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Terpenes represent the biggest group of natural compounds on earth. This large class of organic hydrocarbons is distributed among all cellular organisms, including fungi. The different classes of terpenes produced by fungi are mono, sesqui, di- and triterpenes, although triterpene ergosterol is the main sterol identified in cell membranes of these organisms. The availability of genomic data from members in the Ceratocystidaceae enabled the detection and characterization of the genes encoding the enzymes in the mevalonate and ergosterol biosynthetic pathways. Using a bioinformatics approach, fungal orthologs of sterol biosynthesis genes in nine different species of the Ceratocystidaceae were identified. Ergosterol and some of the intermediates in the pathway were also detected in seven species (Ceratocystis manginecans, C. adiposa, Huntiella moniliformis, Thielaviopsis punctulata, Bretziella fagacearum, Endoconidiophora polonica and Davidsoniella virescens), using gas chromatography-mass spectrometry analysis. The average ergosterol content differed among different genera of Ceratocystidaceae. We also identified all possible terpene related genes and possible biosynthetic clusters in the genomes used in this study. We found a highly conserved terpene biosynthesis gene cluster containing some genes encoding ergosterol biosynthesis enzymes in the analysed genomes. An additional possible terpene gene cluster was also identified in all of the Ceratocystidaceae. We also evaluated the sensitivity of the Ceratocystidaceae to a triazole fungicide that inhibits ergosterol synthesis. The results showed that different members of this family behave differently when exposed to different concentrations of triazole tebuconazole. [ABSTRACT FROM AUTHOR]

The onion basal rot disease is a worldwide threat caused by species of the genus Fusarium. Today, Israel’s control of this disease is limited to a four-year growth cycle and Metam sodium soil disinfection. Here, commercial chemical fungicides were evaluated as control treatments against two of the primary pathogens involved, F. oxysporum f. sp. cepae and F. Acutatum. Out of 10 fungicides tested on culture plates, 3, Prochloraz, Azoxystrobin + Tebuconazole, and Fludioxonil + Sedaxen, had strong inhibitory effects on mycelial growth and were selected and tested in seeds in vitro. The preparations were applied as a seed coating and tested in two commercial cultivars, Riverside (Orlando, white cv.) and Noam (red cv.). Prochloraz (0.3% w/w concentration), the most promising compound, was efficient in reducing the Noam cv. sprouts’ disease symptoms. This preparation had no harmful in situ-toxicity effect and did not influence the plants’ seed germination and early development. In Noam cv. potted 30-day-old sprouts, the Prochloraz treatment was able to reduce the harmful impact of F. oxysporum f. sp. cepae. on the seedlings’ wet biomass, but was not effective in the Riverside cv. or against the F. acutatum pathogen. This suggests that future protective strategies must include an effective protective suit tailored to each of the pathogen species involved and the onion cultivar. The methods presented in this work can be applied for rapidly scanning multiple compounds while gradually ruling out ineffective ones. Eventually, this screening will enable field testing of the highest potential fungicides that successfully pass the pot experiments. [ABSTRACT FROM AUTHOR]

Copyright of Espirales Revista Multidisciplinaria de Investigación is the property of Grupo Compas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Wheat powdery mildew (PM) is one of the world's top 10 most destructive fungal plant pathogen and the routine control of this disease is by application of fungicides and disease-resistant cultivars. In this study, a nanocomposite composed of amino silicon oil (ASO) and palygorskite (Pal) was developed and can effectively inhibit the pathogen. The results demonstrated that the morphology and microstructure of Pal could be effectively modified by ASO via hydrogen bonds between –NH 2 of ASO and − OH of Pal, resulting in an increase of hydrophobic surface groups. Further analysis showed that nanonetworks were formed by Pal-ASO interaction, which could effectively segregate Blumeria graminis f. sp. tritici (Bgt) conidia from wheat leaf surface and reduce the disease index by 98%. This work provides an economic and environmentally friendly approach to control the wheat powdery mildew disease. Highlights • The microstructure of palygorskite (Pal) could be modified by amino silicon oil (ASO). • Application of Pal-ASO composite (CAA) can reduced the disease index of powdery mildew in wheat. • CAA showed no significant toxicity to Bgt conidia and no negative effects on the wheat growth. [ABSTRACT FROM AUTHOR]

Abstract Phytophthora infestans is one of the most notorious pathogen among Phytophthora species causing potato late blight disease. Stable and long-term preservation of this pathogen is essential for biological research and fungicide screening. The aim of this study was to find a suitable long-term preservation method for P. infestans. We adjusted the storage temperature, made a slight modification to the rye seed method, and compared the influence of four preservation methods (the mineral oil method, the sterile water method, the rye seed method, and the modified rye seed method) on survival, growth and virulence of four isolates of P. infestans. The results showed that all four methods maintained high viability of the tested P. infestans isolates, but the two rye seed methods were the best ways to maintain 100% viability of the P. infestans isolates without contamination. The four preservation methods did not significantly influence growth or morphological characteristics of the P. infestans isolates. The impacts of the four methods on the virulence of the four P. infestans isolates were isolate-specific. For isolates YF3 and 64093, all four methods were suitable for maintaining their virulence. Whilst for isolate HQK8–3, the rye seed and sterile water methods were more suitable to maintain its virulence than the other two methods. For isolate 32835, storage under mineral oil was the best method for maintaining its virulence. In view of these results, it is recommended P. infestans should be stored by several different storage methods to ensure the safety and stability of the isolates. Highlights • A stable and long-term preservation method is essential for Phytophthora infestans. • The four methods can maintain a high viability of P. infestans. • The four methods have no influence on the growth and morphology of the species. • The influence of the four methods on the pathogenicity were isolate-specific. • The isolates of P. infestans should be stored by several different storage methods. [ABSTRACT FROM AUTHOR]

In Spain, management of the cucurbit powdery mildew pathogen Podosphaera xanthii is strongly dependent on chemicals such as quinone outside inhibitor (QoI) fungicides. In a previous report, widespread resistance to QoI fungicides in populations of P. xanthii in south-central Spain was documented, but the molecular mechanisms of resistance remained unclear. In this work, the role of the Rieske-FeS (risp) and the cytochrome b (cytb) gene mutations in QoI resistance of P. xanthii were examined. No point mutations in the risp gene were found in the three QoI-resistant isolates analyzed. For cytb, sequence analysis revealed the presence of a G143A substitution that occurs in many QoI-resistant fungi. This mutation was always detected in QoI-resistant isolates of P. xanthii; however, it was also detected in sensitive isolates. To better understand the role of heteroplasmy for cytb in QoI resistance of P. xanthii, an allele-specific quantitative PCR was developed to quantify the relative abundance of the G143 (sensitive) and A143 (resistant) alleles. High relative abundance of A143 allele (70%) was associated with isolates resistant to QoI fungicides; however, QoI-sensitive isolates also carried the mutated allele in frequencies ranged from 10 to 60%. Our data suggest that G143A mutation in cytb is the primary factor involved in QoI resistance of P. xanthii but the proportion of G143 and A143 alleles in an isolate may determine its QoI resistance level. [ABSTRACT FROM AUTHOR]

Harmful chemicals predominantly used in modern agriculture for pest control have raised a long-term accumulation in the environment and serious problems concerning food safety and health. Excellent detection tools for environmental monitoring are thus urgently needed. The recent biosensor technology is proposed to fulfill this purpose. In this study, an expedient biosensor for captan fungicide determination has been fabricated using its specific reacting enzyme glutathione-s-transferase (GST) covalently immobilized on natural biopolymer chitosan (Chi). The screen-printed carbon electrode (SPCE) has been selected as a basal platform for the biosensor development. Modification of SPCE was made by self-assembled deposition of 1% chitosan in 1% acetic acid solution onto the basal SPCE. Progressive characteristics of the assembled SPCE-Chi-GST have been clearly approved by atomic force microscopy, impedance spectroscopy and cyclic voltammetry (CV). Two sequential oxidation peak currents arose in the electrochemical behavior analysis of captan in the presence of GST substrate electrolyte solution by CV and linear sweep voltammetry (LSV). Dose-response to various captan concentrations was investigated in the range 0 - 20 µg/ml by LSV and a similar good linear relationship between peak current and concentration of captan could be obtained by both oxidation steps with the limit of detection (LOD) at 0.2 µg/ml. Thus the sensitive, rapid, inexpensive and miniature quantitative system for captan monitoring could now be successfully achieved by this proposed biosensor. [ABSTRACT FROM AUTHOR]

Understanding the effects of fungicides on nontarget organisms at realistic concentrations and exposure durations is vital for determining potential impacts on aquatic ecosystems. Environmental concentrations of the fungicide azoxystrobin have been reported up to 4.6 μg/L in the United States and 30 μg/L in Europe. The objective of the present study was to evaluate the chronic toxicity of azoxystrobin in water-only exposures with an amphipod ( Hyalella azteca; 42-d exposure), a midge ( Chironomus dilutus; 50-d exposure), a cladoceran ( Ceriodaphnia dubia; 7-d exposure), and a unionid mussel ( Lampsilis siliquoidea; 28-d exposure) at environmentally relevant concentrations. The potential photo-enhanced toxicity of azoxystrobin accumulated by C. dubia and L. siliquoidea following chronic exposures to azoxystrobin was also evaluated. The 20% effect concentrations (EC20s) based on the most sensitive endpoint were 4.2 μg/L for H. azteca reproduction, 12 μg/L for C. dubia reproduction and C. dilutus emergence, and >28 μg/L for L. siliquoidea. Hyalella azteca was more sensitive to azoxystrobin compared with the other 3 species in the chronic exposures. No photo-enhanced toxicity was observed for either C. dubia or L. siliquoidea exposed to ultraviolet light in control water following azoxystrobin tests. The results of the present study indicate chronic effects of azoxystrobin on 3 of 4 invertebrates tested at environmentally relevant concentrations. The changes noted in biomass and reproduction have the potential to alter the rate of ecological processes driven by aquatic invertebrates. Environ Toxicol Chem 2017;36:2308-2315. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. [ABSTRACT FROM AUTHOR]

Fusicladium effusum is the cause of pecan scab, the most destructive disease of pecan in the south-eastern USA. The aim of the study was to determine how scab severity at different sample heights in tall trees (14-16 m) affected fruit and nut weight at those same heights. Three experiments were performed in 2010-2011 on trees of scab-susceptible cultivars (cvs. Desirable and Wichita) and either received fungicide using an air-blast sprayer or were non-treated controls. Samples for measures of fruit and nut weight were taken at 0-5.0, 5.0+-7.5, 7.5+-10.0, 10.0+-12.5 and 12.5+-15.0 m (and were assessed for scab severity). A general linear mixed model analysis showed main effects of sample height, fungicide treatment and sample height × fungicide treatment interactions in all experiments on fruit and nut weight and on disease severity. Control trees had significantly more severe disease on fruit lower in the canopy, while fungicide-treated trees either had similar disease severity at all heights or slightly more severe disease in the upper canopy. On control trees, where there was a linear relationships between fruit or nut weight and sample height, it was invariably positive ( R 2= .85-.94). On fungicide-treated trees, fruit or nut weight most often had a negative linear relationship with sample height ( R 2=.69-.89). When significant, in control and treated trees, there was invariably a negative linear relationship between fruit or nut weight and scab severity ( R 2=.66-.94). Gradients in fungicide coverage and scab severity impact fruit and nut weights that can have ramifications on yield for a tree as a whole. Understanding the distribution of scab in pecan and other tall tree canopies provides a basis for developing management strategies and fungicide application methods to uniformly minimize disease. [ABSTRACT FROM AUTHOR]

Stem canker on germinating potato sprouts is often caused by seed-borne inoculum of the fungus Rhizoctonia solani. However, high amounts of free-living plant-parasitic nematodes have been found in field patches of potato plants with stem canker. Fungicide treatment of the seed tubers can be used to avoid stem canker caused by seed-borne inoculum but it is unknown if nematodes can affect this. To investigate whether free-living plant-parasitic nematodes, the root-lesion nematode Pratylenchus penetrans or a combination of several plant-parasitic nematode genera in a full nematode community, may have a negative effect on the fungicide seed treatment, a pot experiment with seed tubers inoculated with R. solani, half of which were treated with fungicides, was performed. The seed-borne inoculum caused severe damage to the plants, while no fungal damages were observed on the fungicide treated plants. This shows that the nematodes did not affect the fungicide treatment. The probability of black scurf decreased in treatments with a full nematode community, which may be due to the action of fungal-feeding nematodes. [ABSTRACT FROM AUTHOR]

Six common fungicides, Dithane M45, Kocide 2000, Ridomil Gold Plus, Score, Equation Pro and Kemazed were tested for controlling the draceana leaf spot fungi. All the tested fungicides significantly decreased the in vitro growth of the tested dracaena leaf spot fungi. Percentage of inhibition on colony diameter ranged between 49.64% with Dithane M45 to 82.18% with Score which was followed by Kemazed (69.15%). However, inhibition of spore germination was the highest (72.8%) by Dithane M45, while inhibition of germ tube reached 89.91% with Kemazed. Meanwhile, in the in vivo tests, treatment with Kemazed decreased disease incidence of leaf spots on potted plants to 16.67% compared to 100% for the untreated inoculated control. On the other hand, the bacterial and fungal biocontrol agents tested proved to be effective against the dracaena leaf spot fungi. The in vitro assays conducted showed that the bacterial biocontrol agents namely, Stenotrophomonas maltophilia, Pseudomonas ultimum, P. fluorescens, P. putida, P. aeruginosa, Bacillus subtilis, B. megaterium, significantly decreased colony growth diameter (76.84-45.69%) of dracaena leaf spot fungi as well as spore germination (48.80-23.20%) and length of germ tube (88.77-65.65%) of the germinated spores compared to untreated control. Treatment with S. maltophilia showed the most consistent highest inhibition effect, followed by P. ultimum, B. subtilis, and B. megaterium, respectively. The in vivo tests of the most effective bacterial bioagents supported the in vitro results. Treatment with S. maltophilia showed the highest effect as it decreased disease incidence and disease index to 29.33% and 7.6%, respectively in comparison with 100% and 83.6% for the untreated inoculated control in the potted dracaena plants (cv. Bicolor). Meanwhile, the in vitro tests of the three Trichoderma spp., i.e. T. harzianum, T. hamatum and T. album showed significant inhibition effect on colony growth diameter of the tested dracaena leaf spot fungi in which T. harzianum showed the highest inhibition effect (75.02%), while T. album was most effective to inhibit spore germination (48%) and germ tube (90.21%) of the germinated spores. The in vivo tests of the fungal biocontrol agents supported the in vitro results. T. album (Bio-Zeid) showed the highest effect and decreased disease incidence and disease index on potted plants to 19.99% and 4.39%, respectively compared with 100% and 92.8% for the untreated inoculated control. [ABSTRACT FROM AUTHOR]

Septoria carvi is an important pathogen of caraway. With the increasing occurrence of septoriosis of caraway during warm and humid growing seasons, the possibility of limiting the growth and development of the fungus was investigated. In vitro studies included 2 preparations of natural origin, ie Biosept Active, Beta-chikol and 12 fungicides from different chemical groups, as well as one isolate K 1806 S. carvi, obtained from caraway. Tests were performed by poisoning the culture media. The percentage of inhibition of the growth of four- and eight-day-old fungus colonies on the medium with preparations in comparison to the control colonies was a measure of the toxic activity of the preparations. The effectiveness of Beta-chikol in limiting S. carvi colony growth was significantly higher than the efficiency of Biosept Active. All tested fungicides limited the growth of the fungus colony and their inhibitory effect increased with the concentration of the active ingredient in the medium. The most effective preparation in vitro was Signum 33 WG, belonging to the strobilurin compounds. In vivo studies investigated the effect of Beta-chikol, Biosept Active and Dithane NeoTec 75 WG on the health of caraway plants. The occurrence of septoriosis was determined basing on the presence of disease symptoms and the mycological analysis of diseased plants. A significant reduction of septoriosis symptoms on plants and plant colonization by the fungus was caused by Biosept Active and Dithane NeoTec 75WG. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Biociencias is the property of Revista Brasileira de Biociencias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The efficiency of some inducer resistance chemicals (IRCs) like bion, chitosan, humic acid and salicylic acid as well as the fungicides like Folu-Gold, Galben Copper, Previcure-N and Redomil Gold Mancozeb on management of sweet melon downy mildew, caused byPseudoperonospora cubensiswas evaluatedin vitroandin vivo. Also, the efficiency of the alternation between the sprayed two fungicides and IRCs on management of the disease and the produced fruit yield and its total soluble solids (TSS) under field conditions were assessed. The inhibitory effect of the IRCs and the tested fungicides on sporangial germination ofP. cubensisresulted in a significant reduction in the germinated sporangia. In addition, IRCs were less effective than the fungicides. Disease management revealed the same trend of thein vitroexperiment when they sprayed fungicides on sweet melon plants artificially inoculated with the sporangia of the causal fungus under greenhouse conditions. Furthermore, under field conditions, spraying sweet melon plants with the two tested fungicides was the most efficient in decreasing the disease and increasing fruit yield and its TSS, to somewhat, followed by the alternation between them and the tested IRCs. In addition, IRCs treatments showed the lowest efficiency in this regard. [ABSTRACT FROM AUTHOR]

A series of 5-substituted-2-furoyl diacylhydazide derivatives with aliphatic chain were designed and synthesized. Their structures were characterized by IR, ¹H NMR, elemental analysis, and X-ray single crystal diffraction. The anti-tumor bioassay revealed that some title compounds exhibited promising activity against the selected cancer cell lines, especially against the human promyelocytic leukemic cells (HL-60). Their fungicidal tests indicated that most of the title compounds showed significant anti-fungal activity. The preliminary structure-activity relationship showed that the aliphatic chain length and differences in the R² group had obvious effects on the anti-tumor and anti-fungal activities. The bioassay results demonstrated that the title compounds hold great promise as novel lead compounds for further drug discovery. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) continues to threaten the economic sustainability of many small grain producers in Manitoba by causing losses in grain yield and quality. In this 2-year study, four fungicides were tested on two spring wheat cultivars with different levels of resistance to FHB inoculated with 3ADON and 15ADON chemotypes ofFusarium graminearum. All fungicides (prothioconazole, tebuconazole, metconazole and prothioconazole+ tebuconazole) reduced FHB index, per centFusarium-damaged kernels (% FDK) and deoxynivalenol (DON) levels and increased yield compared with the non-sprayed control in the moderately resistant cultivar ‘Glenn’. In the highly susceptible cultivar ‘Roblin’, all fungicides reduced FHB index and increased yield compared with the non-sprayed control; however, inconsistent results were observed for FDK and DON. Differences were observed between the two chemotypes for all variables in both years except for FDK and yield in 2010. This study confirmed that host resistance plays an important role in host–pathogen–fungicide interaction. Therefore, the combined effect of growing moderately resistant cultivars with fungicide application can reduce damage caused by FHB even under high FHB severity. [ABSTRACT FROM AUTHOR]

Disease caused by Rhizoctonia solani Kühn infestations has become a growing problem for commercially important crops. Although this fungus is usually controlled through the application of chemicals, the heavy ecological and financial toll of the latter has prompted for research on biopesticides as a viable alternative. Trichoderma spp. is a well-known fungus often used for the biological control of crop pests, whose anti-fungal mechanisms include competition for the substrate, antibiosis and/or mycoparasitism. In the present work, we have used molecular techniques (sequencing of amplicons from the internal transcribed spacer of ribosomal DNA and the EF1A translation elongation factor) for the taxonomic identification of 13 Trichoderma spp. isolates in our collection, also evaluating their antibiotic effect on strains from three anastomosis groups of R. solani (AG-2.1, AG-5, AG-8) by the cellophane method. The sequences obtained from all isolates exhibited 100 % identity with deposited T. asperellum Samuels sequences in TrichoBLAST/GenBank, enabling their taxonomic assignment to this species. When analyzed by in vitro tests, over 70 % of the isolates exhibited a fungistatic effect towards R. solani, with the remaining strains exhibiting fungicidal activity; these results were later corroborated by technical efficacy tests under field conditions. Isolates 3, 13, 17, 75, 78, 85 and 90 were selected as potential biocontrol agents due to their high antibiotic activity and technical efficacy under field conditions. [ABSTRACT FROM AUTHOR]

The incidence of diseases caused by Rhizoctonia solani Kühn increases every year. Control of this disease is mainly done with the application of chemicals, more highly toxic. For this reason it is necessary to apply new control alternatives Trichoderma spp. is one of the biological control of this pathogen, for the friendly behavior and the different mechanisms of action, such as competition for the substrate, antibiosis and/or mycoparasitism. The present work had as objectives the molecular identification and the pathogenic evaluation, against R. solani isolates, of 13 isolates of the genus Trichoderma. For this, the antibiotic effect of Trichoderma asperellum on three R. solani anastomosis groups (AG-2.1, AG-5, AG-8) was evaluated by the method of cellophane. The characterization was carried out by sequencing the Internal Transcribed Spacer (ITS) of the rDNA region, as well as the EF1A translation elongation factor. Over 70 % of the strains tested showed fungistatic effect, whereas the rest showed fungicide effect. This was corroborated by the technical effectiveness under field conditions. After sequencing and comparison of data obtained with other sequences deposited in TrichoBLAST/GenBank, we found that all isolates showed 100 % identity with the T. asperellum Samuels species. Isolates 3, 13, 17, 75, 78, 85 and 90 were selected as promissory for their high antibiotic potential and technical efficacy in field conditions. [ABSTRACT FROM AUTHOR]

Specific scope This standard describes the conduct of trials for the efficacy evaluation of fungicides against foliar and ear diseases of cereals. Specific approval and amendment First approved in 1998-09. Revision approved in 2012-09. [ABSTRACT FROM AUTHOR]

The polyamine analogue, keto-putrescine, was shown to provide substantial control of infections by six economically important plant pathogens, with EC50 values ranging between 57 and 82 mg litre−1. However, keto-putrescine was relatively less effective in vitro against Phytophthora infestans, Pyricularia oryzae and Pyrenophora avenae, with EC50 values ranging from 145 to 340 mg litre−1. In contrast, the polyamine analogue N-acetylputrescine had to effect on in-vitro growth of P. avenae or P. oryzae or infection of barley seedlings with powdery mildew. When P. avenae was grown in the presence of keto-putrescine, there were small, insignificant reductions in ornithine decarboxylase activity, with more substantial, significant reductions in S-adenosylmethionine decarboxylase activity. These changes were accompanied by a 43% reduction in spermidine concentration and increased concentrations of spermine and cadaverine. [ABSTRACT FROM AUTHOR]

Nine diethyl chloroacetylanilidomethylphosphonates and ten diethyl α-(chloroacetylanilido)benzylphosphonates were prepared by N-chloroacetylation of the corresponding diethyl anilinomethyl- and anilinobenzylphosphonates. These were tested for antifungal activity against six phytopathogenic fungi. Most of the compounds showed moderate protective properties. No significant difference in activity was observed for compounds with an extra aryl ring substituent on the methylene group of the backbone. Compounds with electron-withdrawing substituents, especially chlorine, on the aniline site (R1) showed higher fungicidal activity than the other compounds with electron-donating groups as substituents. [ABSTRACT FROM AUTHOR]

One method of testing the effect of a fungicide on the growth of fungal mycelium in vitro involves implanting small discs of mycelium into agar plates impregnated with fungicide. Growth is measured as the increase in colony diameter with time, but it is possible for some growth to occur without a corresponding increase in colony diameter. Two empirical models, involving an upper threshhold dose, are considered for this situation. A 3-parameter model based on the exponential curve is found to provide a satisfactory fit to most of the sets of data considered. [ABSTRACT FROM PUBLISHER]

Leaf spot diseases have become a major concern in spinach production in the United States. Determining the causal agents of leaf spots on spinach, their prevalence and pathogenicity, and fungicide efficacy against these pathogens is vital for effective disease management. Spinach leaves with leaf spots were collected from Texas, California, Arizona, and South Carolina from 2016 to 2018, incubated in a moist chamber, and plated on potato dextrose and tryptic soy agar media. Fungal and bacterial colonies recovered were identified based on morphology and sequence analysis of the internal transcribed spacer rDNA and 16S rRNA, respectively. Two predominant genera were isolated: (i) Colletotrichum spp., which were identified to species based on sequences of both introns of the glutamate synthetase ( GS -I) and glyceraldehyde-3-phosphate dehydrogenase ( gapdh -I) genes; and (ii) Stemphylium spp., identified to species based on sequences of the gapdh and calmodulin ( cmdA ) genes. Anthracnose ( Colletotrichum spinaciae ) and Stemphylium leaf spot ( Stemphylium vesicarium and S. beticola ) were the predominant diseases. Additional fungi recovered at very limited frequencies that were also pathogenic to spinach included Colletotrichum coccodes , C. truncatum , Cercospora beticola , and Myrothecium verrucaria . All of the bacterial isolates were not pathogenic on spinach. Pathogenicity tests showed that C. spinaciae , S. vesicarium , and S. beticola caused significant leaf damage. The fungicides Bravo WeatherStik (chlorothalonil), Dithane F-45 (mancozeb), Cabrio (pyraclostrobin), and Merivon (fluxapyroxad and pyraclostrobin) were highly effective at reducing leaf spot severity caused by an isolate of each of C. spinaciae and S. vesicarium , when inoculated individually and in combination.