Use Of Fungicides Research Articles

Estimation of Yield Losses for Major Diseases (late leaf spot) in High Incidence Areas on Groundnut (Arachis hypogaea L.)

Late leaf spot (LLS, Phaeoisariopsis personata L.) is the major biotic constraint of groundnut (Arachis hypogaea L.) productivity in hot spot location in Maharashtra, India. The aim of this study was to determine the yield losses due to attack of diseases, with and without using the fungicide tebuconazole. Management of LLS through fungicides was evaluated with eight treatments in randomized block design with three replications during Kharif, 2021, 2022 and 2023 at Oilseed Research Station, Jalgaon, Maharashtra, India. Fungicidal spray impacted the development of Cercospora late leaf spot and reduced the disease intensity. No pod or haulm loss was observed when tebuconazole was sprayed at 25.9 EC (T4) at 50, 65, 80, and 95 DAS when compared to control treatment (T8), which showed losses of 35.95 % and 29.46 % respectively. It was followed by treatment T3 i.e. tebuconazole 25.9 % EC at 50, 65 and 80 DAS and treatment T5 i.e. Tebuconazole 25.9% EC at 65, 80 and 95 DAS. The pod and haulm yield loss in treatment T5 was 9.10% and 9.46%, respectively. The highest BCR was recorded by treatment T4 (4.67), followed by treatments T5 (4.51) and T3 (4.47), respectively. The results indicated that the use of fungicide significantly influenced disease management and, consequently, yield.

Revolutionizing Citrus Health: AI-Based Detection of Greening Disease and Nutrient Deficiencies in Sweet Orange

This paper explores the application of Artificial Intelligence (AI) techniques for detecting plant diseases, focusing on citrus greening disease and various foliar nutrient deficiencies in sweet orange. Agriculture faces numerous challenges from cultivation to harvesting, including significant yield losses due to disease infections and environmental hazards from excessive use of insecticides and fungicides. As the global population grows, the demand for food is surging, and traditional farming methods fall short in meeting this demand, often degrading soil health through intensive pesticide use. AI offers significant advantages over conventional techniques in disease detection. This study employs AI for visual detection of citrus greening disease and foliar nutrient deficiencies, achieving 87% accuracy on a test dataset of infected, nutrient-deficient, and healthy sweet orange leaves. Performance is evaluated using metrics such as Accuracy, Recall, Precision, and F1-Score. Specifically, Convolutional Neural Network (CNN) architectures, including Visual Geometry Group (VGG-16), are utilized for image-based detection and classification, demonstrating the potential of AI in enhancing plant health monitoring.

Efficacy of biocontrol agents against damping-off and Sclerotinia stem rot diseases and their role in eliciting defense in chickpea plants

BackgroundChickpea (Cicer arietinum L.) is the third most important pulse crop grown worldwide. Sclerotinia sclerotiorum causes damping-off and stem rot diseases, leading to significant economic losses in chickpea crop yield. Biological control has proved to be an effective alternative for managing plant diseases.ResultsThese pathogenic fungi were isolated from different governorates in Egypt and differed in terms of their pathogenicity on Giza 3 cv.-chickpea plants in vivo. S. sclerotiorum Sakha-S1 with accession No. (PQ558663) was the most aggressive isolate. Trichoderma atroviride was the most effective fungal bioagent in vitro since recorded the highest S. sclerotiorum growth decrease, followed by T. hamatum and T. harzianum; meanwhile, Serratia sp. was the least effective isolate. In greenhouse conditions, Topsin M-70® emerged as the most successful treatment for reducing disease prevalence. Combinations of microbial bioagents specifically all four (T. atroviride, Pseudomonas fluorescens, Bacillus polymyxa, and Serratia sp.) and a combination of three (P. fluorescens, B. polymyxa, and Serratia sp.) followed in effectiveness. Serratia sp. applied alone proved to be the least effective treatment. The same results were obtained in a two-year field study (2020–2021 and 2021–2022) and assessed the impact of various treatments on chickpea disease, growth, and yield components. Interestingly, all the microbial bioagents substantially enhanced chickpea growth parameters, including plant height, number of branches per plant, number of capsules per plant, number of seeds per plant, seed weight per plant, average weight of 100 seeds, and overall chickpea yield. The role of these microbial bioagents in the defense of oxidation enzymes (Peroxidase, polyphenol oxidase, and catalase) associated with defense-related genes (ABR18, PRP, and PR-4) which shown notable variations in gene expression levels of defense-related genes due to treated with various microbial bioagents after 14 days from application. All three genes were up-regulated in combinations including (P. fluorescens + Serratia sp.), (T. atroviride + P. fluorescens), and (T. atroviride + Serratia sp.), demonstrating a collaborative impact on defense gene expression.ConclusionThe study investigated the effectiveness of microbial bioagents against chickpea stem rot disease, their role in the defense of oxidation enzymes and defense-related genes, and their impact on growth and yield components. It will focus on producing commercial biofungicides to minimize the use of fungicides.

Synthesis, antifungal activity, and molecular simulation study of nootkatone-based thiazole-hydrazone compounds as novel succinate dehydrogenase inhibitor.

Plant diseases cause huge losses in agriculture worldwide every year, but the prolonged use of current commercial fungicides has led to the development of resistance in plant pathogenic fungi. Therefore, there is an urgent need to develop new, efficient, and green fungicides. Twenty-three nootkatone-based thiazole-hydrazone compounds were designed, synthesized, and characterized by Fourier-transform infrared (FTIR), proton (1H) nuclear magnetic resonance (NMR), carbon-13 (13C) NMR, and high-resolution mass spectrometry (HRMS). The antifungal activities results showed that all the target compounds displayed certain antifungal activity against eight tested fungi. Among them, target compounds 3a (88.7%), 3b (92.5%), 3d (88.7%), 3f (84.9%), 3j (88.7%), and 3l (92.5%) were comparable or superior to the positive control boscalid (88.7%) in their inhibitory activities against Physalospora piricola. Meanwhile, target compound 3l had half maximal effective concentration (EC50) values of 18.0172, 18.8236, 16.5914, 18.5044, and 16.5660 μg/mL against Fusarium oxysporum f. sp. cucumerinum, Alternaria solani, Gibberella zeae, Bipolaris maydis, and Colleterichum orbicalare, respectively, exhibiting outstanding and broad-spectrum fungicidal activity. Moreover, a three-dimensional quantitative structure-activity relationship (3D-QSAR) study was carried out to investigate the relationship between the molecular structures of target compounds 3a-3w and their antifungal activity. Furthermore, the target compound 3l [half maximal inhibitory concentration (IC50) = 4.936 μmol/L] showed significantly better inhibitory activity against succinate dehydrogenase (SDH) than boscalid (IC50 = 6.631 μmol/L). The possible binding mode between target compound 3l and homology-modeling built SDH, was also explored by molecular docking. Target compound 3l deserved further study as the promising candidate for the development of novel SDH inhibitor. © 2025 Society of Chemical Industry.

Integrated approach for managing groundnut stem rot caused by Sclerotium rolfsii Sacc.

Groundnut (Arachis hypogaea L.), often referred to as the King of oil seeds, is a vital oil seed crop cultivated globally. However, its productivity is hampered by numerous abiotic and biotic stresses, with biotic stresses predominantly due to fungal and bacterial diseases. Among these, soil-borne fungal pathogens cause significant yield losses. Specifically, stem rot disease, caused by Sclerotium rolfsii Sacc., poses a substantial threat, leading to yield losses of up to 80%. This pathogen forms sclerotia, a resilient resting structure that can survive in the soil for many years and germinate under favorable environmental conditions. The persistence of sclerotia and the pathogen's broad host range make managing this disease particularly challenging through a single method. Effective management of stem rot disease necessitates an integrated disease management (IDM) approach, which combines cultural, chemical, and biological strategies. Cultural practices such as crop rotation, deep ploughing, and moisture regulation help to reduce inoculum levels in the soil. Chemical control involves the use of fungicides to reduce the pathogen load in the soil and protect the plants during vulnerable growth stages. Biological control employs antagonistic microorganisms that can inhibit the growth and activity of S. rolfsii. By integrating these diverse strategies, it is possible to effectively manage stem rot disease in groundnut, thereby enhancing productivity and sustainability in groundnut cultivation.

Antioomycete Nanoformulation for Biocontrol of English Walnut Crown and Root Rot Caused by Phytophthora cinnamomi.

In Chile and worldwide, walnut (Juglans regia L.) production faces significant losses due to crown and root rot caused by the phytopathogen Phytophthora cinnamomi. Currently, control methods have proven insufficient or unfavorable for the environment, increasing the need for sustainable alternatives. This research evaluates nanoemulsions based on extracts of medicinal plants endemic to Chile to control P. cinnamomi in walnut crops. The methodology included an in vitro test to determine the effective inhibitory concentrations of three nanoemulsions (N80, N90, and N100) on the mycelial growth of the phytopathogen, a test on walnut plants under controlled conditions, and two field tests using concentrations between 300 and 500 ppm. The in vitro results showed that the nanoemulsions could inhibit 90% of mycelial growth at 80 to 100 ppm concentrations. In the field, the N90 nanoemulsion at 500 ppm significantly reduced disease symptoms preventively and post-inoculation, compared with the control. This research is the first to study the use of nanoemulsions from native Chilean plants to control P. cinnamomi, showing potential to reduce the use of synthetic fungicides, contributing to safer and more ecological phytosanitary management.

Temporal dynamics of airborne fungi in Swedish forest nurseries.

In Sweden, reforestation of managed forests relies predominantly on planting nursery-produced tree seedlings. However, the intense production using containerized cultivation systems (e.g., high seedling density, irrigation from above, regular fertilization) creates favorable conditions for fungal infections. Despite the harmful role of diseases in forest nurseries, the origin and dispersal factors of fungal pathogens remain largely unknown. A better understanding of the airborne spread of pathogens could improve the prediction of fungal infection, ultimately optimizing preventative methods and decreasing the use of fungicides. This study investigated the temporal dynamics of airborne fungi in forest nurseries, with a focus on fungal pathogens. Airborne fungi were monitored in four Swedish forest nurseries over two growing seasons using spore traps and high-throughput sequencing. Fungal pathogens were identified using bioinformatics and quantified with quantitative PCR. Results showed strong temporal shifts of airborne fungal diversity and community composition following the growing seasons. The airborne spread included high abundances of important fungal pathogens (e.g., Cladosporium sp., Botrytis cinerea, Alternaria sp., Sydowia polyspora, and Melampsora populnea) with individual temporal and spatial variations. In general, the deposited spore loads of nursery pathogens correlated positively with increased temperature and negatively with higher precipitation. This was expressed the strongest for Cladosporium sp., Alternaria sp., and M. populnea, which suggests a higher availability of fungal inoculum in warm and dry periods. This study highlights the influence of seasonality on the temporal dynamics of economically important fungal pathogens in Swedish forest nurseries, which should be considered in the development of a local decision support system.IMPORTANCEFungal diseases in forest nurseries have significant environmental and economic impacts on the tree seedling production. This study highlights the role of seasonality in the airborne spread of fungal pathogens in Swedish forest nurseries. By analyzing airborne fungal spores using advanced sequencing and monitoring techniques, key fungal pathogens and their dispersal patterns over two growing seasons were identified. The findings indicate that warmer, drier periods may increase the spread of fungal pathogens, emphasizing the need for targeted preventative measures. Understanding these temporal dynamics can help optimize the use of fungicides in forest nurseries, thereby promoting more sustainable and environmentally friendly management practices. This research provides valuable insights for improving disease management in forest nurseries, ultimately supporting sustainable tree seedling production.

Characteristics of VOCs Emissions from Pesticide Use Sources Based on Pesticide Dosage Forms Analysis： A Case Study of Beijing

To analyze the emission characteristics of VOCs from pesticide use sources in Beijing, the distribution of commonly used pesticides and dosage forms in Beijing was obtained through on-site research, and the VOC content of pesticides in different dosage forms was examined using laboratory testing methods. The emission factors of pesticide VOCs for localized dosage forms in Beijing were established, an inventory of pesticide use source VOCs was compiled, and the spatial and temporal distribution characteristics of pesticide use source VOCs were analyzed. The results indicated that ① Pesticide dosage forms were the main factors affecting the emission of VOCs from pesticides, and when accounting for VOC emissions from pesticide sources, it is necessary to know the types of pesticides and active ingredients in the target area and obtain information on pesticide dosage forms simultaneously. ② The localized emission factors for different dosage forms of pesticides were, in descending order, emulsifiable concentrate （839 g·kg-1）, soluble concentrate （715 g·kg-1）, emulsion in water （659 g·kg-1）, micro-emulsion （371 g·kg-1）, suspension concentrate （121 g·kg-1）, wettable powder （34 g·kg-1）, water dispersible granule （30 g·kg-1）, and aqueous solution （17 g·kg-1）. ③ In 2020, pesticide use and VOC emissions from pesticide use sources in Beijing were 2 990 t and 757 t. Among them, pesticide use of fungicides was the largest, accounting for 54.3% of the total, but its VOC emissions only accounted for 6.5%. Insecticides accounted for 34.8% of the pesticide use, and their VOC emissions were 84.1%. Among the different crop types, fruit trees had higher emissions of VOCs, with mixed fruits being the highest, accounting for 48.1%. ④ In terms of spatial distribution, the areas with higher emissions of VOCs were the ecological conservation development area （70.5%） and the new urban development area （24.4%）, with the Pinggu district having the highest emissions of VOCs, followed by the Miyun district and the Fangshan district, which accounted for 30.7%, 11.8%, and 8.9% of the total, respectively. Crops that contributed more to the ecological conservation development area were fruit trees, maize, potatoes, beans, etc.； crops that contributed more to the new urban development area were vegetables, wheat, and melons. In terms of time distribution, summer and spring were the peak periods for VOC emissions from pesticide use sources, accounting for 45.2% and 33.8% of the total, respectively.

Spray-Induced Gene Silencing (SIGS) as a Tool for the Management of Pine Pitch Canker Forest Disease.

Global change is exacerbating the prevalence of plant diseases caused by pathogenic fungi in forests worldwide. The conventional use of chemical fungicides, which is commonplace in agricultural settings, is not sanctioned for application in forest ecosystems, so novel control strategies are imperative. Spray-induced gene silencing (SIGS) is a promising approach that can modulate the expression of target genes in eukaryotes in response to double-stranded RNA (dsRNA) present in the environment that triggers the RNA interference mechanism. SIGS exhibited notable success in reducing virulence when deployed against some crop fungal pathogens, such as Fusarium graminearum, Botrytis cinerea, and Sclerotinia sclerotiorum, among others. However, there is a conspicuous dearth of studies evaluating the applicability of SIGS for managing forest pathogens. This research aimed to determine whether SIGS could be used to control F. circinatum, a widely impactful forest pathogen that causes pine pitch canker disease. Through a bacterial synthesis, we produced dsRNA molecules to target fungal essential genes involved in vesicle trafficking (Vps51, DCTN1, and SAC1), signal transduction (Pp2a, Sit4, Ppg1, and Tap42), and cell wall biogenesis (Chs1, Chs2, Chs3b, and Gls1) metabolic pathways. We confirmed that F. circinatum is able to uptake externally applied dsRNA, triggering an inhibition of the pathogen's virulence. Furthermore, this study pioneers the demonstration that recurrent applications of dsRNAs in SIGS are more effective in protecting plants than single applications. Therefore, SIGS emerges as an effective and sustainable approach for managing plant pathogens, showcasing its efficacy in controlling a globally significant forest pathogen subject to quarantine measures.

From Natural Hosts to Agricultural Threats: The Evolutionary Journey of Phytopathogenic Fungi.

Since the domestication of plants, pathogenic fungi have consistently threatened crop production, evolving genetically to develop increased virulence under various selection pressures. Understanding their evolutionary trends is crucial for predicting and designing control measures against future disease outbreaks. This paper reviews the evolution of fungal pathogens from natural habitats to agricultural settings, focusing on eight significant phytopathogens: Pyricularia oryzae, Botrytis cinerea, Puccinia spp., Fusarium graminearum, F. oxysporum, Blumeria graminis, Zymoseptoria tritici, and Colletotrichum spp. Also, we explore the mechanism used to understand evolutionary trends in these fungi. The studied pathogens have evolved in agroecosystems through either (1) introduction from elsewhere; or (2) local origins involving co-evolution with host plants, host shifts, or genetic variations within existing strains. Genetic variation, generated via sexual recombination and various asexual mechanisms, often drives pathogen evolution. While sexual recombination is rare and mainly occurs at the center of origin of the pathogen, asexual mechanisms such as mutations, parasexual recombination, horizontal gene or chromosome transfer, and chromosomal structural variations are predominant. Farming practices like mono-cropping resistant cultivars and prolonged use of fungicides with the same mode of action can drive the emergence of new pathotypes. Furthermore, host range does not necessarily impact pathogen adaptation and evolution. Although halting pathogen evolution is impractical, its pace can be slowed by managing selective pressures, optimizing farming practices, and enforcing quarantine regulations. The study of pathogen evolution has been transformed by advancements in molecular biology, genomics, and bioinformatics, utilizing methods like next-generation sequencing, comparative genomics, transcriptomics and population genomics. However, continuous research remains essential to monitor how pathogens evolve over time and to develop proactive strategies that mitigate their impact on agriculture.

A conserved fungal Knr4/Smi1 protein is crucial for maintaining cell wall stress tolerance and host plant pathogenesis.

Filamentous plant pathogenic fungi pose significant threats to global food security, particularly through diseases like Fusarium Head Blight (FHB) and Septoria Tritici Blotch (STB) which affects cereals. With mounting challenges in fungal control and increasing restrictions on fungicide use due to environmental concerns, there is an urgent need for innovative control strategies. Here, we present a comprehensive analysis of the stage-specific infection process of Fusarium graminearum in wheat spikes by generating a dual weighted gene co-expression network (WGCN). Notably, the network contained a mycotoxin-enriched fungal module (F12) that exhibited a significant correlation with a detoxification gene-enriched wheat module (W12). This correlation in gene expression was validated through quantitative PCR. By examining a fungal module with genes highly expressed during early symptomless infection that was correlated to a wheat module enriched in oxidative stress genes, we identified a gene encoding FgKnr4, a protein containing a Knr4/Smi1 disordered domain. Through comprehensive analysis, we confirmed the pivotal role of FgKnr4 in various biological processes, including oxidative stress tolerance, cell cycle stress tolerance, morphogenesis, growth, and pathogenicity. Further studies confirmed the observed phenotypes are partially due to the involvement of FgKnr4 in regulating the fungal cell wall integrity pathway by modulating the phosphorylation of the MAP-kinase MGV1. Orthologues of the FgKnr4 gene are widespread across the fungal kingdom but are absent in other Eukaryotes, suggesting the protein has potential as a promising intervention target. Encouragingly, the restricted growth and highly reduced virulence phenotypes observed for ΔFgknr4 were replicated upon deletion of the orthologous gene in the wheat fungal pathogen Zymoseptoria tritici. Overall, this study demonstrates the utility of an integrated network-level analytical approach to pinpoint genes of high interest to pathogenesis and disease control.

Impact of the use of azole fungicides, other than as human medicines, on the development of azole-resistant Aspergillus spp.

The use of azoles in the European Union and European Economic Area (EU/EEA) other than as human medicines has raised concerns about emergence and spread of azole-resistant Aspergillus species. EU agencies, with the support of JRC, reviewed the evidence and provided conclusions and recommendations on this topic. Although incomplete, data from 2010 to 2021 showed that around 120,000 tonnes of azoles were sold in EU/EEA for uses other than as human medicines. The majority are used as plant protection products (119,000 tonnes), with a stable temporal trend. Evidence supported a link between environmental azole exposure and cross-resistance selection to medical azoles in Aspergillus species (primarily shown for A. fumigatus). Prevalence of azole-resistant A. fumigatus in human A. fumigatus infections ranges from 0.7% to 63.6% among different disease presentations and geographic regions; mortality rates range from 36% to 100% for invasive aspergillosis (IA). It was concluded that azole usage outside the human domain is likely or very likely to contribute to selection of azole-resistant A. fumigatus isolates that could cause severe disease like IA. Environmental hotspots for resistance selection were identified, including stockpiling of agricultural waste and their possible use as soil amendment/fertiliser for certain agricultural crops (for plant protection products) and freshly cut wood (for biocides). Recommendations were formulated on measures to prevent and control selection of azole resistance in A. fumigatus, including implementation of good agricultural/horticultural practices, proper agricultural and wood waste storage and management, and on approval of new azole fungicides or renewal of existing fungicides. Recommendations on topics to be covered by studies provided when submitting applications for the approval of azole fungicides were listed. For the evaluation of such studies within the approval procedure, a preliminary framework for risk assessment was developed and should be further refined. Data gaps and uncertainties were identified, alongside with respective recommendations to address them.

Uji Potensi Isolat Rhizobakteri Menekan Pertumbuhan Jamur Antraknosa Cabai Merah (Capsicum annum L.) secara In Vitro

The main problem in red chili production is the attack of pests and diseases, particularly anthracnose caused by the fungus Colletotrichum spp., which can reduce yields by up to 60% if not controlled. Control methods typically involve the use of fungicides; however, excessive use can lead to pathogen resistance and negative environmental impacts. Therefore, there is a need for more environmentally friendly control alternatives, such as the utilization of biocontrol agents like rhizobacteria. This study aims to evaluate the inhibitory capacity and potential of rhizobacteria in suppressing the growth of Colletotrichum sp. fungi. In the first phase, 20 rhizobacterial isolates were tested, and 5 isolates were selected for further testing in the second screening phase. The research employed a non-factorial Completely Randomized Design, consisting of 6 rhizobacterial treatments with 5 replications, resulting in a total of 30 experimental units. The best inhibitory capacity was observed in rhizobacterial isolate RB 5 (2.44%) and RB 2 (2.41%). All rhizobacterial isolates exhibited variations in colony characteristics, color, and staining results. Additionally, all tested isolates showed potential for phosphate (P) solubilization, indicated by the formation of clear zones around the rhizobacterial suspensions. The highest catalase enzyme production was observed in isolates RB 3 and RB 5. While the rhizobacterial isolate RB 3 demonstrated pathogenicity, as evidenced by the softening of potato tissue after being scratched with the isolate, it still maintained a good inhibitory effect against the growth of Colletotrichum sp.

Evaluating the Efficacy of Fungicides for Controlling Late Blight in Tomatoes Induced by Phytophthora infestans

Tomato (Solanum lycopersicum L.), is an important crop in tropical and subtropical regions, but it is highly susceptible to biotic stresses, particularly late blight caused by Phytophthora infestans. This fungus disease can lead to sudden outbreaks, resulting in severe crop losses. Chemical control remains a vital strategy for managing such outbreak. This study evaluated the effectiveness of 20 different fungicides, sprayed at recommended doses, for controlling late blight tomato and improving tomato production. A susceptible tomato variety, Nagina, was grown under randomized complete block design (RCBD) in vivo. Based on the percentage of disease infections produced on tomato plants and statistical analysis results, the results found that Chlorostrobin (13.62%), Cabrio Top (14.91%), Curzate M (15.38%), Ridomil Gold (16.77%), Jalva (17.13%), Nanok (19.2%), and Antracol (19.34%) were the most effective fungicides against P. İnfestans. Other fungicides such as Co-pride (21.1%), Flumax (21.54%), Alliette (23.81%), Score (24.35%), Success 40 WSP (25.13%), and Melody Due (28.82%) also exhibited effective results. However, fungicides like Rally (32.23%), Cytrol (34.28%), Thrill (37.46%), Evito (37.52%), Shincar (43.63%), Topas (45.83%), and Tilt (48.59%) were less effective in controlling the disease. These findings highlight the importance of using Chlorostrobin, Cabrio Top, Curzate M, Ridomil Gold, Jalva, Nanok, and Antracol are highly effective fungicides to combat late blight. This targeted approach ensures that fungicides are applied when they are most effective at preventing disease outbreaks, reducing overall fungicides use and costs.

A Zinc Polyphenolic Compound Increases Maize Resistance Against Infection by Bipolaris maydis.

Maize leaf blight (MLB), caused by the fungus Bipolaris maydis, is an important disease affecting maize production. In order to minimize the use of fungicides in agriculture, nutrient-based resistance inducers may become a promising alternative to manage MLB. The goal of this study was to investigate the potential of Semia® (zinc (20%) complexed with a plant-derived pool of polyphenols (10%)) to hamper the infection of maize leaves by B. maydis by analyzing their photosynthetic performance and carbohydrate and antioxidative metabolism, as well as the expression of defense-related genes. Plants were sprayed with water (control) or Semia® (referred to as induced resistance (IR) stimulus hereafter) and not inoculated or inoculated with B. maydis. The mycelial growth and conidium germination were significantly reduced by the IR stimulus in vitro. The MLB severity was significantly reduced by 76% for IR-stimulus-sprayed plants compared to plants from the control treatment. For infected and IR-stimulus-sprayed plants, the glucose, fructose, sucrose, and starch concentrations were significantly higher compared to inoculated plants from the control treatment. The activity levels of superoxide dismutase, ascorbate peroxidase, catalase, and glutathione reductase were significantly higher for the IR-stimulus-sprayed plants compared to plants from the control treatment. Less impairment on the photosynthetic apparatus (higher values for leaf gas exchange (rates of net CO2 assimilation, stomatal conductance to water vapor, and transpiration) and chlorophyll a fluorescence (variable-to-maximum Chl a fluorescence ratio, photochemical yield, and yield for dissipation by down-regulation) parameters)) along with a preserved pool of chlorophyll a+b and carotenoids were noticed for infected and IR-stimulus-sprayed plants compared to infected plants from the control treatment. The defense-related genes IGL, CHS02, PR1, PAL3, CHI, and GLU were strongly up-regulated in the leaves of IR-stimulus-sprayed and infected plants compared to infected plants from the control treatment. These findings highlight the potential of using this IR stimulus for MLB management.

Review Artikel : Potensi Actinomycetes Sebagai Antijamur Pada Suatu Tanaman

Plant damage caused by phytopathogenic fungi is a serious issue in agriculture. Conventional approaches using synthetic pesticides have proven effective in controlling plant diseases but pose environmental and health problems and increase pathogen resistance to chemicals. Consequently, recent research focuses on developing environmentally friendly and effective biocontrol agents. Numerous studies highlight the potential use of microbial-based biocontrol agents, such as bacteria and fungi from the genera Streptomyces, Bacillus, and Pseudomonas, in protecting plants from diseases. Specifically, actinomycetes, a subgroup of bacteria that produce bioactive secondary metabolites, have been successfully utilized as biocontrol agents against phytopathogenic fungi and bacteria. This study employs a literature review method, searching through Google Scholar and PubMed with keywords such as Antifungal Activity, Actinomycetes, Phytopathogens, and Plant Biocontrol Agents. The results indicate that actinomycetes are widely used as antifungal agents in agriculture, possessing various antagonistic mechanisms against phytopathogenic fungi through secondary metabolites, host resistance induction, siderophores, and lytic enzymes. This review article examines the various mechanisms of actinomycetes as biocontrol agents in agriculture and their antagonistic roles against phytopathogenic fungi, presenting an alternative to the future use of synthetic fungicides

Resistant wheat cultivars and fungicide applied at stem elongation or mid-anthesis are effective stripe rust control strategies in Saskatchewan

Stripe rust, caused by Puccinia striiformis f. sp. tritici, has been observed frequently on wheat since 2010 in Saskatchewan. The deployment of resistant cultivars and the use of fungicides are common control measures for this disease. The effectiveness of fungicide application at various timings on wheat cultivars varying in resistance to the disease at two seeding dates was determined in central Saskatchewan from 2012 to 2016. Under high disease pressure, a single fungicide application at mid-anthesis growth stage of wheat seeded mid-May decreased disease severity of the susceptible cultivar ‘AC Barrie’ from 87% (unsprayed control) to 26% and protected yield by 59%. The response was somewhat less dramatic for the moderately resistant cultivar ‘CDC Imagine’; stripe rust severity was reduced from 54% to 14%, and yield protected by 32%. Similar effects of fungicide application were observed for thousand kernel weight, test weight and protein content. Furthermore, at a later seeding date (early June), fungicide application at stem elongation reduced stripe rust severity on the susceptible cultivar ‘AC Barrie’ from 87% to 51% and protected yield by 53%. Fungicide applied at the mid-anthesis stage had the same positive effect, reducing symptoms from 87% to 54% and increasing yield by 46%. Fungicide application had no detectable effect on stripe rust severity of the resistant cultivar ‘Lillian’ at any growth stage of either seeding date experiment. The study demonstrated that, under the conditions that prevail in Saskatchewan, a single fungicide application at stem elongation or mid-anthesis, depending on seeding date, can reduce disease severity, protect yield and improve grain quality in wheat cultivars susceptible and moderately resistant to stripe rust.

Sensitivity determination and resistance mechanism of Sclerotium rolfsii to difenoconazole.

Peanut stem rot, caused by Sclerotium rolfsii, has become increasingly prevalent in China, leading to significant yield losses in peanut production. To effectively manage peanut stem rot, we assessed the potential application of difenoconazole against peanut stem rot. Difenoconazole has a good inhibitory effect on the mycelial growth of S. rolfsii, with half maximal effective concentration (EC50) values ranging from 0.10 to 1.58 μg/mL and an average of 0.33 ± 0.02 μg/mL. Nonetheless, a small percentage of wild-type isolates exhibiting low resistance to difenoconazole were identified in the field. The primary reason for S. rolfsii resistance to difenoconazole was found to be attributed to the overexpression of CYP51. In addition, a small number of resistant isolates also exhibited multidrug resistance through the overexpression of efflux pump genes atrB and atrD. Pot experiments revealed that difenoconazole demonstrated superior protective efficacy against peanut stem rot, with mist spray treatment exhibiting better control efficacy compared to root drench treatment. Specifically, at a concentration of 100 μg/mL, the protective efficacy of difenoconazole mist spray against peanut stem rot reached 65.24%, which was statistically similar to that of tebuconazole. Furthermore, no significant correlation was observed between sensitivity to difenoconazole and mefentrifluconazole, benzovindiflupyr, boscalid, thifluzamide, carboxin, or picoxystrobin. To delay the emergence of resistant populations, we recommend early-stage application of difenoconazole via spraying for peanut stem rot management, alongside the judicious use of fungicides with no cross-resistance like thifluzamide and boscalid for optimal control. © 2024 Society of Chemical Industry.

Exploring the potentiality of botanicals and phyllosphere microbiome for the management of anthracnose disease in Black gram (Vigna mungo L. Hepper)

Black gram (Vigna mungo L. Hepper) is the third most important pulse crop, and its yield is reduced due to many diseases. Among them, anthracnose is one of the devasting global fungal diseases which cause severe damage. Use of fungicide is highly effective in controlling this disease, but continuous use of fungicides is unsafe for environment, and it causes fungicidal resistance. To overcome these problems, effect of plant extracts viz., Anisomeles malabarica, Azadirachta indica leaf extracts, phyllosphere antagonist Bacillus amyloliquifaciens, and essential oils viz., peppermint oil and lemon grass oil were evaluated against black gram anthracnose disease caused by Colletotrichum lindimuthianum under pot culture. Among the different treatments tested, plants sprayed with standard chemical viz., Carbendazim @ 0.2 percent recorded the least percent disease index (PDI) of 13.39 followed by A. malabarica leaf extract (10%) treatments, which recorded a PDI of 16.62, whereas plants treated with B. amyloliquifaciens, lemongrass oil and peppermint oil recorded a PDI of 20.91, 21.23 and 24.0, respectively, compared to the inoculated control (77.33 PDI). The induction of defense enzymes viz., phenol, peroxidase (PO), polyphenol oxidase (PPO) was recorded more (21.25 µg of catechol/g of leaf tissue, 3.82 changes in absorbance/min/g leaf tissue, 3.32 changes in absorbance/min/g leaf tissue, respectively) in the plants sprayed with A. malabarica. GC-MS analysis of hexane and ethanol extract of A. malabarica showed the presence of 26 phytocompounds. Among them, phenol 2,4- bis (1,1- dimethylethyl) phosphite from ethanol extract was a predominant compound (100%). Formulation and standardization of dosage for phenol 2,4- bis (1,1- dimethylethyl) phosphite compound will be useful for managing the disease effectively.

Comparative effectiveness of some novel fungicides and different biocontrol agents against two Colletotrichum musaeisolates under laboratory condition

Colletotrichum musae, is aggressive and devastating threat and causing huge losses in banana production globally. The use of various fungicides and as well as biocontrol agents can help to manage the crop. However, five different fungicides, namely., Antracol, Defeater plus, Ridomil gold, Kocide, and Topsin M at five different concentrations viz., 10 ppm, 100 ppm, 200 ppm, 500 ppm, and 1000 ppm were used to check the growth inhibition of the two isolates (CM02 and CM11) of C. musae by food poison technique. The topsin M fungicide at all concentrations (10-1000 ppm) was highly effective, which yielded 72-98% inhibition, followed by Ridomil gold 1000 ppm caused 82.11% and 79% inhibition of both isolates. Ridomil gold at 500 ppm causes 75.13% and 69.44% mycelial growth inhibition of CM02 and CM11. In comparison, Kocide at 1000 ppm caused more than 60% inhibition of both strains. However, we observed that, as the concentration decreased the mycelial growth of the pathogen increased. Furthermore, during the present investigation, three biocontrol agents, viz., Trichoderma harzianum, Trichoderma polysporum and Paecilomyces variotii were used for their antifungal activity against (CM02 and CM11) by dual assay test. T. harzianum proved highly effective biocontrol agents and cause (18.88% and 20.11%) mycelial inhibition of both strains, followed by T. polysporum (13.33% and 15%) and P. variotii (9.11% and 8.75%) on 3rd, 4th and 7th day of inoculation by dual assay test. In conclusion, among all tested fungicides, Topsin M was found highly effective against both strains of Colletotrichum musae. Therefore, biological control especially with Trichoderma species are promising method to control this pathogen quickly. Both isolates of C. musae showed high sensitivity against Trichoderma species on the third and fourth day of inoculation.