Botanical and chemical fungicides in the treatment of commercial seeds of Brachiaria brizantha and Panicum maximum.

Brazil is the largest producer, consumer, and exporter of forage seeds in the world. However, the high incidence of pathogens threatens the seed production system, resulting in decreases in production and quality. Currently, the emphasis has been placed on the use of alternative products as a way of maintaining productivity and environmental sustainability. Thus, the objective of this study was to evaluate the mycoflora associated with the commercial seeds of Brachiaria brizantha and Panicum maximum treated with chemical and alternative fungicide. To test with chemical and alternative treatments, seeds were subjected to fluazinam + thiophanate-methyl, fludioxonil + metalaxyl-M, noni essential oil, rosemary pepper essential oil, sulfuric acid. There was also an untreated control. The most efficient products in the control of incident fungi were, in decreasing order, fluazinam + thiophanate-methyl, fludioxonil + metalaxyl-M, noni essential oil, rosemary pepper essential oil, and sulfuric acid. Fungicides mainly controlled the genera Alternaria, Aspergillus, Bipolaris, Chaetomium, Cladosporium, Colletotrichum, Curvularia, Fusarium, Penicillium, Phoma and Rhizopus. Essential oils showed positive effects in controlling Bipolaris, Curvularia, and Fusarium. Sulfuric acid reduced the incidence of Bipolaris, Colletotrichum, Curvularia, Fusarium, Phoma, and Rhizopus. Seed treatment is one of the promising strategies for obtaining seeds of a healthy quality. As a result, the fungicides and botanical components listed above were promising in reducing fungi associated with forage seeds and can be used for seed treatments and in the development of new products with a natural base through essential oils.

Natural products, their derivatives, mimics and synthetic equivalents: role in agrochemical discovery.

Natural products (NPs) have a long history as a source of, and inspiration for, novel agrochemicals. Many of the existing herbicides, fungicides, and insecticides have their origins in a wide range of NPs from a variety of sources. Owing to the changing needs of agriculture, shifts in pest spectrum, development of resistance, and evolving regulatory requirements, the need for new agrochemical tools remains as critical as ever. As such, NPs continue to be an important source of models and templates for the development of new agrochemicals, demonstrated by the fact that NP models exist for many of the pest control agents that were discovered by other means. Interestingly, there appear to be distinct differences in the success of different NP sources for different pesticide uses. Although a few microbial NPs have been important starting points in recent discoveries of some insecticidal agrochemicals, historically plant sources have contributed the most to the discovery of new insecticides. In contrast, fungi have been the most important NP sources for new fungicides. Like insecticides, plant-sourced NPs have made the largest contribution to herbicide discovery. Available data on 2014 global sales and numbers of compounds in each class of pesticides indicate that the overall impact of NPs to the discovery of herbicides has been relatively modest compared to the impact observed for fungicides and insecticides. However, as new sourcing and approaches to NP discovery evolve, the impact of NPs in all agrochemical arenas will continue to expand. © 2016 Society of Chemical Industry.

A predictive data-driven framework for endocrine prioritization: a triazole fungicide case study.

The US Environmental Protection Agency Endocrine Disruptor Screening Program (EDSP) is a tiered screening approach to determine the potential for a chemical to interact with estrogen, androgen, or thyroid hormone systems and/or perturb steroidogenesis. Use of high-throughput screening (HTS) to predict hazard and exposure is shifting the EDSP approach to (1) prioritization of chemicals for further screening; and (2) targeted use of EDSP Tier 1 assays to inform specific data needs. In this work, toxicology data for three triazole fungicides (triadimefon, propiconazole, and myclobutanil) were evaluated, including HTS results, EDSP Tier 1 screening (and other scientifically relevant information), and EPA guideline mammalian toxicology study data. The endocrine-related bioactivity predictions from HTS and information that satisfied the EDSP Tier 1 requirements were qualitatively concordant. Current limitations in the available HTS battery for thyroid and steroidogenesis pathways were mitigated by inclusion of guideline toxicology studies in this analysis. Similar margins (3-5 orders of magnitude) were observed between HTS-predicted human bioactivity and exposure values and between in vivo mammalian bioactivity and EPA chronic human exposure estimates for these products' registered uses. Combined HTS hazard and human exposure predictions suggest low priority for higher-tiered endocrine testing of these triazoles. Comparison with the mammalian toxicology database indicated that this HTS-based prioritization would have been protective for any potential in vivo effects that form the basis of current risk assessment for these chemicals. This example demonstrates an effective, human health protective roadmap for EDSP evaluation of pesticide active ingredients via prioritization using HTS and guideline toxicology information.

Agricultural Applications for Antimicrobials. A Danger to Human Health: An Official Position Statement of the Society of Infectious Diseases Pharmacists.

The use of antibiotics in agriculture, particularly in food-producing animals, is pervasive and represents the overwhelming majority of antibiotic use worldwide. The link between antibiotic use in animals and antibiotic resistance in humans is unequivocal. Transmission can occur by ingesting undercooked meats harboring resistant bacteria, by direct contact of animals by animal handlers, and by various other means. Antibiotics used in aquaculture and antifungals used in horticulture are also an evolving threat to human health. Regulations aimed at decreasing the amount of antibiotics used in food production to limit the development of antibiotic resistance have recently been implemented. However, further action is needed to minimize antibiotic use in agriculture. This article describes the extent of this current problem and serves as the official position of the Society of Infectious Diseases Pharmacists on this urgent threat to human health.

[Comparative hygienic assessment of potential risk to workers under application of fungicides of different classes].

The comparative hygienic evaluation of working conditions in various application technologies of triazole fungicides (tebuconazole, dyfenoconazole, penconazole) strobilurine fungicides (azoxystrobin, pyraclostrobin, trifloxystrobin), ethylene-bis-dytiocarbamate fungicides (metiram, mancozeb), cianopyrrole fungicide (fludioxonil), anilide fungicides (benalaxyl-M, boscalid), anilinopirymidyne fungicides (cyprodynil, valifenal, pirymetanil). Potential complex risk of possible harmful effects of the investigated compounds on workers by inhalation and percutaneous admission, as well as a comparative analysis of received values was assessed. Determination of active substances in the samples was carried out by gas-liquid and high performance liquid chromatography. In the air of the working area were found triazoles 0.005-0.01 mg/m3, ethylene-bis-dytiokarbamates--0.01-0.02 mg/m3 at fan plants processing, anilinopirymidynes--0.19 mg/m3 at backpack plants processing. Listed values do not exceed the established hygienic standards in the air of the working area. Steam plants processing had not accompanied by the arrival of investigated compounds in the air of the working area. For all the studied crops processing technologies magnitude of the potential risk of possible harmful effects of study classes fungicides influence at the complex admission does not exceed the permissible level (was less than 1). Comparative analysis of complex risks for workers allowed to distribute fungicides according this criterion in the following order: cianopyrrole < strobilurynes < triazoles < anilides < anilinopirymidynes < ethylene-bis-dytiokarbamates.

RDC-based determination of the relative configuration of the fungicidal cyclopentenone 4,6-diacetylhygrophorone A12..

The hygrophorones, a class of cyclopentenones isolated from fruiting bodies of the genus Hygrophorus (basidiomycetes), show promising antifungal activity. While the constitution of 4,6-diacetylhygrophorone A(12) (3) and the relative configuration of the stereogenic centers in the cyclopentenone ring were elucidated using standard NMR and MS techniques, the relative configuration of the exocyclic stereogenic center could not be assigned. By introducing a sample of 3 into an alignment medium and measuring anisotropic NMR parameters, namely, residual dipolar couplings, we were able to unambiguously determine the relative configuration of all three stereogenic centers in 4,6-diacetylhygrophorone A(12) simultaneously by fitting several structure proposals to the experimental data.

Predicting multiple ecotoxicological profiles in agrochemical fungicides: a multi-species chemoinformatic approach.

Agriculture is needed to deal with crop losses caused by biotic stresses like pests. The use of pesticides has played a vital role, contributing to improve crop production and harvest productivity, providing a better crop quality and supply, and consequently contributing with the improvement of the human health. An important group of these pesticides is fungicides. However, the use of these agrochemical fungicides is an important source of contamination, damaging the ecosystems. Several studies have been realized for the assessment of the toxicity in agrochemical fungicides, but the principal limitation is the use of structurally related compounds against usually one indicator species. In order to overcome this problem, we explore the quantitative structure-toxicity relationships (QSTR) in agrochemical fungicides. Here, we developed the first multi-species (ms) chemoinformatic approach for the prediction multiple ecotoxicological profiles of fungicides against 20 indicators species and their classifications in toxic or nontoxic. The ms-QSTR discriminant model was based on substructural descriptors and a heterogeneous database of compounds. The percentages of correct classification were higher than 90% for both, training and prediction series. Also, substructural alerts responsible for the toxicity/no toxicity in fungicides respect all ecotoxicological profiles, were extracted and analyzed.

Concentration-response analysis of differential gene expression in the zebrafish embryotoxicity test following flusilazole exposure.

The zebrafish embryotoxicity test (ZET) is considered a promising alternative model in predictive toxicology. Currently, morphological assessment of the embryo is the main readout for this assay. However, implementation of transcriptomics may help to detect more subtle effects, which may increase the sensitivity and predictability of the test. In this study, we tested a concentration response of flusilazole in the ZET. After exposure for 24 h postfertilization, microarray analysis revealed a number of processes to be regulated in a concentration-dependent way. We identified development related processes, retinol metabolism and transcription, as well as processes corresponding to the antifungal mechanism of action, steroid biosynthesis, and fatty acid metabolism, to be differentially regulated. Retinol metabolism and transcription were already significantly altered at concentrations that were not inducing morphological effects. Differential expression of genes related to steroid biosynthesis and fatty acid metabolism showed a concentration response similar to morphological response. An increase in concentration was also positively associated with an increase in magnitude of expression for individual genes within functional processes. Our study shows that transcriptomics analysis in the ZET is a more sensitive readout of compound-induced effects than morphological assessment. However, the interpretation of differential gene expression in terms of predicting morphological effects is not straightforward and requires further study.

Genetic toxicology of folpet and captan.

Folpet and captan are fungicides whose genotoxicity depends on their chemical reaction with thiols. Multiple mutagenicity tests have been conducted on these compounds due to their positive activity in vitro and their association with gastrointestinal tumors in mice. A review of the collective data shows that these compounds have in vitro mutagenic activity but are not genotoxic in vivo. This dichotomy is primarily due to the rapid degradation of folpet and captan in the presence of thiol-rich matrices typically found in vivo. Genotoxicity has not been found in the duodenum, the mouse tumor target tissue. It is concluded that folpet like captan presents an unlikely risk of genotoxic effects in humans.

Toxicity of fungicides to natural bacterial communities in wetland water and sediment measured using leucine incorporation and potential denitrification.

We assessed potential toxicity of fungicides to natural bacterial communities from a constructed wetland, located in southern Sweden, and compared the sensitivity of two endpoints indicating bacterial activity, leucine incorporation, and potential denitrification, in detecting toxicity. The effects of eight fungicides (benomyl, carbendazim, carboxin, captan, cycloheximide, fenpropimorph, propiconazole, and thiram), two bactericides (bronopol and chlortetracycline) as controls, and one reference compound (3,5-dichlorophenol), were tested in a water-sediment microcosm set-up. Leucine incorporation was measured in both the water and sediment column, while potential denitrification was measured for the entire microcosm. The bactericides and the reference compound gave sigmoid concentration-response curves for both endpoints in all but one case. The fungicides thiram, captan, and benomyl, and to a lesser extent fenpropimorph and propiconazole had quantifiable toxic effects on leucine incorporation, with EC(50) values ranging from 3 to 70 mg l(-1), while carbendazim, carboxin, and cycloheximide had little effect at the investigated concentrations. Only thiram and captan inhibited potential denitrification; the other fungicides showed no quantifiable effect. A greater toxic effect on leucine incorporation was recorded for bacterial communities associated with the water column, compared to the sediment column, for all tested compounds. Leucine incorporation was the more sensitive method for toxicity assessment of bacterial communities, and also allowed for a rapid and simple way of comparing exposure in the sediment and water column, making it an attractive standard method for community based toxicological assays in aquatic environments.

Toxicity of fungicides with different modes of action to Cladobotryum dendroides and Agaricus bisporus.

Isolates of Cladobotryum dendroides from Serbian mushroom farms and Agaricus bisporus F56 were tested for sensitivity to selected fungicides in vitro. Chlorothalonil was the most toxic fungicide to C. dendroides isolates (EC(50) values were below 1.68 mg L(-1)). Trifloxystrobin and kresoxim-methyl were not effective in growth inhibition of C. dendroides isolates (EC(50) values exceeded 300 mg L(-1)). Metalaxyl-M+mancozeb was the most toxic fungicide to strain F56 of A. bisporus, and iprodione the least toxic. The fungicide selectivity indexes for both C. dendroides and A. bisporus indicated that iprodione, chlorothalonil, captan and metalaxyl-M+mancozeb had satisfactory selective fungitoxicity. Iprodione had the best selectivity to both the pathogen and the host, although inferior than prochloraz manganese and carbendazim, fungicides officially recommended for mushroom cultivation in European Union (EU) countries.

Natural products that have been used commercially as crop protection agents.

Many compounds derived from living organisms have found a use in crop protection. These compounds have formed the basis of chemical synthesis programmes to derive new chemical products; they have been used to identify new biochemical modes of action that can be exploited by industry-led discovery programmes; some have been used as starting materials for semi-synthetic derivatives; and many have been used or continue to be used directly as crop protection agents. This review examines only those compounds derived from living organisms that are currently used as pesticides. Plant growth regulators and semiochemicals have been excluded from the review, as have living organisms that exert their effects by the production of biologically active secondary metabolites.

Pesticides selectivity list to beneficial arthropods in four field vegetable crops.

Selectivity of pesticides to beneficial arthropods is a key data for the implementation of IPM program. In the context of field vegetables crop, a set of 16 fungicides, 17 herbicides and 14 insecticides commonly used in Belgium were tested on 5 indicator species: the parasitic hymenoptera Aphidius rhopalosiphi (De Stefani-Perez) (Hym., Aphidiidae), the aphid foliage dwelling predators Adalia bipunctata (L.) (Col., Coccinellidae) and Episyrphus balteatus (Dipt., Syrphidae) and the ground-dwelling predators Aleochara bilineata (Col., Staphyllinidae) and Bembidion lampros (Col., Carabidae). Pesticides were tested according a testing scheme including a first assessment on inert substrate (glass plates for adults of A. rhopalosiphi, larvae of A. bipunctata and E. balteatus, sand on adults of A. bilineata and B. lampros) and, for product that were toxic, a second assessment on natural substrate (barley seedlings for A. rhopalosiphi, french bean plants for A. bipunctato and E. balteatus and two type of soil for 8. lampros and A. bilineato). The effects of the product were assessed on basis on mortality, except for A. bilineata (Onion fly pupae parasitism). According to the final results obtained at the end of this testing scheme, the product were listed in toxicity class: green list if effect < or =30%, yellow list 30% < effect < 60% and orange list 60% < effect < or =80%. Products with toxicity higher than 80% on plants or on soils, or that reduce parasitism more than 80% on soil were put in red list and are not recommended for IPM. Results showed that all fungicides and herbicides were included in the green list except tebuconazole and boscalid + pyraclostrobin that were labeled as yellow for A. bipunctata. In opposite, no foliar insecticide was totally selective for all beneficial tested. However some products are in green list for one or several species. Soil insecticides were all are very toxic for ground dwelling arthropods and classed in red list. All results obtained during this study and further upgrade will be available on www.cra.wallonie.be/selectivite. In conclusions, fungicides and herbicides tested are compatible with IPM programs. For foliar insecticides, some treatments can be used carefully according to the selectivity. But for soil insecticide treatments, their toxicity raise the question of their use in IPM programs in vegetables and the need of new compounds or development of alternative pest control programs.

Selectivity lists of pesticides to beneficial arthropods for IPM programs in carrot--first results.

In order to improve IPM programs in carrot, 7 fungicides, 12 herbicides and 9 insecticides commonly used in Belgium were tested for their toxicity towards five beneficial arthropods representative of most important natural enemies encountered in carrot: parasitic wasps - Aphidius rhopalosiphi (De Stefani-Perez) (Hym., Aphidiidae), ladybirds - Adalia bipunctata (L.) (Col., Coccinellidae), hoverfly - Episyrphus balteatus (Dipt.. Syrphidae), rove beetle - Aleochara bilineata (Col., Staphylinidae) and carabid beetle - Bembidion lampros (Col., Carabidae). Initialy, all plant protection products were tested on inert substrate glass plates or sand according to the insect. Products with a corrected mortality (CM) or a parasitism reduction (PR) lower than 30% were kept for the constitution of positive list (green list). The other compounds were further tested on plant for A. rhopalosiphi, A. bipunctata, E. balteatus and soil for B. lampros and A. bilineata. With these extended laboratory tests results, products were listed in toxicity class: green category [CM or PR < or = 30%], yellow category [30% < CM or PR < or = 60%] and orange category [60% < CM or PR < or = 80%]. Products with toxicity higher than 80% on plants or that reduce parasitism more than 80% on soil were put in red category and are not recommended to Integrated Pest Management programs in carrot. Results showed that all fungicides tested were harmless to beneficials except Tebuconazole, which was slightly harmful for A. bipunctata. Herbicides were also harmless for soil beneficials, except Chlorpropham. This product was very toxic on sand towards A. bilineata and must be tested on soil. All soil insecticides tested were very toxic for ground beneficials and considered as non-selective. Their use in IPM is subject to questioning in view of negative impacts on beneficials. Among foliar insecticides, Dimethoate and Deltamethrin are not recommended for IPM because their high toxicity for all beneficials. The other foliar insecticides were more selective; any of them were harmless for all species tested.

Determination of 22 triazole compounds including parent fungicides and metabolites in apples, peaches, flour, and water by liquid chromatography/tandem mass spectrometry.

A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed for the determination of 14 parent triazole fungicides and 8 of their metabolites found in apples, peaches, flour, raw water, and tap water. The triazole fungicides chosen for this multiresidue method development project included propiconazole, fenbuconazole and its RH-9129 and RH-9130 metabolites, cyproconazole, difenoconazole, tebuconazole and its HWG 2061 metabolite, hexaconazole, bromuconazole (both stereoisomers), epoxiconazole, tetraconazole, triticonazole and its RPA-404886 and RPA-406341 metabolites, triadimefon, triadimenol, and myclobutanil. Of special concern to the U.S. Environmental Protection Agency were the metabolites common to all triazole fungicides: free triazole, 1,2,4-triazole (T), and its 2 conjugates: triazolylalanine (TA) and triazolylacetic acid (TAA). These metabolites were the primary focus of this project. All samples we cleaned up by a combination of C18 solid-phase extraction (SPE), mixed-mode cationic SPE, and mixed-mode anionic SPE columns. A triple-stage quadrupole mass spectrometer, equipped with electrospray ionization in the positive-ion mode, was used to determine the compounds of interest. T, TA, and TAA were quantitated using isotopically labeled internal standards (IS), in which the 1,2,4-triazole ring had been synthesized by using 13C and 15N (IS_T, IS_TA, and IS_TAA). These isotopically labeled internal standards were necessary to correct for matrix effects. The T, TA, and TAA metabolites were quantitated at the 25-50 parts-per-billion (ppb) level in food commodities and at 0.50 ppb in water. Recoveries were 70-101% from apples, 60-121% from peaches, 57-118% from flour, 75-99% from raw water, and 79-99% from tap water.