Nimbicidine 0.3% + Panchagavya 10% + Cow Urine 10%} consistently showed the best result among the bioresources tested. Keywords: Tomato, Organic, Bio agent and Integrated disease management

Co-Composting of Hop Bines and Wood-Based Biochar: Effects on Composting and Plant Growth in Copper-Contaminated Soils

Decades of intensive use of copper-based fungicides against downy mildew in hops has led to considerable accumulation of copper in topsoil, resulting in toxic effects on plants. Due to its high sorption capacity, the application of co-composted biochar compost might reduce copper toxicity, whereby a synergistic effect of the composting process is supposed to occur. Furthermore, biochar addition might improve the composting process itself. Therefore, hop bines were co-composted without as well as with 5 and 20 vol% biochar, respectively. During composting, the temperature and concentration of O2, CO2, H2S, CH4 and NH3 in the compost heaps were regularly recorded. The biochar-free compost as well as the two composts with the biochar addition were characterized with regard to their plant-growing properties and were mixed into soils artificially spiked with different amounts of copper as well as into copper-polluted hop garden and apple orchard soils. The respective soil without the compost addition was used as the control, and further treatments with biochar alone and in combination with biochar-free compost were included in a plant response test with Chinese cabbage. The biochar addition increased the temperature within the compost heaps by about 30 °C and extended the duration of the thermophilic phase by almost 30 days, resulting in a higher degree of hygienization. Furthermore, the application of co-composted biochar composts significantly improved plant biomass by up to 148% and reduced the copper concentration, especially of roots, by up to 35%. However, no significant differences in the biochar-free compost were found in the artificially copper-spiked soils, and the effect of co-composted biochar compost did not differ from the effect of biochar alone and in combination with biochar-free compost. Nevertheless, the co-composting of hop bines with biochar is recommended to benefit from the positive side effect of improved sanitization in addition to reducing copper toxicity.

Prevalence and spatial distribution of cranberry fruit rot pathogens in British Columbia, Canada and potential fungicides for fruit rot management.

Twenty-eight cranberry farms in southwestern British Columbia were investigated for the prevalence and spatial distribution of fungal pathogens that contribute to fruit rot incidence. Farms were selected from six regions where most cranberry production is concentrated. Flowers, and green and ripe fruit (var. 'Stevens') samples, collected during two consecutive crop seasons, were analyzed for fruitrot pathogens. The most frequently isolated pathogens were identified asAllantophomopsis cytisporea, Botrytis cinerea, Coleophoma empetri, Colletotrichum fioriniae, Colletotrichum gloeosporioides, Fusicoccum putrefaciens, Glomerella sp., Phomopsis vaccinii, Phyllosticta elongata, Phyllosticta vaccinii and Physalospora vaccinii. The pathogens Allantophomopsis cytisporea, Phyllosticta spp., and Physalospora vaccinii were found at high incidence. These pathogens were present in all cranberry growing regions, although their mean percentage incidence varied from farm-to-farm and region-to-region. Amongst the pathogens from three phenological stages of cranberry crop examined, ripe fruit had the highest percentage incidence of fruit rot pathogens compared to that of flowers or green fruit; thus, indicating their presence at the early stages of crop development. The efficacy to inhibit the mycelial growth and spore germination of the fruit rot pathogens by twenty six fungicides, belonging to nine different modes of actions, were evaluated in vitro. The copper-based fungicides and captan of group M, flutriafol, triforine, difenoconazole, prothioconazole and propiconazole of group 3, benzovindiflupyr of group 7, and fosetyl-Al of group 33 demonstrated a high degree of efficacy in inhibiting the mycelial growth of all fruit rot pathogens. The fungicides chlorothalonil of group M, fenbuconazole of group 3, pyrimethanil and cyprodinil of group 9, and fludioxonil of group 12 also demonstrated activity against most fruit rot pathogens. The copper-based fungicides, chlorothalonil, captan, flutriafol, triforine, difenoconazole, prothioconazole, propiconazole, benzovindiflupyr, and fosetyl-Al effectively prevented the spore germination of most fruit rot pathogens. This demonstrated activity of the fungicides towards cranberry fruit rot pathogens should be assessed for efficacy in planta under field conditions. The current study identified the most critical fungal pathogens causing fruit rot of cranberry in British Columbia and potential fungicides that could be used in the management of fruit rot and to improve fruit quality and yield.

Managing insect and plant pathogen pests with organic and conventional pesticides in onions.

Onion thrips (Thrips tabaci Lindeman, Thysanoptera: Thripidae) is a significant insect pest of onions (Allium cepa L., Asparagales: Amaryllidaceae). In addition to feeding on onion foliage, they may spread plant pathogens. Currently, onion thrips and pathogens are managed as separate pests with insecticides and fungicides. It may be beneficial to manage these pests simultaneously as limiting onion thrips may reduce pathogen damage. We tested combinations of bio- and conventional pesticides in a season-long management program in Michigan onion fields. From 2020 to 2022, we counted onion thrips weekly and visually estimated plant foliage necrotic damage (%) in experimental plots each year. In 2020, we tested 6 treatment programs including: azadirachtin, spinosad, a copper-based fungicide, azadirachtin + copper-based fungicide, spinosad + copper-based fungicide, and untreated control. The thrips populations were not significantly reduced compared to the control, but necrotic damage was reduced significantly in spinosad-treated plots. In 2021, we tested a combination of 8 bio- and conventional pesticide programs. Compared to the control, the bioinsecticides did not reduce onion thrips populations, but the conventional pesticide programs reduced both onion thrips numbers and necrotic damage. In 2022, we tested only conventional insecticide programs but included 3 different action thresholds for initiation and applied them with or without a fungicide, for 8 treatments. All insecticide programs reduced onion thrips compared to the control, the action threshold did not impact thrips numbers significantly. Overall, the use of action thresholds can lead to fewer insecticide applications and a lower incidence of leaf damage.

Biopesticides as alternatives to reduce the use of copper in Spanish and Portuguese viticulture: Main trends in adoption

The traditional use of copper as a fungicide in vineyards has raised concerns among authorities as it increases environmental pollution. As a result, new regulations have been enacted to reduce the use of plant protection products while encouraging the use of biological pesticides, which are less harmful to the environment. In this study, we surveyed two of the most relevant countries in terms of vine cultivation: Spain and Portugal. The objective of this study was to analyse the factors influencing the use of copper-based fungicides and their biological alternatives to provide a framework for state-of-the-art downy mildew control. This has led to some forward-thinking on the applicability of EU objectives. A probabilistic LogiT model was used to observe the field and exploitation variables that influenced winegrowers’ use of biopesticides. Given its great reliance on copper, it can be concluded that copper is still a necessary product for viticulture. Moreover, because the use of synthetic products is prohibited in organic vineyards, more copper treatments are carried out. Although the intention to use biopesticides exists, this did not result in actual use. The most influential factor in the probability of biopesticide use is knowledge of the legislation; however, it is also important to have watercourses near the field and to have the necessary technology. These results are relevant for formulating recommendations to ensure that all information reaches small farmers, as this would be key to more sustainable agriculture in Europe.

Toxic Effects of Copper Fungicides on the Development and Behavior of Zebrafish in Early-Life Stages.

Copper-based fungicides have been used to control various plant diseases for more than one hundred years and play very important roles in agriculture. Accumulation of copper in freshwater and environment pose severe threats to human health and the environment. The current study evaluated the developmental and behavioral toxicity of PEG@Cu NCs (copper nanoclusters), Kocide® 3000 (copper hydroxide), and Cu(CH3COO)2 (copper acetate) to zebrafish in early-life stages. The developmental toxicity was evaluated according to the parameters of mortality, hatching rate, autonomous movement and heartbeat of embryos, and body length of larvae. The 9 dpf (days postfertilization)-LC50 (50% lethal concentration) of embryonic mortality was 0.077, 0.174 or 0.088 mg/L, and the 9 dpf-EC50 (effective concentration of 50% embryos hatching) of hatching rate was 0.079 mg/L, 0.21 mg/L and 0.092 mg/L when the embryos were exposed to PEG@Cu NCs, Kocide® 3000 or Cu(CH3COO)2, respectively. Kocide® 3000 and Cu(CH3COO)2 obviously decreased the spontaneous movements, while PEG@Cu NCs had no adverse effects on that of embryos. The reduced heartbeat can return to normal after exposure to PEG@Cu NCs for 96 h, while it cannot recover from Kocide® 3000. In addition, Kocide® 3000 (≥0.2 mg/L), PEG@Cu NCs and Cu(CH3COO)2 with 0.05 mg/L or higher concentration exhibited obvious behavioral toxicity to zebrafish larvae according to the parameters of movement distance, average velocity, absolute sinuosity, absolute turn angle and absolute angular velocity.

Unravelling molecular mechanisms involved in resistance priming against downy mildew (Plasmopara viticola) in grapevine (Vitis vinifera L.)

Downy mildew (DM; Plasmopara viticola) is amongst the most severe fungal diseases in viticulture and the reason for the majority of fungicide applications. To reduce synthetic and copper-based fungicides, there is an urgent need for natural alternatives, which are being increasingly tested by the industry and the research community. However, their mode of action remains unclear. Therefore, our study aimed to investigate the transcriptomic changes induced by oregano essential oil vapour (OEOV) in DM-infected grapevines. OEOV was applied at different time points before and after DM infection to differentiate between a priming effect and a direct effect. Both pre-DM treatment with OEOV and post-infection treatment resulted in a significant reduction in DM sporulation. RNA-seq, followed by differential gene expression and weighted gene co-expression network analysis, identified co-expressed gene modules associated with secondary metabolism, pathogen recognition and response. Surprisingly, the molecular mechanisms underlying the efficiency of OEOV against DM appear to be independent of stilbene synthesis, and instead involve genes from a putative signalling pathway that has yet to be characterized. This study enhances our understanding of the molecular regulation of innate plant immunity and provides new insights into the mode of action of alternative natural antifungal agents.