Mycelial Growth Research Articles

In Vitro Assessment of Penicillium expansum Sensitivity to Difenoconazole

Penicillium expansum causes blue mold, a major post-harvest disease affecting apples. This disease is commonly managed using fungicides, including Difenoconazole (Dif), a demethylation inhibitor (DMI) approved for its control. This investigation aims to evaluate the baseline sensitivity of 100 P. expansum isolates to Difenoconazole. The isolates were collected from symptomatic apples in 34 storage warehouses across the Fes-Meknes and Draa-Tafilalet regions over three years (2020, 2021, and 2022). The study revealed an increase in the percentage of inhibition of mycelial growth and spore germination of P. expansum proportional to the increasing concentration of the fungicide. Moreover, the results indicate that 46 isolates were able to develop even at a concentration of 5 µg/mL of Dif (the suggested discriminatory dose), indicating reduced sensitivity to this fungicide. The analysis of the values of the effective concentration to inhibit 50% (EC50) of mycelial growth of P. expansum ranging from 0.027 to 1.673 µg/mL (mean: 0.263 µg/mL, variation factor: 62.507) and for spore germination from 0.0002 to 0.787 µg/mL (mean: 0.048 µg/mL, variation factor: 4113.835). The wide variation in EC50 values indicates significant variability in the isolates’ responses to Dif, likely due to diverse sampling in space and time. Our results showed that some P. expansum isolates could grow even at high concentrations of Dif, indicating limited efficacy of this treatment. The EC50 of five isolates exceeded 0.92 µg/mL, suggesting potential resistance. This study indicates reduced sensitivity and possible emergence of resistant strains. Notably, it is the first evaluation of P. expansum sensitivity to Dif in Morocco.

Duration of Light Exposure Using White Light-Emitting Diode (LED) on the Performance of White Oyster Mushroom (Pleurotus ostreatus L.)

Background: In the dynamic world of mushroom cultivation, optimizing growth conditions is paramount for maximizing yield and quality. This research sought to evaluate the influence of varying hours of exposure to white light through light-emitting diodes (LED) on growth and yield performance of white oyster mushroom (Pleurotus ostreatus L.). Its aim was to determine the most effective light exposure duration for enhancing mushroom growth and yield. Research Design: Using a completely randomized design (CRD), the study used four treatments: 8 hours of lighting (T1), 12 hours of lighting (T2), 16 hours of lighting (T3), and a control group that received natural light (T4). The study was conducted in Palayamanan (8° 27’ 5.3118" N and 126° 9’ 59.7739" E) area at North Eastern Mindanao State University’s -Tagbina Campus from July 2023 to November 2023. Results: Results from the study provided interesting insights into the indirect nature of the relationship between light exposure and mushroom development. The findings of the study indicate that the duration of light exposure significantly affects the growth and yield of white oyster mushrooms. Both mycelium growth (29.80 days) and fruiting body formation (7.83 days), as well as harvesting time (10.87 days), were improved by 12 hours of lighting, while the control group consistently showed poor performance. Conclusion: Based from the analysis, it is evident that 12 hours of lighting consistently performed very well, with the exception of a minor under-performance in the case of yield per harvest, suggesting that 12 hours might be the ideal duration. Hence, 16 hours of lighting also demonstrated some advantages in certain variables, indicating potential for further study.

Propiconazole resistance phenotypes in Geotrichum candidum from South Carolina peaches are linked to point mutations in GcCYP51B gene.

Geotrichum candidum Link (1809) is a yeast-like fungus that causes sour rot of peach (Prunus persica). Outbreaks of the disease have occurred since 2021 in peach fruit kept in cold storage despite post-harvest treatments with propiconazole at a commercial farm in South Carolina (SC). A total of 58 isolates, 40 from symptomatic fruit from cold storage in Saluda County (SC packing house isolates), 11 from three SC orchards in Saluda County, Spartanburg County, and Pickens County (SC non-packing house isolates), and 7 California (CA) isolates (at least 3 from packing houses) were evaluated for propiconazole sensitivity. Mycelial growth assays revealed that 6 of 7 CA isolates had the lowest EC50 values and were considered sensitive (S) to propiconazole with an average EC50 value of 0.02 µg/ml and minimum inhibitory concentration (MIC) values >1 to < 3 µg/ml. Isolate 02J018 from CA and all SC non packing house isolates were considered reduced-sensitive (RS) to propiconazole with an average EC50 value of 0.33 µg/ml and MIC values >10 to <30 µg/ml. SC packing house isolates were considered resistant (R) to propiconazole and had an average EC50 value of 3.55 µg/ml and MIC values >300 µg/ml. Two CYP51 genes, GcCYP51A and GcCYP51B, encoding two demethylase inhibitor (DMI) target enzyme 14α-demethylases were identified, sequenced, and characterized. Two GcCYP51A and three GcCYP51B variants were found. While both GcCYP51A variants were linked to S isolates, the GcCYP51B2 variant possessing the mutation Y143F was found in RS, and the GcCYP51B3 variant possessing Y143F, E126K, and G460S mutations was identified in R isolates. The Y143F and G460S mutations had been associated with DMI fungicide resistance in other plant pathogens. No increased constitutive expression of GcCYP51A or GcCYP51B was observed in RS or R isolates. Detached fruit assays revealed that label rates of propiconazole controlled sour rot caused by S and RS but not R isolates. Our results suggest that sour rot outbreaks in a SC packing house were linked to target gene-induced propiconazole resistance in G. candidum.

Use of Essential Oils for the Treatment of Fusarium oxysporum f. sp. Albedinis: Chemical Profile, In Vitro Antifungal Activity, and In Silico Investigation by Molecular Docking Study

Background: Fusarium oxysporum f. sp. Albedinis a telluric fungal pathogen commonly found in soils, is the causal agent of fungal vascular wilt of date palms in Moroccan oases. The infection by the pathogen leads to the death of the date palm after six months to two years, which causes enormous economic and environmental damage. Objective: The framework of this paper is to determine the chemical composition of six essential oils using GC-MS and their antifungal activity on the mycelial growth of Fusarium oxysporum f. sp. Albedinis, as well as the molecular docking study to evaluate the inhibitory potential of fungal trypsin. Methods: The essential oils were extracted from different parts of the plants (whole plant, flowers, and leaves) by steam distillation, and were identified using gas chromatography-mass spectrometry (GC/MS). The antifungal assay of the extracted essential oils and their main components was assessed using the direct contact method with the fungus at different concentrations; the obtained results were evaluated by calculating the minimum inhibitory concentration (MIC) of each essential oil, followed by an in-silico study of the major identified compounds for better understanding of the inhibitory potential against fungal trypsin activity. Results: The identification of the different bioactive compounds using GC-MS revealed that Rosmarinus officinalis Eo was characterized by eucalyptol 46.26%, camphor 10.03%, and β-pinene 6.63%; while Lavandula officinalis Eo was endowed by the presence of linalool 14.93%, camphor 14.11%, and linalyl acetate 11.17%. Furthermore, Artemisia herba alba was rich in 1,3,5-cycloheptatriene, 1,6- dimethyl- 36.44%, camphor 22.50%, and α-thujone 7.21%. While Eucalyptus globulus was rich in eucalyptol 74.32%, β-Cymene 11.41%, α-Pinene 6.96%. Finally, Mentha pepirita and Mentha pulegium were both characterized by the presence of D-limonene 20.15%, trans-carveol 19.59%, D-Carvone 14.96%, and pulegone (42.40%), 3-cyclopentene-1-ethanol, 2,2,4-trimethyl- (11.28%), 1,3,4- trimethyl-3-cyclohexenyl-1-carboxaldehyde (9.68%), respectively. Regarding the in vitro, all Eos from different plants exhibited pronounced antifungal effect. The MIC values recorded for E. globulus were MIC= 1.75 mg/L, M. pulegium and L. officinalis (MIC= 1.80 mg/L), and M. piperita (MIC= 1.90 mg/L). The strongest inhibition potential was associated with R. officinalis EO (MIC= 1.15 mg/L) and A. herba alba EO (MIC= 1.60 mg/L). As for the computational study performed camphor one of the bioactive compounds showed its ability to act against trypsin which could be considered a potential candidate against Fusarium oxysporum f. sp. Albedinis. Conclusion: The studied essential oils from different medicinal and aromatic plants showed significant antifungal activity, probably due to the Camphor which could have an inhibitory effect on the Fusarium oxysporum f. sp. Albedinis trypsin. Further research should be conducted in vivo for a better understanding of the mechanism of action of these essential oils.

Successional changes in aphyllophorales macromycetes at different stages of coniferous xylolysis

The state of modern protective plantations in coniferous-deciduous forests of the Non-Chernozem zone is characterized by great heterogeneity. Currently, both protective forest plantations and protective tree plantations are managed by an extensive method, often without taking into account biological relationships in the agrophytocenosis. Successional changes in Aphyllophorales macromycetes (AFMM) at different stages of xylolysis of large tree debris represent a complex biochemical process. The limiting conditions for the active growth of fungal mycelium inside wood include light, access to moisture and air, violations in water transport. As mycogenic xylolysis develops, there is an increase in the biodiversity of AFMM species, which reaches a maximum at stage III–IV. On a large data set of 332 model trees and 3,543 basidiomes of xylotrophic basidiomycetes, the presence of correlations between the settlement on the substrate of various ecological groups of AFMM involved in xylolysis was established. It has also been shown that the fruit bodies of fungi are actively formed under conditions of abiotic stress and their number increases in subsequent seasons. When using AFMM as indicators of the xylolysis stage of coniferous species, it is necessary to take into account that the development of mycelium depends on the structural features of the wood. The course of mycelium development in the trunk cross-section is associated with both the action of external environmental factors and interference processes between species. At the same time, the frequency of basidioma formation and their age are of great importance in field identification.

Preparation of pH-Responsive Kas@ZnO Quantum Dots for Synergistic Control of Rice Blast and Enhanced Disease Resistance in Rice.

The construction of controlled-release formulations improves the sustained-release performance and utilization efficiency of pesticides, which are important aspects in plant protection and environmental chemistry. The current study employs kasugamycin (Kas), which is widely used to control Magnaporthe oryzae, conjugated with carboxyl-functionalized ZnO quantum dots via amide linkages to yield a pH-responsive pesticide delivery system (Kas@ZnO). Physicochemical characterizations indicated the successful preparation of the Kas@ZnO nanoparticles. In vitro drug release assessments indicated that Kas@ZnO exhibited a loading capacity of 21.05% and could effect the controlled release of Kas in an acidic environment, which is beneficial given the unique acidic microenvironment of M. oryzae. Bioactivity assays demonstrated that Kas@ZnO could simultaneously inhibit mycelial growth and spore germination. Additionally, bioactivity tests showed that the control efficacy of Kas@ZnO against rice blast reached 67.43% after 14 days of in vivo spray inoculation, which was higher than that obtained with Kas (55.50%), suggesting improved beneficial effects of Kas@ZnO application over a prolonged duration. Moreover, Kas@ZnO enhanced the activity of defense-related enzymes in rice and upregulated the expression of defense-related genes, such as OsPR2, OsPR3, OsPR5, OsWRKY45, OsLYP6, and OsNAC4. Ultimately, the biosafety assessments revealed that Kas@ZnO did not exert any harmful effects on rice and demonstrated slight toxicity toward zebrafish. These findings indicate that Kas@ZnO can function as a pH-sensitive pesticide delivery system, allowing for targeted release of the pesticide within plant tissues. This technology demonstrates significant potential for eco-friendly plant disease management.

Screening of the Candidate Metabolite to Evaluate the Mycelium Physiological Maturation of Lyophyllum decastes Based on Metabolome and Transcriptome Analysis

Lyophyllum decastes is a commercially cultivated rare edible mushroom with high dietary and medicinal value. The mycelium physiological maturation was an important factor to the yield and quality of mushrooms obtained. However, it was impossible to obtain discriminative characteristics represented the maturity level of the mycelia from morphological features. In this article, we screened a candidate metabolite for evaluating the mycelium physiological maturation by metabolomic and transcriptomic analysis during mycelial vegetative growth stages of L. decastes. The results showed that mycelial vegetative growth 55 d had reached to physiological maturation according to the yield and quality of L. decastes, which the single bottle yield (307 g/bottle), the contents of flavonoids (2.94 mg/g dry weight), and 5 flavor amino acids (glutamate 177.90 μg/g, aspartate 95.74 μg/g, phenylalanine 31.68 μg/g, tyrosine 13.79 μg/g, and alanine 10.99 μg/g) were the highest. In addition, the metabolomic and transcriptomic analysis results showed that biosynthesis of secondary metabolites and amino acid had significant different during mycelial vegetative growth stages, and glutamine may be a candidate indicator to evaluate the mycelial physiological maturation. These findings contribute to improve our knowledge of mycelium physiological maturation and it will be used to increase mushroom yield and quality.

Comparative Analysis of Some Morpho-cultural Characters of Venturia inaequalis (Apple Scab Pathogen) under Kashmir Conditions

Apple (Malus × domestica Borkh.) represents one of the most widely cultivated and economically important temperate fruit crops in the world. However, its cultivation faces significant challenges due to various fungal pathogens, particularly apple scab inflicted by Venturia inaequalis, which has a profound impact on the yield and quality of apple, resulting in substantial economic loss. The pervasive nature of V. inaequalis and its ability to damage crops poses a serious threat to sustainable apple production. In this study, the morpho-cultural characteristics of V. inaequalis were systematically analyzed and compared between the Shopian and Baramullah districts of the Kashmir Valley. Ten isolates from each district were grown on Malt Extract Agar (MEA) and Potato Dextrose Agar (PDA) for comparative analysis. The colonies were characterized by a compact hue ranging from greyish-green to blackish and exhibited a densely velvety texture. Mycelial growth was predominantly aerial, with some isolates displaying partial irregularity in colony margins, while others exhibited greater uniformity. The mean colony radii for potato dextrose agar and malt extract agar media was measured as 23.01 mm and 28.50 mm for the Shopian district, and 28.09 mm and 33.33 mm for the Baramullah district, respectively. The mean conidial spore density was recorded at 27.87 spores/cm² for the Baramullah district and 34.67 spores/cm² for the district Shopian, respectively. This variation could be attributed to several factors, including genetic diversity within the pathogen populations, differences in altitude, climate, and other environmental factors, the selection pressure exerted by fungicide applications, the emergence of novel pathogen races, and phenotypic plasticity driven by the differing agricultural practices and microclimatic conditions in the respective regions.

Citrus bliss: potassium, sodium, and calcium silicates secrets for post-harvest diseases of fruit defense

Biotic stress significantly challenges the global citrus industry. Major post-harvest issues include diseases caused by Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, Alternaria alternata, and Phytophthora citrophthora. The negative impact of chemical fungicides on the environment and health necessitates eco-friendly alternatives. This study examines the effectiveness of sodium, potassium, and calcium silicates against common citrus diseases. In vitro tests evaluated mycelial growth inhibition using silicate concentrations from 0 to 10,000 ppm after 7 days at 25°C. Sodium silicate showed the highest efficacy, completely inhibiting P. digitatum and P. italicum at 2000 ppm. Potassium and calcium silicates achieved 100% inhibition against Penicillium spp. at a concentration of 1%. In vivo tests on Sidi Aissa clementines assessed the preventive and curative effects of 1, 2, and 6% silicate salt solutions. Sodium silicate prevented 41% of brown rot, 72% of sour rot, and 100% of green mold at 6%. Calcium silicate at 6% significantly reduced blue mold and black rot by 32% and 74%, respectively. Sodium silicate was most effective in curative treatments, suggesting its potential as a pre- or post-harvest spray to control P. digitatum, P. italicum, and G. citri-aurantii.

Fludioxonil does not antagonize propiconazole activity against Geotrichum candidum.

Fludioxonil and propiconazole are frequently used fungicides for managing fungal diseases in specialty crops. They are often used in mixture to manage brown rot caused by Monilinia fructicola and sour rot caused by the yeast-like fungus Geotrichum candidum,respectively, on stone fruits. Research indicated, however, that fludioxonil can increase the expression of the ATP-binding cassette transporters CDR1 and CDR2 in the yeast Candida albicans, leading to increased resistance to DMI fungicides. In this study, mycelial growth assays and detached fruit assays were conducted with G. candidum isolates of varying sensitivity to propiconazole to investigate potential antagonism between the two active ingredients. Isolates sensitive, reduced-sensitive, and resistant to propiconazole were able to grow with or without 20 µg/ml fludioxonil on PDA containing up to 0, 3, and 30 μg/ml propiconazole and on water agar containing up to 7.5, 7.5, and 30 μg/ml propiconazole, respectively, and no antagonistic interactions were detected. Propiconazole controlled disease with or without 20 µg/ml fludioxonil equally on detached cherry fruit caused by isolates with different DMI sensitivity phenotypes. Our results indicated no detectable antagonism between fludioxonil and propiconazole that would interfere with the mixture's ability to manage sour rot of cherry.

Pathogenicity of Bacillus subtilis Against Symbiotic Fungus of Euwallacea fornicates (Coleoptera: Scolytidae) From South India.

In India, the shot-hole borer, Euwallacea fornicates, commonly known as the tea borer, infests the galleries of tea plant twigs under natural conditions and is a major pest of tea. The current investigation focuses on the antagonistic ability of Bacillus subtilis to directly inhibit the growth of plant pathogens in two different climatic regions of tea-growing area. The evaluation reveals that (a) B. subtilis can directly suppress the growth of plant pathogens (b) in the in vitro evaluation; the B. subtilis suppressed the growth of the Fusarium ambrossium, which is the nourishment for the ambrosia beetle, (c) it also revealed that the antagonistic microbes and the entomopathogens are able to control the pest population of the shot hole borer of tea. The impact of B. subtilis on mycelial growth, sporulation, and spore germination of F. ambrosium in agar medium was observed. In the field condition on the post-treatment assessments shows an average decline of 40% in both foliar and soil drenching. Hence, we recommend the antagonistic bacterium B. subtilis for including as an IPM for the management of shot hole borer in tea.

Biocontrol Ability of Strain Bacillus amyloliquefaciens SQ-2 against Table Grape Rot Caused by Aspergillus tubingensis.

Bacillus amyloliquefaciens strain SQ-2, isolated from a cured product, has been demonstrated to exhibit a highly efficacious performance against phytopathogens, including Stemphylium solani, Fusarium moniliforme, Fusarium graminearum, and Aspergillus tubingensis. In particular, with regard to A. tubingensis, which causes summer bunch rot, SQ-2 has been observed to suppress the mycelial growth of all tested grape cultivars by over 40%. Especially on Kyoho grapes, it has the highest inhibition rate of 53%. Scanning electron microscopy (SEM) confirms that SQ-2 is an effective agent for suppressing the mycelia proliferation, differentiation, and spore formation of A. tubingensis. Furthermore, an LC/MS analysis revealed that SQ-2 produces two principal lipopeptides, namely, bacillibactin and surfactin, in addition to a polyketide, bacillaene. Further analysis through gas chromatography-mass spectrometry (GC/MS) identified 41 distinct volatile organic compounds secreted by SQ-2. Transcriptomic analysis indicated that exposure to the metabolite of SQ-2 induced substantial gene expression alterations in A. tubingensis. These data suggest that B. amyloliquefaciens strain SQ-2 exhibits promising crop protection potential of inhibiting plant pathogens through the secretion of bacillibactin, surfactin, bacillaene, and VOCs.

A Diagnostic Guide for Fusarium Fruit Rot of Pumpkin and Winter Squash

Fusarium fruit rot caused by Fusarium solani f. sp. cucurbitae is an important postharvest disease impacting the global production and storage of pumpkins and winter squash ( Cucurbita spp.). The pathogen infects fruit through wounds, causing water-soaked lesions that may become sunken, coalesce, and be covered by fine mycelial growth. F. solani is soilborne and can survive long term in soil and plant debris. Storage rots impact several Cucurbita spp. grown for long-term storage. F. solani f. sp. cucurbitae has two races and is the most commonly found Fusarium species infecting cucurbits. Identification includes morphologic and PCR-based methods. This guide outlines taxonomy, symptoms, isolation, and epidemiology and provides methods to identify the pathogen.

The Microbial Metabolite Wuyiencin Potential Targets Threonine dehydratase in Didymella segeticola to Achieve Control of Tea Leaf Spot.

Tea leaf spot caused by Didymella segeticola is a disease that has recently been discovered in the tea plantations of Southwest China, and which has a significant negative impact on the yield and quality of tea leaves. Wuyiencin is a nucleotide antimicrobial that is effective against a range of fungal diseases. However, its mode of action is still unclear. The current study found that wuyiencin inhibited the mycelial growth of D. segeticola in vitro. Meanwhile, in vivo experiments confirmed that wuyiencin had a significant curative effect on tea leaf spot. Microscopic observation represented it damaged the organelles and nucleus in fungal cells. Reverse transcription quantitative PCR assays revealed that mycelium treated with wuyiencin at the half-maximal effective concentration (EC50) dosage for 1 hour exhibited 3.23 times lower expression of Threonine dehydratase (Td) gene, which is responsible for producing pyruvate. The wild type (WT) strain had a 1.77-fold higher pyruvate concentration than that in the td mutant (P < 0.05). The td mutant was more sensitive than the WT to wuyiencin treatment, with the EC50 value in the td mutant being 30.01 μg/ml, compared with 82.34 μg/ml in the WT. Molecular docking demonstrated that wuyiencin bound to Td, with a binding energy of -10.47 kcal/mol. Compared with the WT strain, wuyiencin significantly reduced ATP concentration of the td mutant strain at dosages of 80.0 and 160.0 µg/ml. In total, wuyiencin reduced Td activity, inhibited pyruvate production, and decreased ATP content in the phytopathogenic fungus, ultimately disturbing the growth of the mycelium.

Novel Aminocoumarin-Based Schiff Bases: High Antifungal Activity in Agriculture.

Structural modification is an effective way to improve the antifungal activity of natural products and has been widely used in the development of novel fungicides. In this work, a series of aminocoumarin-based Schiff bases were synthesized and characterized by 1H-NMR, 13C NMR and HR-MS spectra. The in vitro inhibition activity of all compounds was tested against four phytopathogenic fungi (Alternaria solani, Fusarium oxysporum, Botrytis cinerea, and Alternaria alternata) using the mycelial growth rate method. The results showed that most of the target compounds exhibited significant antifungal activities. In particular, compounds 5b, 5c, 5d, 5h, 5n, 7c, 7n, and 7p exhibited more effective antifungal activity than commercially available fungicides, chlorothalonil and azoxystrobin. The structure-activity relationship revealed that the electron-withdrawing groups with more electronegativity introduced at the C-3 position were effective in improving the inhibitory activity and that halogenated benzaldehydes would be necessary in the preparation of Schiff bases. The compound 5n against Fusarium oxysporum (EC50=8.73 μg/mL) and the compound 7p against Alternaria alternata (EC50=26.25 μg/mL) were much better than the positive controls (chlorothalonil and azoxystrobin). Therefore, compounds 5n and 7p could serve as promising lead compounds for the development of novel broad-spectrum fungicides, which could be useful for applications in the agriculture.

In vitro Efficacy of Different Fungicides against Leaf Blight of Sunflower

Sunflower is one of the major oilseed crops cultivated in India. Alternaria leaf blight is one of the fungal diseases of Sunflower caused due the pathogen Alternaria helianthi, which is one of the significant limitations in the cost-effective cultivation of Sunflower in India. It is estimated that 20 to 80% losses in yield and heavy defoliation have been observed due to A. helianthi causal agent of leaf blight of Sunflower. Present investigation on evaluation on efficacy of different fungicides against leaf blight of Sunflower under in vitro condition by using Completely Randomized Design was conducted at Department of Plant Pathology, Dr. Sharadchandra Pawar College of Agriculture, Baramati during. Under this study seven fungicides viz., Chlorothalonil 75% WP, Hexaconazole 5% EC, Carbendazim+Mancozeb 75% WP, Carbendazim 50% WP, Tebuconazole 25.9% EC, Propiconazole 25% EC and Azoxystrobin 23% SC were evaluated against the pathogen Alternaria helianthi causing leaf blight in Sunflower at their recommended concentration and observation on mean radial mycelial growth and percent mycelial growth inhibition of pathogen was calculated. Results revealed that among various fungicides the three fungicides viz., Hexaconazole 5% EC, Tebuconazole 25.9% EC and Propiconazole 25% EC were found most effective with minimum mean mycelial growth and having maximum and similar (94.44%) percent growth inhibition of pathogen and rest of the fungicides tested were comparatively less effective against the pathogen A. helainthi associated with leaf blight of Sunflower.

Comparative efficacy of different chemical fungicides against Sclerotium rolfsii (sacc.) causing collar rot of chickpea (Cicer arietinum L.)

Present investigation was undertaken for efficacy of fungicides like i.e., carboxin 37.5% + thiram 37.5% WS (vitavax), pyraclostrobin 100 g/L CS, propiconazole 25% EC, hexaconazole 5% EC, thiophanate methyl 70% WP, carbendazim 50% WP, mancozeb 75% WP, chlorothalonil 75% WP and captan 70% + hexaconazole 5% WP were evaluated in-vitro at three concentrations viz., 100, 125 and 200 ppm concentration against S. rolfsii on PDA by poisoned food technique. The result revealed that increase in concentration of the fungicides caused increased inhibition of mycelial growth of pathogen. Among these, carboxin 37.5% + thiram 37.5% WS (vitavax) was completely inhibited mycelial growth of pathogen at 100 ppm, 125 ppm &amp; 200 ppm. Followed by hexaconazole 5% EC in mycelial growth inhibition of 95.44, 97.22 and 100% at 100, 125 and 200 ppm, respectively. At 200 ppm both hexaconazole 5% EC and carboxin 37.5% + thiram 37.5% WS (vitavax) is statistically at par in growth inhibition. While, mancozeb 75% WP was found least effective at all concentrations against S. rolfsii. Most effective in-vitro evaluate fungicides tested for their efficacy against disease under pot experiment along with treatment application methods viz., pre-emergence drenching, seed treatment and integration of both seed treatment and post emergence seedling drenching at 7 days after germination (7 DAG) against collar rot disease of chickpea in pot experiment. All the treatments proved significantly superior when compared with inoculated control. Maximum percent reduction in PESR (100.00%) was recorded in vitavax power applied through seed treatment followed by hexaconazole recorded (90.91%) reduction in PESR. Maximum percent reduction in PESM (62.50%) was recorded in hexaconazole applied through integration of seed treatment &amp; post emergence seedling drenching at 7 DAG. Which, was followed by vitavax power observed (50.00%) reduction in PESM. Seed treatment alone reduced PESR while, integration of seed treatment and post emergence seedling drenching at 7 DAG also reduced PESM. Among treated pots highest grain yield recorded (45.90 g/pot) in hexaconazole applied through integration of integration of seed treatment and post emergence seedling drenching at 7 DAG followed by vitavax power (43.33 g/pot).

Biocontrol potential of Burkholderia gladioli STPT16 on postharvest decay of litchi fruit caused by Peronophythora litchii and Colletotrichum fructicola

Litchi downy blight (LDB) caused by Peronophythora litchii and anthracnose (AD) caused by Colletotrichum species are major pre- and postharvest disease of litchi fruit. Biocontrol agents such as Burkholderia has been applied for controlling postharvest fruit decay. In this work, an endophytic strain SZPT16 isolated from health litchi branch was identified as Burkholderia gladioli and exhibited strong antagonistic activity against mycelial growth and conidia/sporangia germination of two postharvest pathogens. Dual incubation of pathogen and biocontrol agents caused alterations in hyphal and conidial/sporangial structures and severe cell morphology changes such as mycelia deformation, cell wall collapse and cellular disorganization. Cell-free culture filtrates (CF, diluted at 25-fold) of B. gladioli SZPT16 showed an efficient inhibition on postharvest litchi decay by preharvest application (74.77 % protection) and postharvest application (64.68 % and 71.14 % protection for LDB and AD, respectively). Furthermore, UPLC-MS/MS metabolomic analysis identified 41 up-regulated differential metabolites, which mainly included nucleosides, nucleotides, and analogues, organic acids and derivatives, organic oxygen compounds, and organoheterocyclic compounds. This study firstly reported the efficacy of CF of B. gladioli SZPT16 in protecting postharvest litchi fruit against natural and inoculated pathogen infections. The overall results provide a promising alternative to chemical fungicides to control litchi postharvest decay.

Effect of beeswax and lemon grass oil on Alternaria alternata and post-harvest quality of bitter gourd during storage

ABSTRACT Alternative strategies are being utilised to extend the storage ability and preserve the quality of crops including bitter gourd. The present study was conducted to assess the potential of beeswax (BW) and lemongrass oil (LO) on the shelf life and Alternaria alternata disease of bitter gourd during cold storage. The experiment included the following treatments: (1) distilled water (control), (2) BW 5%, (3) BW 10%, (4) BW 5% + LO 0.5%, and (5) BW 10% + LO 0.5%. The bitter gourds were stored at 25°C for 15 days. The results revealed that BW 10% + LO 0.5% proved to be the best treatment followed by BW 5% + LO 0.5% and BW 10%. The BW 10% + LO 0.5% treatment exhibited inhibitory effects on mycelium growth, spore germination, disease incidence, and disease severity. It also reduced weight loss and ion leakage and conserved higher contents of titratable acidity, firmness, ascorbic acid, and total phenolic content of bitter gourd. Overall, these results revealed that beeswax and lemon grass oil can be effectively utilised to inhibit Alternaria alternate disease and prolong the storage ability of bitter gourd fruit in a cost-effective and eco-friendly way.

Bacillus velezensis B105-8, a potential and efficient biocontrol agent in control of maize stalk rot caused by Fusarium graminearum.

Maize stalk rot (MSR), caused by Fusarium graminearum, is the most serious soil borne disease in maize production, seriously affecting maize yield and quality worldwide. Microbial biocontrol agents are the best means of controlling MSR and reducing the use of chemical fungicides, such as Bacillus spp. In the study, a soil-isolated strain B105-8 was identified as B. velezensis (accession No. PP325775.1 and No. PP869695.1), demonstrated a broad spectrum against various pathogens causing maize diseases, which effectively controlled MSR, exhibited a high control efficacy of more than 60% and growth-promoting effect in the pot plant. B105-8 could effectively improve soil urease (S-UE), invertase (S-SC), and catalase (S-CAT) activities. S-NP activity showed an initial increase with a peak of 20,337 nmol/h/g, followed by a decrease, but activity remained significantly better than control treatment with chemical fungicides. The application of B105-8 repaired the damage caused by F. graminearum on soil activity. The antifungal compound B-1, extracted from B105-8, was purified using a protein purifier, revealing inhibitory effects against F. graminearum. Mass spectrometry analysis indicated the potential presence of C14 Bacillomycin, C15 Iturin, C15 Mycosubtilin, C17, and C15 fengycin in B-1. In pot experiments, a 5 μL/mL concentration of B-1 exhibited 69% control on MSR, enhancing maize root elongation, elevation, and fresh weight. At 10 μL/mL, B-1 showed 89.0 and 82.1% inhibition on spore production and mycelial growth, causing hyphal deformities. This study presents the innovative use of B. velezensis, isolated from maize rhizosphere in cold conditions to effectively control MSR caused by F. graminearum. The findings highlight the remarkable regional and adaptive characteristics of this strain, making it an excellent candidate to fight MSR in diverse environments. In conclusion, B. velezensis B105-8 demonstrated potential as a biocontrol agent for MSR.