Inhibition Of Mycelial Growth Research Articles

Novel Fungicide from Waste Oil Palm Fruit Bunch for Sustainable Management of Tomato Wilt Disease Caused by Fusarium oxysporum - experimental and in silico studies

Novel Fungicide from Waste Oil Palm Fruit Bunch for Sustainable Management of Tomato Wilt Disease Caused by Fusarium oxysporum - experimental and in silico studies

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.

Management of Rhizoctonia blight of groundnut using antagonistic effects of bioagents and organic amendments

Rhizoctonia blight disease caused by Rhizoctonia solani in groundnut crop is one of the most devastating diseases occurring worldwide. The disease affects the morphological and physiological parameters of the crop leading to reduction in pod yield as well as oil yield. The pathogen was isolated locally and identified as Rhizoctonia solani based on molecular characterization. The efficacy of different bioagents in reducing the radial growth of pathogen was tested in vitro and highest mycelia growth inhibition was recorded by Trichoderma asperellum (89.07 %). Among the fungicides tested, 100 % mycelial growth inhibition was observed by use of Carbendazim 50 WP, Tebuconazole 25.9 % EC, Hexaconazole 5 % suspension concentrate (SC) and Tebuconazole 50 % + Trifloxystrobin 25 % water-dispersible granule (WG). Among different organic substances tested in vitro, neem seed cake achieved maximum mycelial growth inhibition of 50.74 % and 54.08 % at 10 % and 20 % concentrations respectively. In the field experiment, treatment with application of neem seed cake to the soil at 500 kg/ha + application of mustard seed cake to the soil at 500 kg/ha + treatment of seeds with Tebuconazole at 1.5 g/kg of seed + treatment of seeds with T. asperellum at 10 g/kg of seed was found to be the best in enhancing plant health, growth promotion and oil yield. The combined treatment of bioagent, fungicide and organic amendment recorded maximum number of branches (14.00), number of leaves (668.33), plant dry weight (64.17 g), 100 pod weight (65.00 g) and oil yield (47.33 %) compared to the control and other treatments along with reduction of the disease (59.61 %). In the physiological parameters study, the same treatment also recorded maximum pigment contents viz. Chlorophyll a (1.843 mg/g), Chlorophyll b (0.555 mg/g), total chlorophyll (2.397 mg/g) and carotenoid content (0.084 mg/g) but with minimum phenol content (1.693 mg/g). Thus, it can be concluded that integration of selective inputs in the combined treatment of Neem seed cake, Mustard seed cake, Tebuconazole and T. asperellum could enhance the plant health, morphological growth and physiological parameters and increased the oil yield in groundnut along with reduction of the disease.

The growth‐promoting effects of Bacillus amyloliquefaciens W82T‐44 on soybean and its biocontrol potential against soybean Phytophthora root rot

AbstractThe most devastating soilborne disease of soybean is Phytophthora root rot (PRR) caused by Phytophthora sojae. Biological control has emerged as an effective method of reducing soilborne diseases. The present study isolated the bacterial strain W82T‐44 from the rhizosphere soil of a resistant soybean variety Williams 82. This strain was identified as Bacillus amyloliquefaciens and exhibited a 92.4% inhibition of mycelial growth of P. sojae. W82T‐44 produced cellulase, siderophore and protease and significantly promoted soybean growth. W82T‐44 treatment, compared to the negative control, was found to significantly (p < 0.05) increase soybean plant height (22.34 vs. 18.47 cm), fresh weight of the whole plant (2.57 vs. 2.05 g), dry weight (0.43 vs. 0.32 g), total root length (266.80 vs. 182.53 cm), root area (27.10 vs. 17.84 cm2) and root volume (1.88 vs. 1.16 cm3). The fermentation filtrate of W82T‐44 had significant inhibitory effects on mycelial growth, oospore formation and cyst germination in P. sojae and additionally promoted zoospore encystment. W82T‐44 possessed genes involved in lipopeptide synthesis, including bacilysin, surfactin, fengycin and bacillomycin. Moreover, it significantly upregulated pathogenesis‐related genes (β‐1,3‐glucanase, nonexpressor of pathogenesis‐related gene 1, chitinase) and genes encoding defence enzymes (polyphenol oxidase, phenylalanine ammonia‐lyase, peroxidase) in soybean roots (p < 0.05). The PRR disease index of soybean treated with the W82T‐44 strain was significantly lower (11.67) than the negative control (40.00; p < 0.05). The present study indicates the potential of B. amyloliquefaciens W82T‐44 as a biological control agent against PRR from various perspectives.

Evaluation of Fungicides against Fusarium pallidoroseum (Cooke) Sacc. causing Wilt of Coriander In vitro

Coriander (Coriandrum sativum L.) is one of the most important spice crop known to affect by various diseases. Among them, coriander wilt causes serious problems and it is also caused by a newly reported causal agent Fusarium pallidoroseum (Cooke) Sacc. Hence, F. pallidoroseum being new pathogen on coriander, a laboratory experiment was conducted to study the efficacy of different non-systemic fungicides at 1000, 1500 and 2000 ppm; systemic fungicides at 100, 250 and 500 ppm and ready-mix fungicides at 500, 750 and 1000 ppm concentrations against F. pallidoroseum using Poisoned Food Technique. The results revealed that, among non-systemic fungicides, copper oxychloride 50 WP at all concentration found significantly superior with cent per cent mycelial growth inhibition. In contrast, propineb 70 WP found least effective at 1000 ppm concentration (2.71%). Among systemic fungicides, flusilazole 40 EC and thiophanate methyl 70 WP each at 500 ppm concentration gave cent per cent mycelial growth inhibition of F. pallidoroseum. While, kresoxim methyl 44.3 SC found least effective at 100 and 250 ppm concentration (9.74 and 12.95%). Among ready-mix fungicides, prochloraz 5.7 + tebuconazole 1.4 ES at all concentration and azoxystrobin 18.2 + difenoconazole 11.4 SC at 1000 ppm concentration found effective and showed cent per cent mycelial growth inhibition of F. pallidoroseum. While, fluxapyroxad 25 + pyraclostrobin 25 SC at 500 ppm found least effective (18.34%).

Green Silver Nanoparticles and Their Activity as Antifungal Agents Against Penicillium digitatum Causing Green Mould of Citrus

AbstractThe green synthesis of silver nanoparticles (SNPs) using aqueous extracts of five plants viz., Ocimum americanum, Azadirachta indica, Allium sativum, Eucalyptus hybrida, Zingiber officinale were evaluated for their antifungal property against Penicillium digitatum, a green mould pathogen of citrus fruits. The five plant species were selected from a screening of aqueous extracts from 16 plant species. The efficacy of aqueous extracts, at 50 % concentration, ranged from 14.44–68.52 % inhibition in mycelia growth of P. digitatum. Among SNPs, O. americanum was found most efficacious, at 1000 ppm concentration, with 80.7 % mycelial inhibition followed by A. indica with 77.4 % mycelial growth inhibition of fungal pathogen. Further, physical and structural characterization of SNPs of O. americanum and A. indica was carried out. The characterization analysis executed via transmission and scanning electron microscope revealed size distribution and nanoparticles were spherical to irregularly shaped ranging from 22.8–250 nm in O. americanum and 26.5–500 nm in A. indica. In UV‐visible spectrophotometer, the absolute absorption peak was recorded at 448 nm and 442 nm for O. americanum and A. indica, respectively. FTIR analysis of SNPs of A. indica and O. americanum confirmed the presence of carboxyl, amide group and secondary amines which were the main constituent of proteins. The novelty of the present study is in the green synthesis of silver nanoparticles with potential in the management of postharvest pathogens of fruit crops. The synthesis of SNPs used in this study is simple, environmentally benign and cost‐effective using aqueous extract of native plants.

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.

Efficacy of Different Fungicides against Leaf Blight of Carrot Caused by Alternaria alternata (Fr.) Keissler

Background: Leaf blight disease is painful nerve to carrot growing farmer because it causes huge economic loss to the farmer every year. Leaf blight of carrot is seed and soil borne disease causes by Alternaria alternata. Hence management of the disease by fungicides is the best alternative. Therefore, in the present investigation, our main emphasis was to identify best fungicide for management of leaf blight of carrot. Methods: Seven fungicides were tested against leaf blight pathogen (Alternaria alternata) in lab as well as in cage house condition. The experiment was conducted at Cage house of department of Plant Pathology, COA, Jodhpur during Rabi-2020-21. Result: Among all the fungicides used in the present investigation, difenoconazole 25% inhibited the 100% mycelial growth at all the concentrations. The next best treatment was tebuconazole 50%+trifloxystrobin 25% inhibited the 99.02% mycelial growth and Minimum mycelial growth inhibition was observed in mancozeb 75% WP followed by carbendazim 12%+mancozeb 63% 61.58% and 77.70%, respectively; along with control plate was showed 100% mycelium growth. The superior treatments under in vitro carry forward in vivo condition. When applied as foliar application under cage house condition, difenoconazole 25 EC at 0.25 ml/lit (11.17%) was observed lowest disease incidence.

Evaluation of compatibility of various chemical fungicides with Cordyceps militaris (L.)Link

Cordyceps militaris is a well-known entomopathogen currently being explored for its mycoparasitic ability against plant pathogens. The compatibility of C. militaris was tested against various group of fungicides at systemic (0.075%, 0.050%, 0.100% and 0.150%) and non-systemic doses (0.25%, 0.50%, 0.75% and 1.00%) to assess whether they can effectively coexist or be used in combination with fungicide treatments in integrated disease management scheme. It was observed that C. militaris showed highest compatibility with copper oxychloride with the least mycelial growth inhibition (15.34±0.53%) even at the highest concentration (1.00%). Among systemic fungicides, azoxystrobin and metalaxyl were found to be compatible with C. miltaris only at lower concentrations upto 0.25 per cent and showed a 100 per cent inhibition of mycelial growth at concentration more than 0.25 per cent whereas carbendazim was incompatible at all the tested concentrations.

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.

Comparative in vitro evaluation of fungicides against collar rot pathogen, Sclerotium rolfsii in elephant foot yam

Amorphophallus or elephant foot yam (Amorphophallus paeoniifolius) popularly known as the ‘King of tubers’ is one of the major tuber crops grown in India and other parts of the world. Collar rot disease, caused by Sclerotium rolfsii is one of the primary obstacles to tuber cultivation which can significantly reduce yield up to 100%. Saprophytic nature, broad host range, and ability to produce resting structures make it difficult to manage. In this experiment, 10 isolates of S. rolfsii were isolated by the surveying Thiruvananthapuram, Kollam and Alappuzha districts of Kerala, proved the pathogenicity by inoculating the pathogen cultured in sand- maize meal media (9:1). The isolate I3 obtained from Thiruvananthapuram district was found to be the most virulent based on the days taken for symptom development (4 days). Six fungicides (copper oxy chloride (50% WP), mancozeb (75% WP), propiconazole (25% EC), carbendazim (50% WP), trifloxystrobin (25%) + tebuconazole (50%) 75 WG, and carbendazim (12%) + mancozeb (63%) WP @ 50, 100, 250, 500, 1000 and 2000 ppm were evaluated in vitro for their efficacy in inhibiting the fungal mycelial growth and sclerotia formation in isolate I3. All fungicides except carbendazim 50% WP and copper oxy chloride 50% WP, considerably reduced the mycelial development of S. rolfsii. Mancozeb 75%WP and trifloxystrobin (25%) + tebuconazole (50%) 75WG, showed complete inhibition of mycelial growth even at a lower concentration of 50 ppm.

Biocontrol of citrus melanose Diaporthe citri by Bacillus subtilis M23

Biocontrol of citrus melanose Diaporthe citri by Bacillus subtilis M23

Pyrolysed maize feedstock utilization in combination with Trichoderma viride against Macrophomina phaseolina

Maize cultivation is under the growing threat of charcoal rot (Macrophomina phaseolina). Chemical control of diseases imparts serious health hazards to humans and the ecosystem. Biochar as an alternative disease management approach has been under consideration of the researchers for some time now. The biochar utilized in this study was derived from maize stalks and cobs. Crystallographic structure, inorganic minerals content and size of maize biochar were analyzed by powder X-ray diffractometer, while scanning electron microscopy revealed rough, irregular, tubular structure of the biochar surface. EDX spectra revealed that the maize biochar composition was dominated by ‘C’ followed by ‘O’. The current study was designed to determine the synergistic effect of maize biochar (MB), and biocontrol agent (BCA) Trichoderma viride as soil amendments on the suppression of M. phaseolina. In vitro bioassays were conducted to check the efficiency of antagonistic effect of Trichoderma spp., in combination with maize biochar. On the basis of maximum mycelial growth inhibition T. viride was selected for a glasshouse experiment. Maize plants were grown in pots containing a mixture of soil with MB at application at the rate of 3 and 6% (v/v) separately, associated with or without T. viride. Treatments amended with 3% MB inoculated with M. phaseolina significantly reduced the percentage disease severity index by 40%. While in the presence of T. viride, 3% MB showed maximum disease suppression and a minimum percentage severity index i.e. 60 and 20%, respectively. Highest nitrogen contents were 18.4 g kg−1 observed in treatment 6% MB, while highest phosphorus and potassium contents were 3.11 and 15.2 g kg−1, respectively in the treatment with 3% MB. Conclusively, the effect of variable concentrations of maize biochar and T. viride as soil amendment was evident on the development of charcoal rot, growth and physiology of maize plants. According to the available literature, our report is the first on the implementation of biochar in synergism with T. viride to suppress the charcoal rot in maize.

In vitro Evaluation of Efficacy of Fungicides Against Fusarium oxysporum f. sp. Lycopersici (Sacc.) Synder and Hansen Causing Wilt Disease of Tomato

Fusarium wilt of tomato caused by Fusarium oxysporum f.sp. lycopersici is one of the most devastating and economically important fungal diseases of tomatoes. The study was conducted to assess the effectiveness of commercially available fungicides against Fusarium oxysporum f. sp lycopersici, a Nepali isolate by poisoned food technique. The experiment was carried out in a Completely Randomized Design (CRD) with five replications, in the Plant Protection Laboratory of the Ministry of Industry, Agriculture and Cooperatives, Jhumka, Sunsari. Six different fungicides: Mancozeb, Copper oxychloride, Carbendazim, Azoxystrobin, Kasugamycin + Copper oxychloride, Azoxystrobin + Difenoconazole at four different concentrations (100 ppm, 150 ppm, 200 ppm and 250 ppm) were tested for their ability to inhibit mycelial growth of the fungus, in vitro. The mycelial growth of the fungus was measured at 2, 4, 6, 8 and 10 days after inoculation (DAI). Among these fungicides Carbendazim, at all concentrations, showed the highest mycelial growth inhibition (100%) followed by Azoxystrobin in combination with Difenoconazole (82.79%) and Azoxystrobin alone (61.04%) at 250 ppm on 10 DAI. The results suggest that Carbendazim was the most effective at the lowest concentration (100 ppm) at in vitro inhibition of the fungus. Therefore, it can be a candidate to be explored for in vivo management of fusarium wilt of tomato caused by Fusarium oxysporum f.sp. lycopersici.

Resistant risk and resistance mechanism of florylpicoxamid in Colletotrichum gloeosporioides isolated from Chinese walnut

Colletotrichum gloeosporioides is the causal pathogen for the devastating walnuts anthracnose. A novel quinone inside inhibitor (QiI) fungicide florylpicoxamid has strong inhibitory efficacy against C. gloeosporioides. This study looked into the resistance risk and mechanism of C. gloeosporioides to florylpicoxamid. The basal level sensitivity of C. gloeosporioides isolates (n=102) to florylpicoxamid was established with an average 50% mycelial growth inhibition concentration (EC50) value of 0.069±0.035μg/mL. Six stable florylpicoxamid-resistant mutants with resistance factors of >1000 were produced. The fitness of every mutant was much lower than that of their parental isolates. In general, the resistance risk of C. gloeosporioides to florylpicoxamid would be moderate. Molecular docking results revealed that the amino acid substitutions A37V, and S207L in CgCytb lead to a reduction in the binding affinity between florylpicoxamid and CgCytb, indicating that these two mutations (S207L and A37V in CgCytb) indeed confer florylpicoxamid resistance in C. gloeosporioides. These findings offer a fresh viewpoint on the mechanism underlying QiI fungicide resistance and could support the prudent application of florylpicoxamid in the future to combat walnut anthracnose.

Plant-derived citronellol can significantly disrupt cell wall integrity maintenance of Colletotrichum camelliae

Anthracnose, a fungal disease, commonly infects tea plants and severely impacts the yield and quality of tea. One method for controlling anthracnose is the application of citronellol, a plant extract that exhibits broad-spectrum antimicrobial activity. Herein, the physiological and biochemical mechanism by which citronellol controls anthracnose caused by Colletotrichum camelliae was investigated. Citronellol exhibited excellent antifungal activity based on direct and indirect mycelial growth inhibition assays, with EC50 values of 76.88mg/L and 29.79μL/L air, respectively. Citronellol also exhibited good control effects on C. camelliae in semi-isolated leaf experiments. Optical and scanning electron microscopy revealed that citronellol caused C. camelliae mycelia to thin, fracture, fold and deform. Transmission electron microscopy revealed that the mycelial cell walls collapsed inward and separated, and the organelles became blurred after treatment with citronellol. The sensitivity of C. camelliae to calcofluor white staining was significantly enhanced by citronellol, while PI staining showed minimal fluorescence, and the relative conductivity of mycelia were not significantly different. Under citronellol treatment, the expression levels of β-1,3-glucanase, chitin synthase, and chitin deacetylase-related genes were significantly decreased, while the expression levels of chitinase genes were increased, leading to lower chitinase activity and increased β-1,3-glucanase activity. Therefore, citronellol disrupted the cell wall integrity of C. camelliae and inhibited normal mycelial growth.

Characterization of Botrytis cinerea, the causal agent of tomato grey mould, and its biocontrol using Bacillussubtilis

Characterization of Botrytis cinerea, the causal agent of tomato grey mould, and its biocontrol using Bacillussubtilis

Phenolic Compounds Synthesized by Trichoderma longibrachiatum Native to Semi-Arid Areas Show Antifungal Activity against Phytopathogenic Fungi of Horticultural Interest

Fungal diseases are a major threat to the horticultural industry and cause substantial postharvest losses. While secondary metabolites from Trichoderma sp. have been explored for their antifungal properties, limited information exists on the phenolic compounds produced by less studied species like Trichoderma longibrachiatum. In this study, phenolic compounds were extracted from a liquid culture of T. longibrachiatum using various solvents and methods (conventional and ultrasonic-assisted). Phenolic compounds were quantified by spectrophotometry and identified by high-performance liquid chromatography with diode array detection (HPLC-DAD). The antifungal activity against Alternaria alternata and Fusarium oxysporum was determined by mycelial growth inhibition assays, maximum growth rate (µmax) by the Gompertz equation, and spore germination tests. Although no significant differences (p ≥ 0.05) were found between the extraction methods, the type of solvent significantly influenced the phenolic content (p ≤ 0.05). Extraction with 70% ethanol showed the highest content of phenolic compounds and flavonoids. More than eight phenolic compounds were detected. Further, this is the first report of the phenolics ferulic, chlorogenic and p-coumaric acids identification in T. longibrachiatum, along with flavonoids such as epicatechin and quercetin, among others. The 70% ethanolic extracts notably inhibited the mycelial growth of A. alternata and F. oxysporum, reducing their maximum growth rate by 1.5 and 1.4 mm/h, respectively. Furthermore, p-coumaric and ferulic acids significantly inhibited spore germination of both pathogens, with a minimum inhibitory concentration (MIC) of 1.5 mg/mL and a minimum fungicidal concentration (MFC) of 2 mg/mL. These findings demonstrate the potential of T. longibrachiatum and its phenolic compounds as viable alternatives for biological control in horticulture and postharvest disease management.

Synergistic biocontrol mixture: free-cell extract with β-glucanase activity and chitosan against Thielaviopsis paradoxa, Colletotrichum gloeosporioides, and Rhizopus stolonifer

Biocontrol, which uses antagonistic microorganisms to manage plant diseases, holds promise for reducing postharvest losses but faces challenges due to varied pathogen responses. In response, biocontrol mixtures were proposed to enhance the antagonistic effect. This study evaluates the efficacy of chitosan and extracellular glucanase (EG) from Wickerhamomyces anomalus, both individually and combined, against Thielaviopsis paradoxa, Colletotrichum gloeosporioides, and Rhizopus stolonifer. The maximum inhibition of mycelial growth by chitosan for these fungi was 90.25% at 3 mg/mL, 14.2% at 5 mg/mL, and 56.28% at 3 mg/mL, respectively. Additionally, chitosan significantly inhibited spore germination across all fungi. While W. anomalus cells prevented mycelial filament association, EG alone had minimal impact on mycelial development but inhibited spore germination in a concentration-dependent manner. Combining EG with chitosan enhanced spore germination inhibition, notably achieving 98.18%. The biocontrol mixture effectively protected fruit under laboratory-controlled conditions, suggesting a robust biocontrol strategy for postharvest fungal disease management.

Role of fungicides to control blossom blight and fruit rot the main symptoms of olive anthracnose in Uruguay

Olive anthracnose caused by Colletotrichum is the most destructive olive disease worldwide causing blossom blight and fruit root. The in vitro effect of 14 fungicides from six chemical groups on the mycelial growth inhibition of Colletotrichum acutatum s.s., Colletotrichum nymphaeae, and Colletotrichum fioriniae isolates were evaluated. Tebuconazole, pyraclostrobin, and ziram significantly inhibit the mycelial growth of Colletotrichum spp. The effectiveness of these three fungicides was evaluated on detached flowers and copper oxychloride, cuprous oxide, and copper calcium sulfate on detached fruits. Arbequina, Frantoio, Coratina, and Picual cultivars inoculated with these Colletotrichum species were used. Over the flowers, fungicides caused a delay in the appearance of blossom blight between 24 and 48 h and a reduction in the disease incidence by more than 60%. Over the fruits, copper-based fungicides in general failed to reduce the anthracnose severity. This study presents the potential of some fungicides to be used for olive anthracnose control in an integrated management strategy.