Chemical Fungicides Research Articles

Biological control of Aspergillus flavus infection and growth promotion of peanut seedlings by Lactiplantibacillus plantarum and Levilactobacillus brevis

BackgroundAspergillus spp. infection might induce negative effects on peanut seeds, including decreased germination rates and suppressed seedling vigor. Furthermore, A. flavus can secret aflatoxin, regarding food safety and human health. The prolonged use of fungicides for treating mold infections has raised concerns regarding the emergence of fungicide-resistant strains, environmental pollution, and adverse effects on human health. The usage of lactic acid bacteria, including Lactiplantibacillus plantarum and Levilactobacillus brevis for the management of plant diseases, has garnered increasing attention in recent years as a viable alternative to chemical-based therapies. This study aimed to investigate the efficacy of LABs in pre-treating peanut seeds as a biological solution against A. flavus infection before cultivation.ResultsLactiplantibacillus plantarum and Levilactobacillus brevis have demonstrated the ability to suppress A. flavus in vitro. In the in vivo investigation, pre-treatment of peanut seeds with cell-free supernatant derived from L. plantarum (LP-CFS) and L. brevis (LB-CFS) significantly reduced A. flavus infection levels. The conidial count decreased from 8.63 log conidia/g in the untreated group to 5.35 log conidia/g with LP-CFS treatment and 4.59 log conidia/g with LB-CFS treatment. Additionally, A. flavus infection reduced the germination rate of peanut seeds to only 20.4% compared to 63.6% in the control group. In comparison, pre-treatment with LP-CFS and LB-CFS increased the germination rate to 75.6% and 76.8%, respectively, and further improved the vigor index in A. flavus-infected peanut seeds.ConclusionThe present findings indicated that bioactive compounds derived from L. plantarum and L. brevis emerge as promising candidates for treating peanut seeds, effectively protecting them against A. flavus infection. Moreover, these compounds facilitate the growth of seedlings, which could be a potential alternative to chemical fungicides, and contribute to sustainable agricultural development.

Identification and evaluation of an endophytic antagonistic yeast for the control of gray mold (Botrytis cinerea) in apple and mechanisms of action

Gray mold, caused by Botrytis cinerea, is a prevalent postharvest disease of apple that limits their shelf life, resulting in significant economic losses. The use of antagonistic microorganisms has been shown to be an effective approach for managing postharvest diseases of fruit. In the present study, an endophytic yeast strain PGY-2 was isolated from apples and evaluated for its biocontrol efficacy against gray mold and its mechanisms of action. Results indicated that strain PGY-2, identified as Bullera alba, reduced the occurrence of gray mold on apples and significantly inhibited lesion development in pathogen-inoculated wounds. Gray mold control increased with the use of increasing concentrations of PGY-2, with the best disease control observed at 108 cells/mL. Notably, Bullera alba PGY-2 did not inhibit the growth of Botrytis cinerea in vitro indicating that the yeast antagonist did not produce antimicrobial compounds. The rapid colonization and stable population of PGY-2 in apple wounds at 4 °C and 25 °C confirmed its ability to compete with pathogens for nutrients and space. PGY-2 also had a strong ability to form a biofilm and enhanced the activity of multiple defense-related enzymes (POD, PPO, APX, SOD, PAL) in host tissues. Our study is the first time to report the use of Bullera alba PGY-2 as a biocontrol agent for postharvest diseases of apple and provide evidence that Bullera alba PGY-2 represents an endophytic antagonistic yeast with promising biocontrol potential and alternative to the use of synthetic, chemical fungicides for the control of postharvest gray mold in apples.

Biological Control of Root Rot of Strawberry by Bacillus amyloliquefaciens Strains CMS5 and CMR12.

Strawberry root rot caused by Fusarium solani is one of the main diseases of strawberries and significantly impacts the yield and quality of strawberry fruit. Biological control is becoming an alternative method for the control of plant diseases to replace or decrease the application of traditional chemical fungicides. To obtain antagonistic bacteria with a high biocontrol effect on strawberry root rot, over 72 rhizosphere bacteria were isolated from the strawberry rhizosphere soil and screened for their antifungal activity against F. solani by dual culture assay. Among them, strains CMS5 and CMR12 showed the strongest inhibitory activity against F. solani (inhibition rate 57.78% and 65.93%, respectively) and exhibited broad-spectrum antifungal activity. According to the phylogenetic tree based on 16S rDNA and gyrB genes, CMS5 and CMR12 were identified as Bacillus amyloliquefaciens. Lipopeptide genes involved in surfactin, iturin, and fengycin biosynthesis were detected in the DNA genomes of CMS5 and CMR12 by PCR amplification. The genes related to the three major lipopeptide metabolites existed in the DNA genome of strains CMS5 and CMR12, and the lipopeptides could inhibit the mycelial growth of F. solani and resulted in distorted hyphae. The inhibitory rates of lipopeptides of CMS5 and CMR12 on the spore germination of F. solani were 61.00% and 42.67%, respectively. The plant-growth-promoting (PGP) traits in vitro screening showed that CMS5 and CMR12 have the ability to fix nitrogen and secreted indoleacetic acid (IAA). In the potting test, the control efficiency of CMS5, CMR12 and CMS5+CMR12 against strawberry root rot were 65.3%, 67.94% and 88.00%, respectively. Furthermore, CMS5 and CMR12 enhanced the resistance of strawberry to F. solani by increasing the activities of defense enzymes MDA, CAT and SOD. Moreover, CMS5 and CMR12 significantly promoted the growth of strawberry seedlings such as root length, seedling length and seedling fresh weight. This study revealed that B. amyloliquefaciens CMS5 and CMR12 have high potential to be used as biocontrol agents to control strawberry root rot.

Inhibition mechanism of Rhizoctonia solani by pectin-coated iron metal-organic framework nanoparticles and evidence of an induced defense response in rice

Nanocrop protectants have attracted much attention as sustainable platforms for controlling pests and diseases and improving crop nutrition. Here, we reported the fungicidal activity and disease inhibition potential of pectin-coated metal-iron organic framework nanoparticles (Fe-MOF-PT NPs) against rice stripe blight (RSB). An in vitro bacterial inhibition assay showed that Fe-MOF-PT NPs (80 mg/L) significantly inhibited mycelial growth and nucleus formation. The Fe-MOF-PT NPs adsorbed to the surface of mycelia and induced toxicity by disrupting cell membranes, mitochondria, and DNA. The results of a nontargeted metabolomics analysis showed that the metabolites of amino acids and their metabolites, heterocyclic compounds, fatty acids, and nucleotides and their metabolites were significantly downregulated after treatment with 80 mg/L NPs. The difference in metabolite abundance between the CK and Fe-MOF-PT NPs (80 mg/L) treatment groups was mainly related to nucleotide metabolism, pyrimidine metabolism, purine metabolism, fatty acid metabolism, and amino acid metabolism. The results of the greenhouse experiment showed that Fe-MOF-PT NPs improved rice resistance to R. solani by inhibiting mycelial invasion, enhancing antioxidant enzyme activities, activating the jasmonic acid signaling pathway, and enhancing photosynthesis. These findings indicate the great potential of Fe-MOF-PT NPs as a new RSB disease management strategy and provide new insights into plant fungal disease management.

Fungicides, bio-controllers and resistance inducers affect bioactive compounds and oxidative metabolism in bell pepper plants inoculated with Phytophthora capsici

ABSTRACT The rational use of chemical fungicides in chilli pepper (Capsicum annuum L.) for controlling Phytophthora capsici Leo. should include molecules that promote induced systemic resistance in the plant. The study objective was to assess how the application of fungicides, bio-controllers and resistance inducers affects bioactive compounds production and oxidative metabolism in pepper plants when inoculated with P. capsici zoospores. Statistical analyses show significant differences in total flavonoids, total phenols and salicylic acid concentrations in plants treated with Trichoderma harzianum, Acibenzolar-S-Methyl (ASM) and phosphonic acid. In addition, the application of ASM and Bacillus subtilis showed the highest values of antioxidant capacity. On the other hand, ASM application favoured increases in superoxide dismutase and phenyl ammonium lyase activity with values of 4.42 ± 0.016 (units · min−1 · g−1) and 3.90 ± 0.22 U · g−1, respectively. However, hydrogen peroxide production was similar to that of phosphonic acid treatments. Similarly, plants treated with B. subtilis and Metalaxyl-M showed increases in peroxidase enzyme activity with values ranging from 2.86 ± 0.05 to 4.52 ± 0.02 (μmol · [mg protein]−1 · min−1). Likewise, phosphonic acid-treated plants exhibited high catalase enzyme activity with values ranging from 2.38 ± 0.032 μmol H2O2 · min−1 · g−1 to 4.30 ± 0.024 μmol H2O2 · min−1 · g−1. The complementary use of products with biological and resistance-inducing functions could help to mitigate the environmental impacts that occur due to the use of chemical fungicides for controlling P. capsici on chilli pepper.

Antagonist Test of Trichoderma sp and Gliocladium sp Againts Fungal Pathogens That Cause Diseases on Tomato Plant

Tomatoes (Solanum lycopersicum) are one of the widely cultivated crops consumed by people worldwide, including Indonesia. Tomato farming often faces various challenges that result in reduced tomato productivity. One of the challenges is the presence of diseases that affect tomatoes, leading to crop failure for farmers. Some important diseases that commonly affect tomato plants include Fusarium wilt and anthracnose. Most farmer use chemical fungicides to control the diseases. These methods have greater negative impacts on both plants and the surrounding environment. One alternative control technique that can be used is the use of biological agents with antagonistic properties, such as Trichoderma sp. and Gliocladium sp. This research aims to assess antagonistic abilities of endophytic fungi Trichoderma sp. and Gliocladium sp. againts the pathogens responsible for suppresing the growth of these disease-causing phatogens in tomato plants. in the Laboratory of Plant Pest and Disease Science, OECF Building, Faculty of Agriculture, Universitas Mulawarman. The experiment was designed using a completely randomized single-factor design with four treatments and five replications. The data obtained were analyzed using Analysis of Variance and the least significant difference test at a 5% significance level. The research results indicate that the antagonistic tests of Trichoderma sp. and Gliocladium sp. in vitro significantly differ againts the pathogenic fungi Fusarium sp. and Colletotrichum sp. Furthermore, it was found that the antagonistic fungus Gliocladium sp. is the best fungus capable of suppressing the growth of important pathogenic fungi in tomato plants.Keyword: Gliocladium sp., Trichoderma sp., Fusarium sp., Colletotrichum sp. and Tomato (Solanum lycopersicum)

Combination of Bacillus tequilensis with difenoconazole to control pear black spot and the related synergistic mechanism.

Pear black spot (PBS) is caused by Alternaria alternata and causes severe damage worldwide. It is particularly important to screen for synergistic fungicide combinations to address issues associated with the low efficacy of biocontrol agents, high dosage requirements and poor sustained effectiveness of chemical fungicides. In vitro and in vivo studies were performed to determine the efficacy of a treatment for this important disease. Additionally, transcriptomic and metabolomic analyses were performed to determine the main molecular and biochemical mechanisms involved in the interaction. Bacillus tequilensis 2_2a has a significant synergistic effect with difenoconazole, causing hyphal entanglement and spore lysis and inhibiting the formation of PBS lesions in vitro. In the field, the control effect of the combination was greater than 95%. The pathways associated with the synergistic effect on the mycelia of A. alternata were divided into two main types: one included glycolysis, oxidative phosphorylation, and MAPK signal transduction, while the other included glycolysis, the TCA cycle, coenzyme A biosynthesis, sterol synthesis, and fatty acid degradation. Both types of pathways jointly affect the cell cycle. The main functions of the key genes and metabolites that have been verified as being affected are glucose synthesis and oxidative respiration, as well as citric acid synthesis, acetyl-CoA synthesis, and sterol synthesis. Both functions involve intracellular pyridine nucleotide metabolism and adenine nucleotide transformation. This study helps to reveal the synergistic mechanisms underlying the combined efficacy of biological and chemical agents, providing a scientific basis for field applications.

Mangrove endophytic fungi: Biocontrol potential against Rhizoctonia solani and biofertilizers for fragrant rice cultivation

The mangrove ecosystem has emerged as a fascinating source for exploring novel bioresources which have multiple applications in modern agriculture. This study evaluates the potential applications of mangrove endophytic fungi (MEF), such as biocontrol agents against Rhizoctonia solani and as biofertilizers for improving the yield of fragrant rice variety Malaysian Rice Quality 76 (MRQ76). Through the antagonism assays, it is observed that among the 14 MEF studied, 4 fungal isolates (Colletotrichum sp. MEFN02, Aspergillus sp. MEFN06, Annulohypoxylon sp. MEFX02 and Aspergillus sp. MEFX10) exhibited promising antagonistic effect against the pathogen R. solani compared to the chemical fungicide (Benomyl). These isolates also revealed significant production of enzymes, phytochemicals, indoleacetic acid (40.96 mg/mL) and ammonia (32.54 mg/mL) and displayed tolerance to salt and temperature stress up to 2000 mM and >40 °C respectively. Furthermore, employing the germination and pathogenicity test, inoculation of these endophytes showed lower percentage of disease severity index (DSI%) against R. solani, ranging from (24 %–46 %) in MRQ76 rice seedlings. The in-vivo experiments of soil and seed inoculation methods conducted under greenhouse conditions revealed that these endophytes enhanced plant growth (8–15 % increase) and increased crop yield (≥50 %) in comparison to control treatments. The current findings provide valuable insights into eco-friendly, cost-effective and sustainable alternatives for addressing R. solani infection and improving the agronomic performance of the fragrant rice cultivar MRQ76, contributing to food security.

Synthesis and Antifungal Activities of Novel Griseofulvin Derivatives as Potential Anti-Phytopathogenic Fungi Agents.

The extensive and repeated application of chemical fungicides results in the rapid development of fungicide resistance. Novel antifungal pesticides are urgently required. Natural products have been considered precious sources of pesticides. It is necessary to discover antifungal pesticides by using natural products. Herein, 42 various griseofulvin derivatives were synthesized. Their antifungal activities were evaluated in vitro. Most of them showed good antifungal activity, especially 3d exhibited a very broad antifungal spectrum and the most significant activities against 7 phytopathogenic fungi. In vivo activity results suggested that 3d protected apples and tomatoes from serious infection by phytopathogenic fungi. These proved that 3d had the potential to be a natural product-derived antiphytopathogenic fungi agent. Furthermore, docking analysis suggested that tubulin might be one of the action sites of 3d. It is reasonable to believe that griseofulvin derivatives are worth further development for the discovery of new pesticides.

Comparative Evaluation of In-vitro Bioefficacy of Microbial Bioagents and Novel Chemical Compounds against Fusarium oxysporum f.sp. Cubense

The Assam and North-eastern regions of India recognized as diverse repositories of wild and cultivated banana cultivars, confront a significant threat to banana varieties, Malbhog due to Fusarium wilt disease caused by Fusarium oxysporum f.sp. cubense (Foc). This study investigates the in-vitro bioefficacy of indigenous bioagents and new-generation chemical compounds against Foc to develop an integrated module subsequently, in line with the worldwide pursuit of environmentally conscientious and high-performance agricultural practices.In this study, four bioagents viz., Bacillus vallismortis, Bacillus amyloliquefaciens, Trichoderma harzianum, and Talaromyces pinophilus were screened in-vitro against Foc revealed the highest efficacy of B. vallismortis with 68.22 % mycelial growth inhibition of Foc followed by B. amyloliquifaciens with (60.05%) and the least inhibition was exhibited by T.pinophilus with (50.05%).To identify new generation chemical compounds, namely Propiconazole, Azoxystrobin, Tebuconazole + Trifloxystrobin were tested with a standard check Carbendazim wherein all the chemicals significantly inhibited the mycelial growth of the pathogen over control with Tebuconazole + Trifloxystrobin combination fungicide showing highest percent inhibition of 94% at 0.1% concentration followed by Carbendazim at 0.1%. Our study has identified potential microbial strains and chemical fungicides which can be further explored for the development and exploration of bio-fungicide and chemical fungicide-based biointensive integrated management of Fusarium wilt menace in malbhog banana in the region.

Essential oils in post-harvest disease management: Metabolic impact on Narince (Vitis vinifera L. cv) grapes against Botrytis cinerea

There is an urgent need for alternative, environmentally friendly post-harvest disease management solutions because of the growing concern over the use of chemical fungicides in agriculture and their detrimental impact on human health and the environment. This study examines the effects of thymol, eugenol, and 1,8-cineole essential oils on the sugar, organic acid, and amino acid profiles of 'Narince' grape berries as well as their effectiveness against gray mold (Botrytis cinerea). Our study has noted that the application of EOs, particularly eugenol, significantly alters the metabolic profile of 'Narince' grapes, enhancing sugar content and modifying the levels of organic acids and amino acids, which suggests a potential for improving grape quality and resistance to Botrytis cinerea. The combined use of eugenol with other EOs and fungicides, as indicated by the treatments OF and OSF, not only displayed a synergistic effect in elevating the concentration of key metabolites but also appeared to be more effective in combating fungal infection compared to individual EO applications. The PCA analysis and subsequent heatmap visualization revealed distinct metabolic clustering among the treatments, with combined EO treatments, especially those including eugenol, markedly influencing the amino acid profile of the berries. Our investigation's results suggest that EOs may offer a viable, eco-friendly alternative to traditional fungicides. Our study also adds to the body of knowledge supporting the advancement of integrated pest management strategies that are efficacious yet environmentally considerate, aligning with the global shift towards more sustainable practices in agriculture and food security.

Management of Rust in Wheat Using IPM Principles and Alternative Products

Overall, there is a major wish that European farmers implement integrated pest management (IPM), particularly to reduce dependence on pesticides. In the European Rustwatch project, partners conducted nineteen trials across nine different countries during 2020 and 2021 to investigate different IPM strategies, focusing on controlling rust diseases in winter wheat. The trials included the use of varieties with contrasting levels of resistance, variety mixtures, reduced fungicide rates, thresholds, and Decision Support Systems (DSSs), and testing alternative products to fungicides. Sixteen trials developed yellow rust (Puccinia striiformis f. sp. tritici) infections, and six trials developed brown rust (Puccinia triticina) infections. Resistant varieties proved highly effective in keeping down yellow rust infection, and variety mixtures also effectively reduced infection levels and stabilized yields. Rust was fully controlled using 25% of standard fungicide rates, even under high disease pressure. Using DSSs provided sufficient control of rust diseases and resulted in competitive net economic returns due to fewer fungicide applications. The alternative products tested included two biological control agents and four alternative chemistries, which all gave inferior and insufficient control against rust compared with chemical fungicides. The trial work demonstrated that there are good and reliable options for including IPM into disease control in wheat.

Monitoring of main tomato (Solánum lycopérsicum L.) diseases and methods of microbiological control of phytopathogens

The article highlights the main diseases of tomato plants caused by phytopathogenic microorganisms that cause great damage in many countries of the world, including Ukraine. It has been analyzed that phytopathogenic micromycetes that parasitize tomato plants cause huge losses in agricultural production, reducing the quality of products, and also release toxins that cause poisoning and numerous serious diseases that affect humans and animals that consume this product. It has been established that the most common tomato diseases caused by phytopathogenic fungi are late blight, alternaria, septoria, gray rot, spotted wilt virus, and bacterial tomato cancer. Microbiological means of control were analyzed as an alternative to chemical fungicides, which are considered safe methods in modern agriculture. They stimulate the defense mechanisms of plants, acting as inducers of plant resistance or as means of biological control. It was found that one of the common biological preparations in the fight against diseases and improving the growth of tomato culture are preparations containing Trichoderma spp. They are widely used as biofungicides against the pathogens Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii. The study of Mexican scientists on the testing of various isolates of the genus Trichoderma spp. Chinese scientists identified a strain of Pseudomonas aeruginosa (CQ-4) that can effectively control the spread of gray rot disease and identified bacteria of the genus Bacillus subtilis, which are characterized by notable antagonistic activity against a wide range of phytopathogenic bacteria and micromycetes and are a factor in biological control. Also, scientists from Egypt who conducted experiments on two endophytic fungi, namely Curvularia lunata and Nigrospora sphaerica, where their antagonistic action against phytopathogenic fungi and their ability to produce an important growth hormone and provide some necessary nutrients for plant growth were evaluated. A number of investigated antagonist strains are the basis or promising for the production of microbial preparations for controlling phytopathogens in agroecosystems and increasing the yield of tomato plants.

Controlling Botrytis gray mold in strawberry fruit by bioactive protein isolated from kidney bean

Due to the risks they pose to human and environmental health, there has been a strong push in recent times to reduce the use of chemical fungicides in phytopathogen treatment. In the present study, vicilin was isolated from kidney bean seeds and characterized by SDS-PAGE, zeta potential, and pH solubility curve. The α/ (85 KDa), α (70 KDa), and β (60 KDa) subunits were represented by three distinct protein bands in vicilin. The linear growth of B. cinerea was clearly reduced by 12.96%, 14.81%, 25.92%, 35.18%, and 40.73% in response to vicilin application at 50, 100, 200, 300, and 400 µg/ml, respectively. The scanning electron microscopy (SEM) of vicilin-exposed B. cinerea revealed hyphae enlargement and conidia distortion. Addition of vicilin from kidney bean seeds clearly reduced the disease incidence in a concentration-dependent manner (100, 200, and 400 µg/mL). The higher doses (400 µg/mL) of vicilin provided higher activity in decreasing the disease severity of the strawberry fruits. As a sustainable glycoprotein, vicilin, found in kidney bean seeds, can be used to combat postharvest fungal infections.

Antioxidant and Antifungal Properties of Cinnamon, Cloves, Melia azedarach L. and Ocimum gratissimum L. Extracts against Fusarium oxysporum Isolated from Infected Vegetables in Mauritius.

Fusarium species, a group of economically destructive phytopathogens, are poorly studied in Mauritius where agriculture holds much significance. Furthermore, the increasing popularity of organic farming has prompted interest in alternatives to chemical fungicides. After gaining an overview of Fusarium prevalence in Mauritius fields through a survey, the pathogen was isolated from infected crops and identified based on morphological and molecular characteristics. Methanol and water extracts were then prepared from Melia azedarach, Ocimum gratissimum, cinnamon and cloves before determining their phytochemical profiles. Additionally, the antioxidant and antifungal effects of different concentrations of aqueous extracts were assessed. The isolate was confirmed as Fusarium oxysporum, and cloves inhibited its growth by up to 100%, especially at 60 and 90 g/L, with the results being significantly higher than those of the synthetic fungicide mancozeb. Over 50% inhibition was also noted for cinnamon and Ocimum gratissimum, and these effects could be linked to the flavonoids, phenols and terpenoids in the extracts. This study presented the aqueous extracts of cloves, cinnamon and Ocimum gratissimum as potential alternatives to chemical fungicides. It also confirmed the prevalence of Fusarium infection in Mauritius fields, thereby highlighting the need for additional studies on the pathogen.

Effective Control of Sclerotinia Stem Rot in Canola Plants Through Application of Exogenous Hairpin RNA of Multiple Sclerotinia sclerotiorum Genes.

Sclerotinia stem rot is a globally destructive plant disease caused by Sclerotinia sclerotiorum. Current management of Sclerotinia stem rot primarily relies on chemical fungicides and crop rotation, raising environmental concerns. In this study, we developed an eco-friendly RNA bio-fungicide targeting S. sclerotiorum. Six S. sclerotiorum genes were selected for double-stranded RNA (dsRNA) synthesis. Four genes, a chitin-binding domain, mitogen-activated protein kinase, oxaloacetate acetylhydrolase, and abhydrolase-3, were combined to express hairpin RNA in Escherichia coli HT115. The effect of application of total RNA extracted fromE. coliHT115 expressing hairpin RNA on disease progressive and necrosis lesions was evaluated. Gene expression analysis using real-time PCR showed silencing of the target genes using 5 ng/µl of dsRNA in a fungal liquid culture. A detached leaf assay and greenhouse application of dsRNA on canola stem and leaves showed variation in the reduction of necrosis symptoms by dsRNA of different genes, with abhydrolase-3 being the most effective. The dsRNA from a combination of four genes reduced disease severity significantly (P = 0.01). Plants sprayed with hairpin RNA from four genes had lesions that were almost 30% smaller than those of plants treated with abhydrolase-3 alone, in lab and greenhouse assays. The results of this study highlight the potential of RNA interference to manage diseases caused by S. sclerotiorum; however, additional research is necessary to optimize its efficacy.

Antagonistic Activities of Metschnikowia pulcherrima Isolates Against Penicillium expansum on Amasya Apples.

Postharvest fungal diseases cause serious fruit losses and food safety issues worldwide. The trend in preventing food loss and waste has shifted to environmentally friendly and sustainable methods, such as biological control. Penicillium expansum is a common postharvest contaminant fungus that causes blue mould disease and patulin formation on apples. This study aimed to provide biocontrol using Metschnikowia pulcherrima isolates against P. expansum, and to understand their antagonistic action mechanisms. In vitro, 38.77-51.69% of mycelial growth inhibition of P. expansum was achieved by M. pulcherrima isolates with the dual culture assay, while this rate was 69.45-84.89% in the disc diffusion assay. The disease symptoms of P. expansum on wounds were reduced by M. pulcherrima, on Amasya apples. The lesion diameter, 41.84mm after 12 d of incubation in control, was measured as 24.14mm when treated with the most effective M. pulcherrima DN-MP in vivo. Although the antagonistic mechanisms of M. pulcherrima isolates were similar, there was a difference between their activities. In general, DN-HS and DN-MP isolates were found to be more effective. In light of all these results, it can be said that M. pulcherrima isolates used in the study have an antagonistic effect against the growth of P. expansum both in vitro and in vivo in Amasya apples, therefore, when the appropriate formulation is provided, they can be used as an alternative biocontrol agent to chemical fungicides in the prevention of postharvest diseases.

Identification of Curvularia eragrostidis (Henn.) J.A.Mey. the Leaf Spot Pathogen of Oil Palm (Elaeis guineensis Jacq.) and It’s Control by False Elder (Peronema canescens Jack) Leaf Extract

Oil palm is the main vegetable oil-producing crop in Indonesia. Leaf spot disease is one of the major diseases that attacks oil palm seedlings at all seedling stages. In Indonesia, leaf spot disease in oil palm nurseries is most commonly caused by the genus Curvularia with an infection intensity of up to 60–70%. The control of leaf spot disease usually uses chemical fungicides but its continuous use can cause the development of resistant pathogen fungi and have a long-term negative impact on the environment. False elder (Peronema canescens Jack) leaves have bioactivity as an antimicrobial control disease caused by fungal infections. In this study, Curvularia was isolated from oil palm seedlings infected with leaf spot disease from oil palm nurseries in South Sumatra. Effectiveness testing of P. canescens leaves conducted by a Completely Randomized Design method with five treatments and three replications. The fungi that caused leaf spot disease in oil palm were identified as Curvularia eragrostidis. P. canescens leaf water extract at 25% concentration was very ineffective to quite effective in controlling disease severity based on the average number of spots and diameter of spots in oil palm with the values 36.25–59.50% and 12.50–27.78%. P. canescens leaf water extract could reduce the average number of spots and diameter of spots started on day 30 after being sprayed three times with P. canescens leaf water extract so that it could be used as an alternative to control C. eragrostidis leaf spot disease in oil palm that is more friendly to the environment.

Antifungal, antioxidant, and photocatalytic activities of greenly synthesized iron oxide nanoparticles

Abstract The build-up of synthetic dyes in the environment and aquatic ecology is a significant environmental issue due to their inability to break down naturally. The overuse of chemical fungicides also poses a threat to the environment due to their accumulation and fostering of fungal resistance. Hence, the study was conducted to detect the antifungal properties and photocatalytic activity of greenly synthesized iron oxide nanoparticles (IONPs) prepared using the Hibiscus sabdariffa flower extract. The biogenic IONPs showed the highest photocatalytic activity against rhodamine B dye at a concentration of 4.0 mg/ml. The biogenic IONPs also demonstrated effective antifungal properties against Penicillium digitatum and Aspergillus niger strains, with relative inhibition percentages of mycelial growth being higher than those with the metalaxyl + mancozeb fungicide at 800 ppm concentration. The efficient photocatalytic activity of the biogenic IONPs against rhodamine B dye and their effective antifungal properties suggest their potential use as safe substitutes for commercial fungicides.

Evaluation and Control of Fusarium acuminatum Causing Leaf Spot in Saposhnikovia divaricata in Northeast China.

Saposhnikovia divaricata is an authentic Chinese herbal medicine in Northeast China named Guanfangfeng, which is made from very high-quality plants for sufficient efficacy. However, leaf spot causes a very large reduction in the yield and quality of S. divaricata in Shuangyashan (46.58°N, 131.28°E), Northeast China. A total of 18 isolates were isolated from the diseased leaves of S. divaricata, following Koch's postulates, and identified as Fusarium acuminatum based on morphological, molecular biological, and phylogenetic tree analyses. To the authors' knowledge, this is the first report of F. acuminatum causing S. divaricata leaf spot in China. F. acuminatum infected perilla and mung beans but not foxtail millet, peanuts, wheat, peas, rye, red beans, or sorghum. Susceptibility assessment of F. acuminatum to fungicides using the mycelial growth rate method showed that isolates of F. acuminatum were most sensitive to prochloraz, with effective concentration values of 0.0005413 to 0.0009523 μg/ml. In the two field experiments, the average control efficacy of prochloraz at 0.450 g/liter on S. divaricata leaf spot caused by F. acuminatum was 75.42%. Therefore, nonhost plant rotation or intercropping with suitable chemical fungicides may be used to control S. divaricata leaf spot. This study's results provide a theoretical basis for controlling S. divaricata leaf spot and will facilitate the development of effective disease management programs.