Use Of Fungicides In Agriculture Research Articles

Prevalence of Azole-Resistant Aspergillus fumigatus is Highly Associated with Azole Fungicide Residues in the Fields.

Triazole resistance in Aspergillus fumigatus is a growing public health concern. In addition to its emergence in the therapy of invasive aspergillosis by triazole medicines, it has been frequently detected in agricultural fields all over the world. Here, we explore the potential link between residues of azole fungicides with similar chemical structure to triazole medicines in soil and the emergence of resistant A. fumigatus (RAF) through 855 500 km2 monitoring survey in Eastern China covering 6 provinces. In total, 67.3%, 15.2%, 12.3%, 2.9%, 1.5%, 0.4%, and 0.3% of the soil samples contained these five fungicides (tebuconazole, difenoconazole, propiconazole, hexaconazole, and prochloraz) of 0-100, 100-200, 200-400, 400-600, 600-800, 800-1000, and >1000 ng/g, respectively. The fractions of samples containing RAF isolates were 2.4%, 5.2%, 6.4%, 7.7%, 7.4%, 14.3%, and 20.0% of the samples with total azole fungicide residues of 0-100, 100-200, 200-400, 400-600, 600-800, 800-1000, and >1000 ng/g, respectively. We find that the prevalence of RAFs is positively (P < 0.0001) correlated with residual levels of azole fungicides in soils. Our results suggest that the use of azole fungicides in agriculture should be minimized and the intervals between treatments expanded to reduce the selective pressure toward the development of resistance in A. fumigatus in agricultural fields.

Effects of Agricultural Fungicide Use on Aspergillus fumigatus Abundance, Antifungal Susceptibility, and Population Structure.

Antibiotic resistance is an increasing threat to human health. In the case of Aspergillus fumigatus, which is both an environmental saprobe and an opportunistic human fungal pathogen, resistance is suggested to arise from fungicide use in agriculture, as the azoles used for plant protection share the same molecular target as the frontline antifungals used clinically. However, limiting azole fungicide use on crop fields to preserve their activity for clinical use could threaten the global food supply via a reduction in yield. In this study, we clarify the link between azole fungicide use on crop fields and resistance in a prototypical human pathogen through systematic soil sampling on farms in Germany and surveying fields before and after fungicide application. We observed a reduction in the abundance of A. fumigatus on fields following fungicide treatment in 2017, a finding that was not observed on an organic control field with only natural plant protection agents applied. However, this finding was less pronounced during our 2018 sampling, indicating that the impact of fungicides on A. fumigatus population size is variable and influenced by additional factors. The overall resistance frequency among agricultural isolates is low, with only 1 to 3% of isolates from 2016 to 2018 displaying resistance to medical azoles. Isolates collected after the growing season and azole exposure show a subtle but consistent decrease in susceptibility to medical and agricultural azoles. Whole-genome sequencing indicates that, despite the alterations in antifungal susceptibility, fungicide application does not significantly affect the population structure and genetic diversity of A. fumigatus in fields. Given the low observed resistance rate among agricultural isolates as well the lack of genomic impact following azole application, we do not find evidence that azole use on crops is significantly driving resistance in A. fumigatus in this context.IMPORTANCE Antibiotic resistance is an increasing threat to human health. In the case of Aspergillus fumigatus, which is an environmental fungus that also causes life-threatening infections in humans, antimicrobial resistance is suggested to arise from fungicide use in agriculture, as the chemicals used for plant protection are almost identical to the antifungals used clinically. However, removing azole fungicides from crop fields threatens the global food supply via a reduction in yield. In this study, we survey crop fields before and after fungicide application. We find a low overall azole resistance rate among agricultural isolates, as well as a lack of genomic and population impact following fungicide application, leading us to conclude azole use on crops does not significantly contribute to resistance in A. fumigatus.

Fungicide-Tolerant Plant Growth-Promoting Rhizobacteria Mitigate Physiological Disruption of White Radish Caused by Fungicides Used in the Field Cultivation.

Excessive use of fungicides in agriculture may result in substantial accumulation of active residues in soil, which affect crop health and yield. We investigated the response of Raphanus sativus (white radish) to fungicides in soil and potential beneficial interactions of radish plants with fungicide-tolerant plant growth-promoting rhizobacteria (PGPR). The PGPR were isolated from cabbage and mustard rhizospheres. Morphological and biochemical characteristics measured using standard methods, together with analysis of partial 16S rRNA gene sequences, revealed that fungicide-tolerant PGPR, isolates PS3 and AZ2, were closely related to Pseudomonas spp. These PGPR survived in the presence of high fungicide concentrations i.e., up to 2400 μg mL−1 carbendazim (CBZM) and 3200 μg mL−1 hexaconazole (HEXA). Bacterial isolates produced plant growth stimulants even under fungicide stress, though fungicides induced surface morphological distortion and alteration in membrane permeability of these bacteria, which was proved by a set of microscopic observations. Fungicides considerably affected the germination efficiency, growth, and physiological development of R. sativus, but these effects were relieved when inoculated with PGPR isolates. For instance, CBZM at 1500 mg kg−1 decreased whole dry biomass by 71%, whole plant length by 54%, total chlorophyll by 50%, protein content by 61%, and carotenoid production by 29%. After applying isolate AZ2 for white radish grown in CBZM (10 mg kg−1)-amended soil, it could improve plant growth and development with increased whole plant dry weight (10%), entire plant length (13%) and total chlorophyll content (18%). Similarly, isolate PS3 enhanced plant survival by relieving plant stress with declined biomarkers, i.e., proline (12%), malondialdehyde (3%), ascorbate peroxidase (6.5%), catalase (18%), and glutathione reductase (4%). Application of isolates AZ2 and PS3 could be effective for remediation of fungicide-contaminated soil and for improving the cultivation of radish plants while minimizing inputs of fungicides.

Calcium disodium ethylenediaminetetraacetate as a safe compound for crop protection with the potential to extend the basic substances group

Excessive use of commercial synthetic fungicides in agriculture is a globally discussed issue. This topic is seen as particularly important in modern plant protection and cultivation systems, where the total fungicide burden of the agroecosystem should be controlled and reduced. Basic substances (BSs) are a relatively novel, legally recognised group of substances which can be applied. The present study tested calcium disodium ethylenediaminetetraacetate (CaNa&lt;sub&gt;2&lt;/sub&gt;-EDTA), a substance whose properties and environmental safety make it another useful alternative for plant protection in modern farming. The study demonstrated the high antifungal activity of the substance against Pyrenophora (anamorph: Drechslera) tritici-repentis (Died.) Drechsler, (MIC50 0.195–0.223 mg/ml), safety for plant tissue and especially for non-target organisms, and positive effects on the yield of wheat (Triticum aestivum Linnaeus). CaNa&lt;sub&gt;2&lt;/sub&gt;-EDTA surpassed the effect of chitosan hydrochloride, a registered and utilised substance, and a synthetic conventional fungicide. CaNa&lt;sub&gt;2&lt;/sub&gt;-EDTA is an excellent candidate for registering within the BS group, with benefits for environmentally sound systems in plant protection.

Effect of Different Copper Levels on Growth and Morpho-Physiological Parameters in Giant Reed (Arundo donax L.) in Semi-Hydroponic Mesocosm Experiment

In Mediterranean countries, the use of copper-based fungicides in agriculture is causing a concerning accumulation of copper in the upper layer (0–20 cm) of soils and water bodies. Phytoremediation by energy crops offers the chance to associate the recovering of polluted environments with the production of biomass for bioenergy purposes. The purpose of this work was to evaluate the morpho-physiological response of giant reed (Arundo donax L.), a well-known energy crop, when treated with increasing concentrations of Cu (0, 150, and 300 ppm) in a semi-hydroponic growing system (mesocosm) for one month. The plant morphology (height and base diameter of the stem, number of stems) was not affected by the treatments. The presence of Cu led to the disequilibrium of Fe and Zn foliar concentration and caused an impairment of photosynthetic parameters: at 150 and 300 ppm the chlorophyll content and the ETR were significantly lower than the control. The study demonstrated that, although the presence of Cu may initially affect the plant physiology, the Arundo plants can tolerate up to 300 ppm of Cu without any adverse effect on biomass production, even when grown in semi-hydroponic conditions.

Resistance in the Environmental Pathogenic Fungus Aspergillus fumigatus.

Aspergillus fumigatus, an opportunistic pathogenic fungus, is common in the environment. Azole-resistant strains of A. fumigatus have recently been discovered in the environment. Acquisition of azole resistance has been considered to occur through unexpected selection due to fungicide use in agriculture. This review discusses the relationships of humans with A. fumigatus in the environment and the importance of anthropogenic activities in the spread of A. fumigatus worldwide.

Azole-resistant Aspergillus fumigatus in the Italian environment.

Azole resistance in Aspergillus fumigatus environmental and clinical isolates is recognised as an emerging problem worldwide. Development of azole resistance may be environmentally driven because of the massive use of azole fungicides in agriculture. The mechanism of azole resistance is mostly related to mutations in the cyp51A gene. A. fumigatus azole resistance in the environment was previously documented in northern Italy. This study extended the research in the agricultural environment also in central and southern Italy and investigated differences in the Italian geographical areas and in the different types of crops. A total of 177 samples (173 soil samples and 4 Dutch bulbs) collected in the period 2014-20117 in 14 Italian regions were analysed. Itraconazole-resistant A. fumigatus isolates grew in 16.9% of the screened samples. Differences were observed in soil samples from the three Italian geographic areas: 12.5% in the north, 15.2% in the centre and 24.1% in the south. Resistant isolates were from different cultivations, treated or officially not treated with azole fungicides. Sequencing of the cyp51A gene confirmed that resistance was mainly associated with the TR34/L98H mutation (29/30 isolates); 1 isolate showed the G54E mutation. The risk for patients to acquire multi-azole-resistant strains from the environment could have a serious impact on the management of life-threatening invasive infections. The azole resistance rate of 16.9% found in Italy requires suitable monitoring of antifungal susceptibility of clinical isolates.

Triazole-Resistant Aspergillus fumigatus from Fungicide-Experienced Soils in Naivasha Subcounty and Nairobi County, Kenya.

The mainstay in prevention and treatment of aspergillosis is the use triazole drugs. In Kenya, the use of agricultural azole is one of the predisposing factors in development of resistance. One hundred fifty-six (156) experienced soils were collected from agricultural farms and cultured on Sabouraud DextroseAagar. The study isolated 48 yielded Aspergillus fumigatus and 2 A. flavus. All the isolates were subjected to antifungal susceptibility testing against three triazoles: posaconazole, voriconazole, and itraconazole. Out of the isolates, 3 had MIC of 32 and 1 had MIC of 16 against itraconazole, and 1 isolate had MIC of 32 against posaconazole. CYP51A gene was sequenced, and TR34/L98H mutation was identified. Triazole resistance existing in Kenya calls for rational use of azole-based fungicides in agriculture over concerns of emerging antifungal resistance in clinical practice.

Elevated MIC Values of Imidazole Drugs against Aspergillus fumigatus Isolates with TR 34 /L98H/S297T/F495I Mutation

The use of azole fungicides in agriculture is believed to be one of the main reasons for the emergence of azole resistance in Aspergillus fumigatus Though widely used in agriculture, imidazole fungicides have not been linked to resistance in A. fumigatus This study showed that elevated MIC values of imidazole drugs were observed against A. fumigatus isolates with TR34/L98H/S297T/F495I mutation, but not among isolates with TR34/L98H mutation. Short-tandem-repeat (STR) typing analysis of 580 A. fumigatus isolates from 20 countries suggested that the majority of TR34/L98H/S297T/F495I strains from China were genetically different from the predominant major clade comprising most of the azole-resistant strains and the strains with the same mutation from the Netherlands and Denmark. Alignments of sterol 14α-demethylase sequences suggested that F495I in A. fumigatus was orthologous to F506I in Penicillium digitatum and F489L in Pyrenophora teres, which have been reported to be associated with imidazole resistance. In vitro antifungal susceptibility testing of different recombinants with cyp51A mutations further confirmed the association of the F495I mutation with imidazole resistance. In conclusion, this study suggested that environmental use of imidazole fungicides might confer selection pressure for the emergence of azole resistance in A. fumigatus.

Pesticide behavior in paddy fields and development of azole-resistant Aspergillus fumigatus: Should we be concerned?

Tricyclazole as a common fungicide wildly used to control rice blast disease in the Asian country may induce azole resistance in Aspergillus fumigatus isolates. The main reason of the acquired azole resistance is probably environmental exposure through wide fungicide use in agriculture. The present study was conducted with the aim of investigating the current status of the azole-resistant A. fumigatus obtained from the paddy fields with exposure to tricyclazole. A total of 108 soil samples were collected from four different locations of paddy fields in Mazandaran Province, Iran. Pure fungal colonies were initially identified based on the conventional tools, and then reconfirmed by using DNA sequencing of the partial ß-tubulin gene. In addition, the in vitro antifungal susceptibility was determined using the Clinical and Laboratory Standards Institute document (CLSI) M38-A2. The identification of the mutations in the CYP51A gene was accomplished by the implementation of the polymerase chain reaction amplification assay on the selected isolates. Overall, 31 of 108 (28.7%) isolates were identified as A.fumigatus, four (3.7%) of which were recognized as azole-resistant with MICs of itraconazole ≥8μg/ml and voriconazole ≥4μg/ml. Only two out of the four azole-resistant A. fumigatus isolates harboured TR34/L98H variant and the other two isolates were identified as azole-resistant without any CYP51A gene mutations. However, other point mutations (TR46/Y121F/T289A) were not detected in the CYP51A gene. The high molecular structure similarity between environmental and medical triazoles may result in the selection of resistance mechanisms. Nonetheless, one might conclude that tricyclazole with different molecular structures against medical azoles induces azole-resistance in A.fumigatus isolates. The behavior of such pesticides as tricyclazole in the rice paddy fields would have an effective role in the development of azole-resistance that requires detailed information.

Prevalence of azole-resistant Aspergillus fumigatus in the environment of Thailand.

Occurrence of azole-resistant Aspergillus fumigatus (ARAF) in the environment is an emerging problem worldwide, likely impacting on patient treatment. Several resistance mutations are thought to have initially arisen through triazole-based fungicide use in agriculture and subsequently being propagated in a similar manner. Here we investigated the prevalence of ARAF in the environment of Thailand and characterized their susceptibility profiles toward clinically used azole compounds along with underlying resistance mutations. Three hundred and eight soil samples were collected and analyzed, out of which 3.25% (n = 10) were positive for ARAF. All isolates obtained were resistant to itraconazole (MIC ≥ 8μg/ml), two showed additional increased MIC values toward posaconazole (MIC = 0.5μg/ml), and one other toward voriconazole (MIC = 2μg/ml). Sequencing of the respective cyp51A genes revealed that eight of the isolates carried the TR34/L98H allele and those two with elevated MIC values to posaconazole the G54R substitution. Although a clear correlation between the use of triazole-based fungicides and isolation of ARAF strains from agricultural lands could not be established for Thailand, but this study clearly demonstrates the spread of globally observed ARAF strains to the environment of South East Asia.

Early life exposure to a rodent carcinogen propiconazole fungicide induces oxidative stress and hepatocarcinogenesis in medaka fish

Conazole pollution is an emerging concern to human health and environmental safety because of the broad use of conazole fungicides in agriculture and medicine and their frequent occurrence in aquifers. The agricultural pesticide propiconazole has received much regulatory interest because it is a known rodent carcinogen with evidence of multiple adverse effects in mammals and non-targeted organisms. However, the carcinogenic effect and associated mechanism of propiconazole in fish under microgram-per-liter levels of environmental-relevant exposure remains unclear. To explore whether early life of propiconzaole exposure would induce oxidative stress and latent carcinogenic effects in fish, we continuously exposed larvae of wild type or p53−/− mutant of medaka fish (Oryzias latipes) to propiconazole (2.5–250μg/L) for 3, 7, 14 or 28 days and assessed liver histopathology and/or the oxidative stress response and gene expression during exposure and throughout adulthood. Propiconazole dose-dependently induced reactive oxygen species (ROS) level, altered homeostasis of antioxidant superoxide dismutase, catalase and glutathione S-transferase and caused lipid and protein peroxidation during early life exposure in wild type medaka. Such exposure also significantly upregulated gene expression of the cytochrome P450 CYP1A, but marginally suppressed that of tumor suppressor p53 in adults. Furthermore, histopathology revealed that p53−/− mutant medaka with early life exposure to propiconazole showed increased incidence of hepatocarcionogensis, as compared to the p53−/− control group and wild type strain. We demonstrated that propiconazole can initiate ROS-mediated oxidative stress and induce hepatic tumorigenesis associated with CYP1A- and/or p53 -mediated pathways with the use of wild type and p53−/− mutant of medaka fish. The toxic response of medaka to propiconazole is compatible with that observed in rodents.

Identificação molecular e fenotípica de bactérias de solo rizosférico com tolerância ao fungicida Mancozeb, em Manaus, Estado do Amazonas, Brasil

A utilizacao de fungicidas na agricultura tem se intensificado, causando grande impacto nos solos e na biota em que eles se encontram. A presenca desses compostos no solo vem acarretando modificacoes no comportamento dos microrganismos, que passaram a adquirir estrategias de sobrevivencia a presenca desses produtos. O Mancozeb e um fungicida do grupo dos carbamatos, cuja acao pelo contato inativa as enzimas essenciais dos fungos. Os objetivos deste trabalho foram: isolar bacterias de solo; caracterizar os isolados com ensaios bioquimicos e ferramentas moleculares; obter o crescimento dos isolados em meio minimo acrescido do fungicida; e estabelecer uma colecao de bacterias com potencial de biorremediacao. As bacterias foram isoladas a partir de tecnicas de isolamento em dois meios de cultura diferentes: meio minimo e meio Bushneel Haas acrescidos de 3,6 gL-1 de Mancozeb. Realizou-se a identificacao por meio da caracterizacao fenotipica, utilizando-se de ensaios bioquimicos para determinar o genero e identificacao molecular pelo emprego do sequenciamento da regiao 16S, com os iniciadores 1492R, 513F, os quais amplificam 1.000 pares de base. Os 11 isolados de bacterias foram identificados em quatro familias, quatro generos e 11 especies. A familia Bacillaceae foi a mais representativa, com 81,81% dos isolados. Esses ensaios permitiram verificar a tolerância das bacterias isoladas em concentracoes superiores as usadas em campo para o controle de pragas. A colecao de microrganismos decorrentes da realizacao dessa pesquisa podera servir para estudos futuros envolvendo a biodegradacao de xenobioticos.

Antifungal Activity of Volatile Compounds Produced by an Edible Mushroom Hypsizygus marmoreus against Phytopathogenic Fungi

AbstractVolatile compounds with antifungal activity produced by edible mushrooms have potential as biological control agents to combat fungal diseases and reduce fungicide use in agriculture. Here we investigated the antifungal activity of volatile compounds produced by the edible mushroom Hypsizygus marmoreus (TUFC 11906) against eight phytopathogenic fungi. The results showed that volatile compounds from the mycelia and culture filtrates (CFs) of H. marmoreus had antifungal activity against some phytopathogenic fungi. Among them, the mycelial growth and conidial germination of Alternaria brassicicola were significantly inhibited by 60 and 100%, respectively. Moreover, the volatile compounds from CFs inhibited the lesion formation of A. brassicicola on detached cabbage leaves by 94%. The volatile compounds had higher antifungal activity against A. brassicicola than other fungi. With the removal of the volatile compounds from conidia of A. brassicicola, the conidia began to germinate, which indicates fungistatic activity of the compounds. The volatile compounds were isolated from the CFs of H. marmoreus, and the major volatile compound with antifungal activity was estimated to be 2‐methylpropanoic acid 2,2‐dimethyl‐1‐(2‐hydroxy‐1‐methylethyl)propyl ester. As the volatile compound produced by H. marmoreus is a product of an edible mushroom and has fungistatic activity against some phytopathogenic fungi, especially A. brassicicola, it may be possible to use the compounds as a novel safe agent for protecting crops in the field and during storage.

Ecotoxicological impacts of isoprothiolane on freshwater fish Cyprinus carpio fingerlings: a multi-biomarker assessment

Extensive use of fungicides in agriculture has led to the detrimental effects on aquatic ecosystems and organisms even at very low concentrations. In this respect, the present study was aimed to investigate the impact of environmentally relevant concentrations of fungicide isoprothiolane (2.7 and 27 µg/L; reported concentration in Yung San River, Korea) on a freshwater fish Cyprinus carpio for a short-term period of 96 h using various biomarkers such as hematological, ionoregulatory, biochemical, and enzymological parameters. At both concentrations, hemoglobin, hematocrit, red blood cell, serum glucose, cholesterol, triglycerides, aspartate aminotransferase, and gill Na+/K+-ATPase levels were significantly (p < 0.05) decreased in fish treated with isoprothiolane. Contrastingly, white blood cell, serum sodium (Na+), chloride (Cl−), and albumin levels were increased (p < 0.05). However, the short-term exposure of isoprothiolane in carp resulted in slight alterations in mean cellular volume, mean cellular hemoglobin, mean cellular hemoglobin concentration, serum potassium (K+), protein, globulin, and alkaline phosphatase levels. The present study concludes that alterations of hematological, ionoregulatory, biochemical, and enzymological parameters can be used as efficient biomarkers in monitoring the toxicity of isoprothiolane as well as other pesticides in aquatic organisms. Further, more detailed studies on using of specific biomarkers to monitor the long-term effects of isoprothiolane are needed.

Clustering of two genes putatively involved in cyanate detoxification evolved recently and independently in multiple fungal lineages.

Fungi that have the enzymes cyanase and carbonic anhydrase show a limited capacity to detoxify cyanate, a fungicide employed by both plants and humans. Here, we describe a novel two-gene cluster that comprises duplicated cyanase and carbonic anhydrase copies, which we name the CCA gene cluster, trace its evolution across Ascomycetes, and examine the evolutionary dynamics of its spread among lineages of the Fusarium oxysporum species complex (hereafter referred to as the FOSC), a cosmopolitan clade of purportedly clonal vascular wilt plant pathogens. Phylogenetic analysis of fungal cyanase and carbonic anhydrase genes reveals that the CCA gene cluster arose independently at least twice and is now present in three lineages, namely Cochliobolus lunatus, Oidiodendron maius, and the FOSC. Genome-wide surveys within the FOSC indicate that the CCA gene cluster varies in copy number across isolates, is always located on accessory chromosomes, and is absent in FOSC’s closest relatives. Phylogenetic reconstruction of the CCA gene cluster in 163 FOSC strains from a wide variety of hosts suggests a recent history of rampant transfers between isolates. We hypothesize that the independent formation of the CCA gene cluster in different fungal lineages and its spread across FOSC strains may be associated with resistance to plant-produced cyanates or to use of cyanate fungicides in agriculture.

Resistance to antifungals that target CYP51.

Fungal diseases are an increasing global burden. Fungi are now recognised to kill more people annually than malaria, whilst in agriculture, fungi threaten crop yields and food security. Azole resistance, mediated by several mechanisms including point mutations in the target enzyme (CYP51), is increasing through selection pressure as a result of widespread use of triazole fungicides in agriculture and triazole antifungal drugs in the clinic. Mutations similar to those seen in clinical isolates as long ago as the 1990s in Candida albicans and later in Aspergillus fumigatus have been identified in agriculturally important fungal species and also wider combinations of point mutations. Recently, evidence that mutations originate in the field and now appear in clinical infections has been suggested. This situation is likely to increase in prevalence as triazole fungicide use continues to rise. Here, we review the progress made in understanding azole resistance found amongst clinically and agriculturally important fungal species focussing on resistance mechanisms associated with CYP51. Biochemical characterisation of wild-type and mutant CYP51 enzymes through ligand binding studies and azole IC50 determinations is an important tool for understanding azole susceptibility and can be used in conjunction with microbiological methods (MIC50 values), molecular biological studies (site-directed mutagenesis) and protein modelling studies to inform future antifungal development with increased specificity for the target enzyme over the host homologue.

Azole-Resistant Invasive Aspergillosis: Relationship to Agriculture

Azole resistance in Aspergillus fumigatus has been increasingly reported particularly over the last decade. Two routes of acquisition are described: selection of resistance during long term azole therapy in the clinical setting, and primary acquisition of resistant isolates from the environment due to the considerable use of azole fungicides in agriculture and for material preservation. Three specific resistance genotypes have been found in azole naive patients. Two of these have also been found in the environment and are characterized by a tandem repeat in the promoter region of the target gene coupled with point mutation(s) in CYP51A (TR34/L98H and TR46/Y121F/T289A). In the third a single target enzyme alteration (G432S) is found. These resistant “environmental” strains have been detected in many West-European countries as well as in the Asia-Pacifics. Noticeably, these two continents account for the highest fungicide use in the global perspective (37 % and 24 %, respectively). Among the 25 azole fungicides, five have been associated with the potential to select for the TR34/L98H genotype; three of these are among those most frequently used. Although the number of antifungal fungicide compounds and classes available is impressive compared to the armamentarium in human medicine, azoles will remain the most important group in agriculture due to superior field performance and significant resistance in fungal pathogens to other compounds. Hence, further spread of environmental resistant Aspergillus genotypes may occur and will depend on the fitness of each resistant phenotype and the pattern of azole fungicide use.

Phytotoxicity: An Overview of the Physiological Responses of Plants Exposed to Fungicides

In the last decades, the use of fungicides in agriculture for fungi diseases control has become crucial. Fungicide research has produced a diverse range of products with novel modes of action. However, the extensive use of these compounds in the agriculture system raises public concern because of the harmful potential of such substances in the environment and human health. Moreover, the phytotoxic effects of some fungicides are already recognized but little is known about the impact of these compounds on the photosynthetic apparatus. This paper presents a comprehensive overview of the literature considering different classes of fungicides and their effects on plant physiology, with particular emphasis on photosynthesis.

A review on bioactive compounds isolated from plants against plant pathogenic fungi

Plant-derived compounds are regarded as a substantial source for novel lead structures to develop medicines and biocides natural products. Concurrent with greater awareness towards the use of synthetic chemicals in agricultural practice, the application of integrated pest management programs has also increased. In recent years, there has been considerable public pressure to reduce the use of synthetic fungicides in agriculture. Although, the use of synthetic fungicides in plant disease control has been successful in improving agricultural output, several of these have been found to exhibit side-effects in the form of carcinogenicity, detrimental effects and other residual toxicities. The alternative choice therefore would be the use of botanical fungicides, which are found to be largely non-phytotoxic, systematic and easily biodegradable in nature. The present study is a summary of review literature during past decades which focused on bioactive compounds isolated from plants against plant pathogenic fungi. Key words: Bioactive compounds, secondary metabolites, plant pathogenic fungi, plant extracts.