Chemical Fungicides Research Articles

Green synthesis of silver nanoparticles for antifungal activity against tomato fusarium wilt caused by Fusariumoxysporum

Fusarium wilt caused by Fusarium oxysporum f. sp. radicis-lycopersici is one of the most important diseases in tomatoes, resulting in severe yield loss and mycotoxin infection in food and feed. The management of Fusarium wilt is based heavily on chemical fungicides, but these chemicals have many environmental concerns. Silver nanoparticles (AgNPs) are gaining importance as emerging resistance-free alternatives of chemical fungicides. In this study, AgNPs were synthesized using the aqueous leaf extract of Viola odorata as a green approach. The antifungal activity of these biosynthesised AgNPs was evaluated in vitro against F. oxysporum using the agar well diffusion method. AgNPs were also evaluated against tomato Fusarium wilt diseases using the foliar spray method in the greenhouse. The characterization of AgNPs revealed that AgNPs were of spherical shape, crystalline in nature, and had an average size of 18 nm. In the antifungal assay, 60 mg/l AgNPs strongly inhibited the growth of F. oxysporum with a growth zone of 18 ± 0.89 mm compared to fungicide (23 ± 1.20 mm) and AgNO3 (52 ± 2.33 mm). Similarly, 60 mg/l of AgNPs when sprayed on tomato plants in the greenhouse showed a survival rate of about 80% with no observable phytotoxic effect. This study provides a first baseline to control Fusarium wilt in tomato using biosynthesised AgNPs without affecting the health of crops.

Novel Essential Oil-Based Thiosemicarbazone Compounds as Potential Fungicides in Controlling Postharvest Diseases of Citrus Fruit.

To develop novel fungicides for controlling postharvest fungal diseases in citrus fruits, 12 essential oil (EO)-based thiosemicarbazones compounds, termed hydrazine-carbothioamide, were prepared according to the condensation method. In vitro assays showed that compound 13j exhibited the strongest antifungal activity (minimum inhibitory concentration [MIC] = minimum fungicidal concentration [MFC] = 0.0125 mg/mL) against Penicillium digitatum. An in vivo study revealed that 5 × MFC of compound 13j can effectively mitigate the green mold incidence of citrus fruit inoculated with P. digitatum, as well as fruit rot during natural storage, at a level comparable to that of the chemical fungicide prochloraz. Throughout this process, fruit quality was maintained. The hemolysis assay showed that these thiosemicarbazone compounds have good biocompatibility and that their safety is comparable to that of prochloraz. The antifungal activity of compound 13j was attributed to membrane damage, as confirmed using scanning electron microscopy (SEM), Calcofluor white (CFW) staining, propidium iodide (PI) staining, Fourier transform-infrared (FT-IR) spectroscopy, optical density (OD)260, and relative conductivity assays. Collectively, our results indicate that compound 13j can be used as an antifungal agent to control the postharvest decay of citrus fruits.

Unveiling the intricacies of the rice-Rhizoctonia pathosystem: a comprehensive review of host-pathogen interactions, molecular mechanisms, and strategies for sustainable management

Sheath blight disease in rice, induced by the necrotrophic basidiomycetes Rhizoctonia solani, has emerged as a significant menace to global rice cultivation, especially with the widespread adoption of high-yielding varieties. The pathogen’s capacity to endure unfavorable conditions and its wide host range contribute to the increased challenge for management. The occurrence of sheath blight in rice is intensified when high-yielding semi-dwarf cultivars are employed, coupled with dense planting and the application of substantial amounts of nitrogenous fertilizers. Managing this pathogen is a formidable challenge due to its broad host range, substantial genetic variability, and the absence of satisfactory levels of natural resistance in the existing rice germplasm. Due to the absence of complete resistance sources, the predominant approach for managing sheath blight has been through chemical control methods. It is imperative to explore solutions to combat this pathogen, in order to reduce rice yield losses and safeguard global food security. Developing genetic resistance provides an alternative to the use of potentially harmful chemical fungicides. This review crucially delivers efforts to enhance the understanding of the host–pathogen relationship, which involves identification of gene loci/markers associated with resistance responses, modification of host genome through transgenic approaches, examining the wide host range, epidemiology and its managemental approaches. Recent advancements and current research on the R. solani–rice pathosystem, along with a gap analysis, are presented.

Assessment of Okra Powdery Mildew (Erysiphe Cichoracearum DC) by Using Bio-agents and Chemical Fungicides

The present study aimed to assess okra powdery mildew (Erysiphe Cichoracearum DC) by using bio-agents and chemical fungicides. Okra (Abelmoschus esculentus (L.) Moench occupies a prominent place in the horticultural wealth and economy of the country. Powdery mildew disease on okra (Abelmoschus esculentus (L.) Moench incited by fungus, Erysiphe cichoracearum is a limiting factor in the successful cultivation in Bundelkhand region of Uttar Pradesh. Studies were carried out to find out disease management strategies against okra powdery mildew using bioagents and chemical fungicides. Disease incidence declined after first, second and third sprays. The fungicide Hexaconazole (Contaf 5% EC) @ 0.1%, showed significantly lowest disease incidence (19.53 %) with maximum (68.40 %) disease control. On the basis of effectiveness in controlling the powdery mildew disease of okra the most effective fungicides recorded in the order of merit were Carbendazim (Bavistin 50WP) @0.1%, Propiconazole (Tilt 25EC) @0.1%, Trichoderma viride (3 %), Sulphur (Sulfex 80% WP) @ 0.3%, Pseudomonas flouresens (4 %) and Trichoderma harizum (4 %).

Appraisal of antifungal potential of chemicals and plant extracts against brown leaf spot of soybean caused by Septoria glycine

Soybean is a legume crop originating in China. Its nutritional value, characterized by high-quality protein and unsaturated fats, makes it an excellent cholesterol-free diet option. Brown leaf spot of soybean, caused by Septoria glycine, is one of the most devastating diseases, resulting in significant yield losses. This study aimed to evaluate the effectiveness of new chemical fungicides (Topsin-M, Recado, Evito, Polyram-DF, and Curzate-M) at concentrations of 50, 100, and 150 ppm, and phyto-extracts (neem, clove, eucalyptus, ficus, and datura) at concentrations of 3, 5, and 7% against S. glycine under in vitro conditions. The most effective treatments from the in vitro tests were further investigated under greenhouse conditions using a completely randomized design with three replications per treatment. The results indicated that, among the fungicides, Topsin-M showed the lowest mycelial growth (3.5, 2.73, and 2.34 mm) at concentrations of 50, 100, and 150 ppm, respectively. Among the phyto-extracts, clove demonstrated the most effective results, with the least fungal growth (3.95 mm) at 7% concentration. Under greenhouse conditions, the best results were achieved with a combination of Topsin-M and clove, resulting in the lowest disease incidence (10.27%), followed by Topsin-M (17.65%) and clove (26.76%). This study suggests that new chemical fungicides and phyto-extracts can be effectively used as part of an integrated management strategy against brown leaf spot of soybean.

Effectiveness of some novel fungicides against the sheath blight pathogen Rhizoctonia solani in rice under in vitro and in vivo conditions

Sheath blight of rice, caused by Rhizoctonia solani, is one of the most aggressive and damaging diseases in rice cultivation, leading to significant crop losses. Consequently, chemical fungicides are the most effective method to inhibit R. solani infection and control this disease. In the present study, R. solani isolate was obtained from infected rice plants, and its pathogenicity was confirmed using Koch’s postulates on 20-day-old rice seedlings at three different inoculum levels. The lowest percent disease index and disease incidence were recorded with the 1 ml pathogen inoculum suspension, while the 2 ml and 3 ml suspensions resulted in 100% disease incidence, significantly affecting plant parameters. Furthermore, five different fungicides, Duphetar Plus, Evito, Nativo, Ridomil Gold, and Shincar, were evaluated at three concentrations (10, 100, and 1000 ppm) against R. solani using poisoned food method. The results revealed that two fungicides, Shincar and Nativo, resulted in maximum mycelial growth inhibition of R. solani, whereas the other fungicides failed to inhibit the mycelial growth of the pathogen at all concentrations. Shincar and Nativo were further tested in a greenhouse setting to control pathogen infection in rice plants. These fungicides showed excellent results, reducing R. solani infection and minimizing disease incidence in treated rice plants compared to the control. The highest root length, shoot length, and plant weight were observed with Shincar, followed by Nativo. It is suggested that the use of these fungicides may reduce sheath blight disease incidence, effectively control pathogen infection, and improve plant growth parameters in field conditions.

Harnessing the antagonistic potential and unraveling the bioactive compounds of Streptomyces sp. isolate WAB2 to protect watermelon crop from Colletotrichum orbiculare

ABSTRACT Watermelon (Citrullus lanatus Thumb) is a significant vegetable crop globally and is prone to anthracnose disease caused by Colletotrichum spp. The use of chemical fungicides for managing crop diseases has adverse impacts on the environment and human health. Therefore, it is important to use biocontrol agents for disease management. In this study, streptomycetes were assessed as a potential biocontrol agent against anthracnose pathogen, Colletotrichum orbiculare WEC2. The potent Streptomyces sp. isolate WAB2 was isolated from healthy watermelon plants and showed remarkable antifungal efficacy against C. orbiculare WEC2. Rigorous assays confirmed its performance against C. orbiculare WEC2. Bioactive compounds produced by Streptomyces sp. isolate WAB2 were identified using Gas Chromatography–Mass Spectrometry (GC–MS). An SEM study indicated the parasitic action of Streptomyces sp. isolate WAB2 against the pathogen. The formulated talc-based product of Streptomyces sp. isolate WAB2 was effective when applied as a seed treatment + foliar spray against C. orbiculare WEC2 under pot culture conditions. These treatments reduced the disease incidence (31.81%) and exhibited a higher disease reduction (52.56%), compared to the untreated control. Therefore, treatment with talc-based Streptomyces sp. isolate WAB2 is a sustainable solution for anthracnose disease management, and it facilitates eco-friendly crop protection practices against the disease in watermelon. RESEARCH HIGHLIGHTS Isolated streptomycete strains from healthy watermelon plants and screened for its efficacy against the pathogen, Colletotrichum orbiculare WEC2. Streptomyces sp. isolate WAB2 showed significant antifungal activity against the pathogen. Bio-active compounds produced by Streptomyces sp. isolate WAB2 was identified by Gas Chromatography–Mass Spectrometry (GC–MS). Using scanning electron microscopy (SEM), the parasitic activity of Streptomyces sp. isolate WAB2 against the pathogen was detected. Developed a talc-based formulation of Streptomyces sp. isolate WAB2 and tested it as a seed treatment plus foliar spray, effectively reducing the disease incidence.

Relative efficiency of some chemical fungicides used for the control of rice blast (Magnaporthe oryzae B. Cauch) in Jigawa State, Nigeria

Relative efficiency of some chemical fungicides used for the control of rice blast (Magnaporthe oryzae B. Cauch) in Jigawa State, Nigeria

Application of Asteraceae biomass and biofertilizers to improve potato crop health by controlling black scurf disease.

Potato (Solanum tuberosum L.) cultivation in Pakistan faces challenges, with black scurf disease caused by Rhizoctonia solani Kühn being a significant concern. Conventional methods like chemical fungicides partially control it, but an effective solution is lacking. This study explores the potential of biofertilizers and soil amendments from Asteraceae weed biomass to manage the disease. Two potato varieties, Karoda and Sante, were chosen, and two biofertilizers, Fertibio and Feng Shou, were tested alone or with Xanthium strumarium biomass. Disease pressure was highest in the positive control, with significant reduction by chemical fungicide. X. strumarium biomass also decreased disease incidence significantly. Fertibio showed better efficacy than Feng Shou. Physiological and biochemical attributes of plants improved with biofertilizer and biomass application. Tuber weight, photosynthetic pigments, total protein content, and antioxidant enzymes (CAT, POX, and PPO) were positively correlated. Combined application of Fertibio and S. marianum biomass effectively managed black scurf disease. These eco-friendly alternatives could enhance disease management and yield. Future research should explore their cost-effectiveness, commercialization, and safety.

Enhancing Resistance to Cercospora Leaf Spot in Mung Bean (Vigna radiata L.) through Bradyrhizobium sp. DOA9 Priming: Molecular Insights and Bio-Priming Potential.

Mung bean (Vigna radiata L.), a vital legume in Asia with significant nutritional benefits, is highly susceptible to Cercospora leaf spot (CLS) caused by Cercospora canescens, leading to significant yield losses. As an alternative to chemical fungicides, bio-priming with rhizobacteria can enhance plant resistance. This study explores the potential of Bradyrhizobium sp. strain DOA9 to augment resistance in mung bean against CLS via root priming. The results reveal that short (3 days) and double (17 and 3 days) priming with DOA9 before fungal infection considerably reduces lesion size on infected leaves by activating defense-related genes, including Pti1, Pti6, EDS1, NDR1, PR-1, PR-2, Prx, and CHS, or by suppressing the inhibition of PR-5 and enhancing peroxidase (POD) activity in leaves. Interestingly, the Type 3 secretion system (T3SS) of DOA9 may play a role in establishing resistance in V. radiata CN72. These findings suggest that DOA9 primes V. radiata CN72's defense mechanisms, offering an effective bio-priming strategy to alleviate CLS. Hence, our insights propose the potential use of DOA9 as a bio-priming agent to manage CLS in V. radiata CN72, providing a sustainable alternative to chemical fungicide applications.

Biocontrol of citrus fungal pathogens by lipopeptides produced by Bacillus velezensis TZ01.

Citrus diseases caused by fungal pathogens drastically decreased the yield and quality of citrus fruits, leading to huge economic losses. Given the threats of chemical pesticides on the environment and human health, biocontrol agents have received considerable attention worldwide as ecofriendly and sustainable alternative to chemical fungicides. In the present study, we isolated a Bacillus velezensis strain TZ01 with potent antagonistic effect against three citrus pathogenic fungi: Diaporthe citri, Colletotrichum gloeosporioides and Alternaria alternata. The culture supernatant of this strain exhibited remarkable antifungal activity on potato dextrose agar plates and detached leaves of five citrus varieties. Treatment with TZ01 culture supernatant obviously affected the hyphal morphology and caused nucleic acid leakage. The crude lipopeptides (LPs) extracted from the culture supernatant were found as the major active ingredients, and could maintain the activity under a wide range of temperature and pH and ultraviolet radiation. Furthermore, the type of LPs, produced in vitro, were explored. Whole-genome sequencing of TZ01 revealed secondary metabolite gene clusters encoding synthetases for non-ribosomal peptides and polyketide production, and gene clusters responsible for the synthesis of three important LPs (surfactin, iturin, and fengycin) were identified in the genome. The liquid chromatography-mass spectrometry analysis confirmed the presence of various homologs of surfactin A, bacillomycin D, and fengycin A in the extracted LPs. Taken together, these results contribute to the possible biocontrol mechanisms of B. velezensis strain TZ01, as well as providing a promising new candidate strain as a biological control agent for controlling citrus fungal pathogens.

Effect of Different Chemical Inducers on Mycelial Growth of Neoscytali̇di̇um di̇mi̇di̇atum

Neoscytalidium dimidiatum has become one of the most aggressive fungal pathogen that cause economical damage to plants with changing climatic conditions. Pathogen causes disease symptoms including dieback, canker, blight, root rot, leaf spot, and fruit rot at a wide range of plant species and significant yield losses and damages. Some studies have been conducted on the efficiency of different chemical fungicides against the pathogen, but no effective control method has been found. Also, comprehensive studies on different control methods were needed due to the disadvantages in the use of chemical fungicides. The aim of the study was to evaluate the effects of chitosan (1, 1.5, 2 mg/ml), MeJA (0.01, 0.1, 1 mM) and BTH (0.01, 0.1, 1 mM) on mycelial growth of N. dimidiatum. The results showed statistically significant differences among the inhibition rates of chemical inducers against N. dimidiatum, but also among different doses of chemical inducers as compared to control. Chitosan at 2 mg/ml concentration was the most effective with the inhibition rate of 45.2%, followed by 1.5 mg/ml and 1 mg/ml doses of chitosan, that inhibited mycelial growth at the rates of 44.6 and 37.9%, respectively. BTH was the second most effective treatment after chitosan with the inhibition rate of 18.9% at 1 mM dose, while MeJA was sufficiently ineffective in inhibiting the mycelium growth of N. dimidiatum at the concentrations tested. The results indicated that chitosan could be an alternative to fungicides due to its high level of effectiveness and non-toxicity.

Phenazines are involved in the antagonism of a novel subspecies of Pseudomonas chlororaphis strain S1Bt23 against Pythium ultimum

Long-term use of chemical fungicides to control plant diseases caused by fungi and oomycetes has led to pathogen resistance and negative impacts on public health and environment. There is a global search for eco-friendly methods and antagonistic bacteria are emerging as alternatives. We isolated a potent antagonistic bacterial strain (S1Bt23) from woodland soil in Québec, Canada. Taxonomic characterization by 16S rRNA, multi-locus sequence analysis, pairwise whole-genome comparisons, phylogenomics and phenotypic data identified strain S1Bt23 as a novel subspecies within Pseudomonas chlororaphis. In dual culture studies, strain S1Bt23 exhibited potent mycelial growth inhibition (60.2–66.7%) against Pythium ultimum. Furthermore, strain S1Bt23 was able to significantly bioprotect potato tuber slices from the development of necrosis inducible by P. ultimum. Annotations of the whole genome sequence of S1Bt23 revealed the presence of an arsenal of secondary metabolites including the complete phenazine biosynthetic cluster (phzABCDEFG). Thin-layer (TLC) and high-performance liquid (HPLC) chromatographic analyses of S1Bt23 extracts confirmed the production of phenazines, potent antifungal compounds. CRISPR/Cas9-mediated deletion of phzB (S1Bt23ΔphzB) or phzF (S1Bt23ΔphzF) gene abrogated phenazine production based on TLC and HPLC analyses. Also, S1Bt23ΔphzB and S1Bt23ΔphzF mutants lost antagonistic activity and bioprotection ability of potato tubers against P. ultimum. This demonstrated that phenazines are involved in the antagonistic activity of S1Bt23 against P. ultimum. Finally, based on genotypic and phenotypic data, we taxonomically conclude that S1Bt23 represents a novel subspecies for which the name Pseudomonas chlororaphis subsp. phenazini is proposed.

Metabolite profiling and molecular characterization of NBAIR BSWG1: A potential strain of Bacillus subtilis against Fusarium oxysporium f. sp. udum

To address the fungal wilt of pigeon pea caused by Fusarium oxysporium f. sp. udum, farmers currently rely on chemical fungicides, despite their harmful effects. However, there is a growing need for safer alternatives like green pesticides. Bacterial biocontrol agents and their derivatives serve as potential green pesticides in the management of plant pathogens. In the present study, we aimed to identify indigenous Bacillus subtilis strains effective against F. oxysporium f. sp. udum. We used PCR and MALDI-TOF analysis to identify the active components responsible for the efficiency of efficient strain. Biochemical studies of cell-free extracts extracted from B. subtilis strains demonstrated the highest biosurfactant activity in NBAIR BSWG1, with an oil displacement of 2 cm and an emulsification index of 60 %. Molecular characterization confirmed the presence of surfactin, fengycin, and iturin coding genes in the B. subtilis strains, among them, NBAIR BSWG1 showed the highest number of lipopeptide-producing genes. Meanwhile, NBAIR BSWG1 showed inhibition of 79.84 % against F. oxysporium f. sp. udum using cell-free extract. Further metabolite profiling of NBAIR BSWG1 using MALDI-TOF analysis further confirmed surfactin, fengycin, and iturin in the purified cell-free extract of NBAIR BSWG1. Two peaks with m/z of 923.77 and 1149.92 were identified as novel lipopeptide compounds which need further characterization. The present study identified NBAIR BSWG1 as an efficient bacterial strain for the inhibition of F. oxysporium f. sp. udum and its antifungal properties are mainly due to the production of cyclic lipopeptides.

Antifungal Efficacy of Kappaphycus alvarezii and Other Macro-algae against Alternaria solani Induced Early Blight in Tomato (Solanum lycopersicum L.)

Aims: To evaluate the antifungal activity of various seaweed extracts against A. solani under in vitro conditions. Methodology: The pathogen A.solani was isolated and its pathogenicity confirmed through inoculation on tomato plants. Molecular characterization was performed using PCR amplification and sequencing of the Internal Transcribed Spacer (ITS) region. Seaweed species, including Sargassum wightii, Kappaphycus alvarezii, Gracilaria edulis, Caulerpa racemosa, and Ulva lactuca, were collected, processed, and extracted using various solvents. The antifungal activity of these seaweed extracts was assessed using the Poisoned Food Technique, measuring the inhibition of A. solani growth. Results: Among the seaweed extracts tested, Kappaphycus alvarezii demonstrated the highest antifungal activity, with a maximum mycelial growth inhibition of 76% at a 5% concentration. Sargassum wightii also showed significant antifungal properties, with a 71.10% reduction in mycelial growth. Conclusion: The study reveals the promising potential of seaweed extracts, particularly Kappaphycus alvarezii and Sargassum wightii, as natural antifungal agents against A. solani. These findings suggest that seaweed-based bio-stimulants could serve as effective, eco-friendly alternatives to chemical fungicides in managing early blight disease in tomatoes are in tomato crops and highlights the potential of seaweed extracts as a natural antifungal agent.

The effectiveness of using the laboratory samples based on bacteria of the genus Streptomyces on peas in the conditions of the Volga-Vyatka region

Data on productivity, fungal diseases and the quality of seed peas grown on sod-podzolic medium-clay soil in 2021–2023 using pre-sowing seed treatment separately and in combination with plant vegetation treatment with experimental preparations based on local strains of the genus Streptomyces (A4 and 8A1-3) are presented. The comparison drugs were the chemical fungicide Pioneer, KS and the biological drug Pseudobacterin-2, J. The assessment of the biological effectiveness (BE) of the drugs was carried out on cultivars of peas of various morphotypes bred by the FARC North-East: ‘Falensky yubileiny’, ‘Falensky usaty’, ‘Falensky kormovoy’. The biological effectiveness of all tested preparations in protecting peas from root rot and ascochitosis was determined by the weather conditions of the year of research. In 2021, a significant decrease in the development of root rot compared with the control (38.4 %) was facilitated by seed treatment with a preparation based on S. antimycoticus 8A1-3 strain (29.0 %). A significant reduction in the development of pea root rot in 2022 was achieved by seed treatment with the chemical fungicide Pioneer (by 9.1 %), the reference bio-drug Pseudobacterin-2 (by 9.9 %) and the test strain S. antimycoticus 8Al-3 (by 7.1 %). In protecting peas from ascochitosis in 2022, the strain Streptomyces A4 (BE 72.7 %) proved itself as a Pioneer chemical fungicide (BE 72.7 %), and the strain Streptomyces 8A1-3 (BE 84.1 %) significantly surpassed them in effectiveness. The effect of drugs on the yield of peas in the years of research (HTC = 0.77–0.83 with an average long-term HTC = 1.4) was estimated as insignificant. Treatment with both experimental and commercial preparations of seeds and vegetative plants did not adversely affect the grain size and the content of crude protein in it. The ‘Falensky usaty’ was distinguished among the studied cultivars by large seeds: the mass of 1000 grains was 258.8±18.5 g. The ‘Falensky kormovoy’ and the ‘Falensky jubileiny’ cultivars proved to be medium-seeded ones (174.7±23.1 and 147.9±37.1 g, respectively). The content of crude protein in grain was negatively affected by the development of root rot on peas (correlation coefficient r =-0.77). The maximum crude protein content was recorded during the joint treatment of seeds and plants with a preparation based on S. castalarensis A4 (24.0±2.6 %) in the ‘Falensky jubileiny’ cultivar, with Pseudobacterin-2 (23.1±2.0 %) in the ‘Falensky kormovoy’ cultivar, with a preparation based on S. antimycoticus 8A1-3 (21.1±1.7 %) in the ‘Falensky usaty’ cultivar.

Biocontrol of citrus melanose Diaporthe citri by Bacillus subtilis M23

Citrus melanose, caused by Diaporthe citri, is one of the most prevalent and important fungal diseases of citrus crops globally. However, the overuse of chemical fungicides for disease control has an adverse impact on citrus production. In contrast, biological control agents (BCAs) are environmentally friendly and have become essential tools for plant disease control. In the present study, Bacillus subtilis M23, a strain isolated from healthy citrus leaves, significantly suppressed the mycelial growth of D. citri, the causal agent of citrus melanose, in vitro. The fermentation broth of B. subtilis M23 also exhibited good antifungal activity against D. citri on citrus plants in greenhouse and field experiments. Lipopeptides (LPs) produced by M23 exhibited excellent antifungal activity against D. citri, with a 50 % effective concentration (EC50) of approximately 1.00 and 0.28 μg/mL for inhibition of mycelial growth and conidial germination, respectively. LP biosynthesis genes were identified in the M23 genome using a PCR assay. Notably, LP extracts significantly reduced the formation of pycnidia and ATP biosynthesis in D. citri. Comparative transcriptome analysis revealed significant differences in the expression of genes associated with fungal vacuole, oxidoreductase activity and endopeptidase activity in D. citri treated with B. subtilis M23. Both RNA-seq and RT-qPCR analysis provided similar results on the expression of selected genes. Collectively, our data provided convincing data supporting the biocontrol potential of B. subtilis M23 for the management of citrus melanose.

Bioefficacy of Novel Chemical Fungicides for Management of Mango Powdery Mildew

Mango (Mangifera indica L.), the king of the fruits, is considered the most important fruit among millions of people worldwide, particularly in India. Among all diseases, powdery mildew caused by Oidium mangiferae is one of the most common, wide spread and serious diseases throughout the world causing significant yield losses. In this study experiments were conducted for two seasons by using new fungicides to control the disease along with some old ones. Among all fungicides tested Tebuconazole 50% + Trifloxystrobin 25% WG reduced the disease severity significantly. In both the seasons (pooled) Tebuconazole 50% + Trifloxystrobin 25% WG worked significantly by reducing the disease with PDI of 3.33 per cent and per cent disease reduction over control of 87.51.

Antagonistic Mechanism Analysis of Bacillus velezensis JLU-1, a Biocontrol Agent of Rice Pathogen Magnaporthe oryzae.

Magnaporthe oryzae, the causal agent of rice blast, is a fungal disease pathogen. Bacillus spp. have emerged as the most promising biological control agent alternative to chemical fungicides. In this study, the bacterial strain JLU-1 with significant antagonistic activity isolated from the rhizosphere soil of rice was identified as Bacillus velezensis through whole-genome sequencing, average nucleotide identity analysis, and 16S rRNA gene sequencing. Twelve gene clusters for secondary metabolite synthesis were identified in JLU-1. Furthermore, 3 secondary metabolites were identified in JLU-1, and the antagonistic effect of secondary metabolites against fungal pathogens was confirmed. Exposure to JLU-1 reduced the virulence of M. oryzae, and JLU-1 has the ability to induce the reactive oxygen species production of rice and improve the salt tolerance of rice. All of these results indicated that JLU-1 and its secondary metabolites have the promising potential to be developed into a biocontrol agent to control fungal diseases.

Apple scab: resistance to chemical fungicides

The review highlights the situation with the development of resistance to various systemic fungicides in Venturia inaequalis around the world and in Russia, with an assessment of the prospects for their further use. Information is provided on all fungicides used in Russia against apple scab, their effectiveness at a given time, and a description of each chemical class. Data on the mechanisms of resistance to chemicals in the pathogen, including at the molecular level, are presented. The problem of the development of resistance in V. inaequalis and possible ways of its solution at the present level of scientific knowledge are discussed.