Radial Mycelial Growth Research Articles

In Vitro Control of Pathogenic Fungi Associated with Selected Brri Rice Varieties

The present study evaluated the efficacy of five chemical fungicides, viz., Capvit 50 WP, Cynil 72 WP, Kochi 80 WDG, Sinozim 50 WP and Ridomil Gold MZ 68 WG along with five plant extracts, specifically Azadirachta indica A. Juss., Adhatoda vasica Nees., Psidium guajava L., Cassia alata L. and Citrus limon on the radial mycelial growth of two pathogenic fungi, Curvularia lunata and Drechslera oryzae associated with newly released BRRI rice varieties at varying concentrations. Capvit 50 WP exhibited complete inhibition of C. lunata at 300, 400 and 500 ppm concentrations as well as D. oryzae at 200, 300, 400 and 500 ppm concentrations leading the selected fungicides, followed by Cynil 72 WP and Ridomil Gold MZ 68 WG. Out of the five plant extracts, P. guajava demonstrated maximum radial growth inhibition (72.2%) against C. lunata at 20% concentration followed by A. indica. (56%), A. vasica. (52.3%), C. alata (24%) and C. limon (18.1%). Capvit 50 WP and Cynil 72 WP, among the fungicides, are potential in vivo controls for the tested pathogens associated with rice varieties. Additionally, out of the five plant extracts, Psidium guajava L. can be effective against C. lunata, while Azadirachta indica A. Juss. is a promising botanical fungicide against D. oryzae. Bioresearch Commu. 10(1): 1393-1397, 2024 (January)

Efficacy of different fungicides on wheat blast disease caused by M. oryzae pv. triticum in vitro and vivo condition

The experiment was studied to evaluate the fourteen different fungicides against M. oryzae pv. triticum in laboratory and pot experiment from August 2016 to October 2017. The result of the in-vitro evaluation showed that a 100% reduction of radial mycelial growth was obtained in Amiscore 32.5 SC, Bavistin DF, Cabrio Top, Xtracare 300 EC, Nativo 75 WG, Provax 200 WP and Trooper 75 WP. Nativo 75 WG (0.2%) revealed the highest (85.38%) reduction of disease incidence over control while Provax 200 WP (0.3%) showed an efficacy of 82.14% in reducing disease incidence in the pot experiment. The lowest (3.70%) disease severity was found in Nativo 75 WG, and Provax 200 WP also exhibited 4.40% disease severity. A maximum number of healthy grain/ear (16.40) was observed in Nativo 75 WG, and Provax 200 WP was demonstrated with healthy grain (15.00), which was close to Nativo 75 WG. In grain weight/ear, Nativo 75 WG (0.2%) led to an impressive increase of 160.47% over control.

Effect of Different Concentrations of Nano-Fungicides on Mycelial Radial Growth of Phytophthora infestans

Potato (Solanum tuberosum L.) popularly known as the “King of Vegetables” is a starchy, tuberous crop, that belongs to the family Solanaceae. Potatoes play an important role in the daily human diet because they are a copious source of minerals, vitamins, antioxidants and micronutrient. The potato is a basically temperate crop, but it grows under a wide range of climatic conditions. Potato crop is generally affected by different types of biotic and abiotic diseases. Among all diseases, Late blight of potato, caused by the Phytophthora infestans (Mont) de Barry is one of the most devastating diseases of potato worldwide. In India, the losses caused by the disease are 10-20% in Uttar Pradesh, 10-15% in West Bengal and Punjab, 10-15% in Karnataka and Uttrakhand also have been reported during 2013-14. The management of the disease can be done through cultural, mechanical, use of the resistant variety, biological and chemical, etc. The efficacy of current strategies for the management of disease is limited. Considering the destructive nature of pathogen and lack of efficient control measures, the development of alternative or complementary approaches for the management of this disease is highly desirable. However reported use of the same chemicals may raise resistant strain among the pathogens. Therefore, the use of Nano-fungicidal control of spot blotch disease cannot be overstated. However, the disease can be managed with various nanofungicides under in vitro conditions assessed for their efficacy against the disease. The effect of four nanofungicides i.e., Agritec nanofungicide, Silver nanofungicide, Selenium nanofungicide and Nickel nanofungicide against P. infestance was evaluated at different concentrations (50, 75 and 100 ppm) by poison food technique. The in vitro experiment revealed a noticeable reduction in the radial mycelial growth of P. infestance as the concentration of nanofungicides increased. Specifically, at 7 days after inoculation (DAI), the following nanofungicides at a concentration of 100 ppm exhibited the highest levels of mycelial growth inhibition when compared to the control: Silver nanofungicide (72.45%), Agritec nanofungicide (70.21%), Selenium nanofungicide (68.77%), and Nickel nanofungicide (64.65%).

In-vitro Assessment of Different Culture of Media on the Isolation and Purification of Cauliflower Alternaria Leaf Spot Disease Caused by Alternaria brassicicola (Schwein)

Alternaria leaf spot of cauliflower caused by Alternaria brassicicola (Schwein.) Wiltshire, is a significant disease of cauliflower in the Kanpur region. In the current study the pathogenic fungus was purified from infested cauliflower leaves on potato dextrose agar medium, Following inoculation on healthy cauliflower seedlings the pathogenicity of the causal agent was demonstrated. The results revealed that the fungus was Alternaria brassicicola based on common symptoms on foliage, microscopic findings, and culture characteristics of the fungus. Based on microscopic observation, the causal agent was identified as Alternaria brassicicola (Schwein.) Wiltshire. To proceed to the isolation and purification of the fungus, eight culture media were tested among which the potato dextrose agar medium was found most suitable and encouraged maximum radial mycelial growth (89.07mm) of A. brassicicola. The second best was Corn Meal Agar medium (67.46mm), followed by Potato carrot agar medium (54.83 mm), Rose Bengal agar (53.00 mm), Czapex dextrose agar (40.40 mm), Yeast Extract Agar (32.28 mm), and Nutrient Agar (24.28 mm), While minimum (22.16 mm) growth was recorded in Starch Agar. Thus, potato dextrose agar can therefore be used in the isolation, purification and pathogenicity of A. brassicicola.

Inhibitory Effect of Nano-Fungicides and Fungicides on Radial Mycelial Growth of Bipolaris sorokiniana Causing Spot Blotch of Wheat under in vitro Condition

Bipolaris sorokiniana (Sacc.) Shoem, causing spot blotch of wheat is most important disease of wheat in north eastern plains zone (NEPZ) representing warm and humid climate in India as well as in other South Asian countries. The disease is known to cause yield losses up to 50% as well as deterioration in seed quality. The present study is carried out to check inhibitory effect of nanofungicides and fungicides against Bipolaris sorokiniana. Among nanofungicides, silver nanofungicide at 100 ppm was found highly effective and inhibit the growth by 86.10% followed by agritec nanofungicide (81.41%) and selenium nanofungicide (77.01%). Among fungicides, maximum inhibition (82.57%) was observed in propiconazole at 0.2% followed by hexaconazole (78.96%) and folicure (75.92%) under in vitro condition.

In-Vitro Efficacy of Botanical extracts for the Management of Aspergillus flavus growth in Tanzania

Maize is one of the most important food and commercial crops in Tanzania but is vulnerable to pre-and postharvest contamination with aflatoxins produced mostly by Aspergillus flavus. This study evaluated the in-vitro antifungal efficacy of five locally available botanicals (Azadirachta indica, Calotropis procera, Euphorbia hirta, Jatropha curcas, and Ricinus communis) against the growth of A. flavus. The botanical leaves were collected mainly from the Kongwa district, while strains of Aspergillus species were isolated from maize grain from Kongwa and Morogoro rural districts during the cropping season 2021/2022. The effect of botanicals on the radial mycelium growth of A. flavus was tested at concentrations of 0.2 0.25, 0.3, and 0.35 g/mL. The inhibitory effect was proportional to the concentration of botanicals. The highest radial growth inhibition of A. flavus was exhibited by extracts of J. curcas (69.7%), R. communis (62.8%), A. indica (61.8%), and E. hirta (52.4%). The least mean inhibition was found in C. procera (45.7%) at a concentration of 0.35 g/ml. The antifungal effect of botanicals demonstrated in this study warrants further evaluation for pre-harvest management of Aspergillus species contamination under field conditions.

Utilization of Lignocellulosic Substrates on Oyster Mushroom (Pleurotus citrinopileatus) Cultivation

Background: Mushroom cultivation increased throughout the world with the utilization of crop residues. Oyster mushroom (Pleurotus spp.) is suitable for most of the area and less expensive for cultivation with the availability of paddy straw. Increasing demand of paddy straw compels to search alternate source of substrate for mushroom production. Based on this information efforts were taken to compare many locally available leaf substrates for Pleurotus citrinopileatus production. Methods: Leaf substrates viz., teak, bamboo, maize, banana, coconut, mango, sugarcane bagasse and grass (Dactyloctenium aegyptium) were tested for the cultivation of P. citrinopileatus. Grain substrates viz., paddy, cumbu, bengal gram, green gram, sorghum, black gram, ragi and the above leaf substrates were studied for their effect on radial mycelial growth and dry weight of P. citrinopileatus. Result: All the leaf substrates were on par with each other for radial mycelial growth. Highest mycelial dry weight of 724.67 mg was recorded in paddy straw. Among the different leaf substrates used for mushroom bed preparation, banana leaf substrates showed highest yield of 115.00 g than paddy straw. Weight of mushroom spent bed was recorded to observe the utilization of substrates in which bamboo was decomposed at the maximum. Addition of grain substrates enhanced the growth of mycelium.

Anti-Fungal Properties of Plant Extracts in vitro against Alternaria solani, the Cause of Early Blight in Potato

Early blight, caused by Alternaria solani is one of the destructive diseases of potato. An in vitro experiment was conducted using the poisoned food technique to evaluate the efficacy of acetone extracts of six plant species on the mycelial growth of A. solani. Plant extracts of Artemisia vulgaris, Melia azedarach, Parthenium hysterophorus, Datura stramonium, and Justicia adhatoda at concentrations of 0.1%, 0.5% and 5% prepared from Soxhlet extraction were mixed well in the molten potato dextrose agar (PDA) media and poured into petri plates (90 mm Ø). PDA media treated with a fungicide mancozeb was positive control while the untreated media was negative control. The poisoned plates were inoculated with a 4 mm diameter agar plug of seven days old actively growing A. solani and incubated at 26 ± 2 °C, The radial mycelial growth was recorded after 3rd, 5th, 7th and 9th days of incubation and percentage inhibition growth was calculated by comparing it with negative control plates. Artemisia vulgaris significantly inhibited colonial growth at 0.1% and 0.5% concentrations by 36.07% and 12.48%, respectively, at 5th day of inoculation (dai) as compared to negative control. M. azedarach (0.72%), P. hysterophorus (10.17%) and D. stramonium (10.20%) were moderately inhibitory in effect at 1% concentration while J. adhatoda did not possess inhibitory effect on the mycelial growth of A. solani at 5th dai. All the tested extracts were found with some antifungal activity at 5% concentration. A. vulgaris can be exploited as a potent alternative to fungicides for controlling A. solani.

Screening of Alternaria Blight of Linseed (Linum usitatissimum) Caused by (Alternaria lini L.) in In-vitro Condition

Linseed (Linum usitatissimum L.) is an important oilseed and fiber crop grown both for its seed as well as fiber.It is widely cultivated in Northern India during the Rabi season. It suffers from a variety of diseases among which Alternaria blight caused by Alternaria lini is one of the most yield limiting factors in India. The efficacy of botanicals (neem, ginger, garlic, bougainvilla and eucalyptus extract), bio-agents (T. harzianum and T. viride) and chemical fungicides (Mancozeb (0.2%), Carbendazim (0.2%), etc. were tested against Alternaria lini in in-vitro conditions. The result of in vitro studies revealed that Neem extract @ 150 ppm significantly reduced the mycelial growth of Alternarialini as 68.6 percent inhibition followed by Garlic bulb extract @ 150 ppm and Ginger rhizome extract@ 150 ppm as 65.45% and 58.65% inhibition respectively. Among fungicide Carbendazim at 500 ppm proved to be most effective in inhibiting mycelial radial growth of pathogen with 100% inhibition over control followed by Mancozeb that showed 93.94% inhibition over control under in-vitro conditions.

ASSESSMENT OF THE ANTIFUNGAL ACTIVITY OF Cymbopogan citratus (Lemon grass) LEAF EXTRACT AGAINST SOME PHYTOPATHOGENS

Since the beginning of mankind, nature has been a source of medicinal agent for thousands of years. A plant pathogen is an infectious organism that is capable of causing disease to plants. This research work was aimed at assessing the antifungal activity of Cymbopogan citratus leaf extract on some phytopathogenic fungi isolated from agricultural soils. Aspergillus niger, Aspergillus tamari and Mucor circinelloides were isolated from an agricultural soil. Aspergillus tamari displayed highest susceptibility to the 50% ethanolic extract of the plant with a mycelial radial growth inhibition measurement of 18.25 ± 0.25 mm while Mucor circinelloides displayed the least susceptibility to the 100% ethanolic extract with a mycelial radial growth inhibition of 45.25 ± 0.25 mm. The results were significantly different from the controls (63.25 ± 0.75 mm, Aspergillus niger; 43.25 ± 1.25 mm, Aspergillus tamari and 63.75 ± 0.75 mm, Mucor circinelloides). In the same vein, the aqueous extract also displayed appreciable antifungal activity. The radial growth inhibition of the aqueous extract ranged from 24.25 ± 0.25 mm (25%, Mucor circinelloides) to 34.50 ± 0.50mm (100%, Aspergillus tamari). These were significantly different from the controls. This Study has shown that lemon grass leaf extract possesses antifungal activities to control phytopathogens, from the result obtained, it can be stated that lemon grass can be exploited as an alternative to chemical fungicides in combating resistance amongst phytopathogens.

Characterization and fitness of Fusarium graminearum mutants resistant to fluazinam

AbstractFusarium head blight (FHB), predominately caused by ascomycete Fusarium graminearum sensu stricto, is a devastating fungal disease of cereal crops worldwide. In this study, baseline sensitivity of F. graminearum s. str. to fluazinam was established using 100 isolates that were collected from Anhui and Jiangsu provinces of China in 2009 and 2018. The EC50 values of fluazinam on mycelial growth inhibition ranged from 0.0211 to 0.1097 μg/mL and the mean EC50 was 0.0601 ± 0.0191 μg/mL, which indicated that fluazinam had a strong inhibitory effect on mycelial growth of F. graminearum s. str. To acquire fluazinam‐resistant (FluR) mutants, one wild‐type strain (PH‐1, with assembled genome) and another four fluazinam‐sensitive (FluS) isolates randomly selected from the above‐mentioned population were domesticated with fluazinam or mutagenized by ultraviolet light in vitro. As a result, 45 FluR mutants were obtained with resistance frequencies of 0.68% (domestication) and 8 in 10−8 (mutagenesis), respectively. Of the 45 FluR mutants, 11 were selected to determine the biological fitness. Based on data of radial mycelial growth, asexual and sexual reproduction, response to environmental stresses, pathogenicity and deoxynivalenol production, all the tested mutants suffered from a fitness penalty. Additionally, slightly positive cross‐resistance was observed between the combination of fluazinam and tebuconazole, pyraclostrobin, or pydiflumetofen, but not phenamacril or carbendazim. Therefore, a low‐to‐moderate risk of development of F. graminearum s. str. resistant to fluazinam was suggested, indicating that fluazinam could be a good alternative fungicide against the FHB in the field.

First report of Alternaria alternata causing leaf yellow spot on Ginger (Zingiber officinale Roscoe) in Laifeng, China.

Ginger (Zingiber officinale Roscoe) is a highly important commercial crop in China, which is widely cultivated for its medicinal and nutritional qualities. Fengtou ginger is a variety mainly grown in Central China. From June to September of 2021, leaf yellow spot symptoms were observed on ginger plants var. Fengtou in commercial fields, localized in Laifeng county (29.37゜N, 109.31゜E), Hubei Province, China. Early symptoms were small yellow spots (approximately 0.2 cm) on leaves, but these spots gradually expanded, and the middle turn brown. The incidence of yellow spot on plants was 15% to 35%. To identify the causal agent of the disease, 15 symptomatic leaves were collected on from plants in the field. From each ginger leaf, small fragments (2 to 4 mm) were cut from the margin of the lesions and surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 s and 60 s, respectively, and rinsed three times with sterile water (Zhong et al. 2022). The disinfected small fragments were placed on Rose Bengal Agar medium at 25 ℃. After 3 to 5 days of incubation, a total of 11 isolates from leaf samples were obtained, of which 8 showed a radial mycelial growth that was grayish and then darkened. Conidiophores were brown and branched. Conidia were multicellular, obclavate to obpyriform within 9.1-22.6 µm (average 14.3 µm) in length and 6.0-13.5 µm (average 7.9 µm) in width (n=30). The isolates were identified as Alternaria sp. according to their morphological characteristics (Simmons 2007). For further molecular identification, genomic DNAs of two representative isolates (isolate 1 and isolate 4) were extracted and amplificated using a set of primers ITS1/ITS4 (White et al. 1990), RPB2-5F/RPB2-7R (Liu et al. 1999) and gpd1/gpd2 (Berbee et al. 1999), for the internal transcribed spacer (ITS)-rDNA region, partial RNA polymerase II largest subunit (RPB2), and Glyceraldehyde 3-phosphate (GADPH), respectively. The sequences were submitted to GenBank with submission Nos. OM701795 and OM701794 for ITS-rDNA; OM864662 and OM864663 for RPB2; OM864664 and OM864665 for the GADPH gene. A BLAST analysis in GenBank showed 100% identity with A. alternata for ITS (GenBank No. MN907440), RPB2 (GenBank No. KP057228) and GADPH (GenBank No. MK637444), respectively. A pathogenicity test was performed on potted healthy plants of ginger var. Fengtou of 2.5-month-old in a greenhouse. A total of five plants were sprayed with a conidial suspension (105 spores/mL) of each isolate on leaves until runoff (3 to 5 ml per plant) occurred. Five plants were sprayed with sterile water. The plants were grown in a greenhouse at 25 ℃. Eight days after inoculation, the symptoms similar to diseased leaves in the field appeared on the inoculated leaves, while the controls remained healthy. The fugus re-isolated from infected tissues was morphologically and molecularly identical to the original isolates of A. alternata, which fulfill the Koch's postulates. To our knowledge, this is the first report of A. alternata causing yellow spot on ginger in China. The work will be beneficial to develop effective management methods for preventing and treating this disease and avoid yield and economic loss of ginger in China.

Hydroxylated Cinnamates Enhance Tomato Resilience to Alternaria alternata, the Causal Agent of Early Blight Disease, and Stimulate Growth and Yield Traits.

The important vegetable crop, tomato, is challenged with numerous abiotic and biotic stressors, particularly the newly emerged fungicide-resistant strains of phytopathogenic fungi such as Alternaria alternata, the causal agent of early blight disease. The current study investigated the potential antifungal activity of four cinnamate derivatives including cinnamic acid, ρ-coumaric acid, caffeic acid, and ferulic acid against A. alternata. Our in vitro findings showed that all tested compounds exhibited dose-dependent fungistatic action against A. alternata when their concentrations were increased from 0.1, 0.3, 0.5, and 0.7, to 0.9 mM, respectively. The high concentration of ferulic acid (0.9 mM) completely inhibited the radial mycelial growth of A. alternata and it was comparable to the positive control (difenoconazole fungicide). Additionally, under greenhouse conditions, foliar application of the four tested cinnamates significantly reduced the severity of early blight disease without any phytotoxicity on treated tomato plants. Moreover, it significantly improved the growth traits (plant height, total leaf area, number of leaves per plant, and shoot fresh weight), total chlorophyll, and yield components (number of flowers per plant, number of fruits per plant, and fruit yield) of treated A. alternata-infected plants. Collectively, our findings suggest that cinnamate derivatives could be good candidates as eco-friendly alternatives to reduce the use of chemical fungicides against A. alternata.

Colletotrichum siamense leaf blight/spot: Characterization of a newly identified disease on Cinnamomum tamala.

Cinnamomum tamala (bay leaf) is widely used for culinary and medicinal purposes in South Asia. A leaf blight/spot disease was first discovered on nearly 90% of C. tamala plants with a mean severity of 48% to 74.4% in Gazipur and Bogura, Bangladesh, in 2019. The present study identified and characterized the causal organism and formulated the optimum growth conditions and effective fungicides for the chemical control of the pathogen. The characteristic symptoms on the infected leaves appeared circular to oval reddish-brown spots with raised margins and often developed in tear-stain patterns. Severe infection of C. tamala sapling resulted in dieback symptoms with leaf defoliation. A fungus with floccose, dense, white colonies with well-differentiated acervuli was isolated from the infected leaves. Combined cultural, morphological, and molecular characteristics identified the pathogen as Colletotrichum siamense. Inculcating healthy leaves and 1-year-old saplings of C. tamala with a conidial suspension of the fungus reproduced the same symptoms observed in the bay leaf orchard. The highest mycelial growth was recorded on V-8 Juice Agar media, while the maximum radial mycelial growth and level of sporulation of the fungus were significantly higher in incubation temperature 30°C. Fungicide trials showed that carbendazim 50 WP, azoxystrobin, mancozeb, and trifloxystrobin, either singly or in combination, successfully reduced fungal mycelial growth in vitro. Therefore, disease management strategies should be opted to halt the further spread of this issue. To our knowledge, this is the first study to document the incidence of Colletotrichum leaf blight on C. tamala in Bangladesh and even in the world.

Fungicidal effects of Commiphora swynnertonii (Burrt.) and Synadenium glaucescens (Pax.) against tomato fusarium wilt disease

Tomato fusarium wilt disease is an important soil-borne disease caused by Fusarium oxysporum f. sp. Lycopersici (FoL) worldwide. The disease causes yield losses of about 90% worldwide. This study aimed to evaluate the extracts of C. swynnertonii (resins) and S. glaucescens (latex, fresh and dry leaves) for their efficacy against FoL. In the laboratory, a 4 × 4 factorial experiment in a Complete Randomized Design (CRD) was carried out to evaluate resins, latex, fresh, and dry leaves each in four concentrations (0.01 g/ml, 0.05 g/ml, 0.1 g/ml and 0.15 g/ml). The negative and positive controls were Sterile Distilled Water (SDW) and a Linkmil 72 WP (Mancozeb 64% + Metalaxyl 8%) respectively. In a screenhouse, resins, latex, and fresh and dry leaves, each at 0.15 g/ml were applied on pre-inoculated tomato plants to manage TFW disease. The experiment was laid out in a Randomized Complete Block Design (RCBD) with four replications. The negative and positive controls were the untreated soil and soil treated with Linkmil 72 WP respectively. The differences between extracts in the inhibition of radial mycelial growth of the pathogen were highly significant (p = 0.000). The efficacy of the plant extracts against in vitro growth of FoL was significantly dependent on the application dose. The inhibition of mycelial growth caused by latex and dry leaves was higher than that of Linkmil 72 WP (23.58%) and SDW (0%) by 41% and 65% respectively. Findings show that there was a TFW disease reduction of 72.92% 68.75% and 56.25% in plants treated with dry leaves, the latex of S. glaucescens, and resin of C. swynnertonii in that order. Plant extracts had significant effects (p = 0.000) on plant growth. The plants treated with dried leaf powder attained the highest height, the number of branches/plant, leaves/plant, and leaf area of 85.85 cm, 19.25,99.5 and 59.39 respectively. The findings benchmark the fungicidal potential of C. swynnertonii and S. glaucescens.

Evaluation of antifungal efficacy of chitosan against Aspergillus fumigatus of stored rice (Oryza sativa)

Contamination of stored rice with fungal pathogens results in rice of poor quality and economic value, and may also have harmful effects on human and animal health. This study aimed at evaluating the antifungal efficacy of chitosan against Aspergillus fumigatus of stored rice (Oryza sativa). Four forms of chitosan were used in this study viz; Purchased Low, Medium and high molecular weight chitosan and chitosan synthesized from Crab Shell using deproteinization, demineralization, decolouration and deacetylation. Degree of deacetylation of the synthesized chitosan was determined using Fourier transform infrared (FTIR) analysis. The in vitro antifungal activity of all forms of chitosan were determined using food poisoning method against Aspergillus fumigatus isolated from stored rice seeds using agar plate methods. The percentage inhibition of mycelial radial growth Aspergillus fumigatus by the different forms of chitosan was determined. Fourier Transfrom InfraRed Spectra of synthesized chitosan showed major absorption bands from 3444.72, 2966.17, 2512.60, 2144.84, 1429.74, 1258.12, 1160.05, 1025.2, 869.92, 710.50, 608.40 to 559.36. Absorption peak at 559 was assigned to glucopyranose ring in the chitosan matrix. Degree of deacetylation of synthesized chitosan was at 98.6% degree. Highest mycelia radial growth of 8.00 cm was recorded in control, while 2.00, 0.00, 5.23, and 1.33cm were recorded in 2.0% concentration of High Molecular Weight Chitosan (HMWC), Medium Molecular Weight Chitosan (MMWC), Low Molecular Weight Chitosan (LMWC) and Chitosan synthesized from Crab shell (CSCS) treatment respectively. The result of the percentage inhibition reveals that A. fumigatus had 100% inhibition in 1.5% HMWC and 2.0% MMWC while 85% inhibition in 2.0% CSCS which were significantly different from 2.0% LMWC with 36.5% inhibitions. Results obtained from this study has shown the effectiveness of chitosan as an effective antifungal agent which can improve and maintain the quality of stored rice and ensure a safer environment due to its nontoxic and environmental friendly properties.

Salmon oyster mushroom: growth characteristics and protease production on a laboratory scale

Pleurotus have an easy cultivation and are excellent sources of proteolytic enzymes. The aimed was evaluate the mycelial growth and extracellular protease activity of Pleurotus ostreatoroseus. The mushroom was grown on potato dextrose agar (BDA) with yeast extract (YE) 0.5% (w/v). The radial mycelial growth velocity (RCV) and mycelial density occurred on different media containing 0.5% (w/v) YE: Potato Dextrose agar (BDA), GYP agar (glucose, yeast extract and peptone), malt extract agar (MEA), purple yam extract agar (EIR), torn yam extract agar (CEIN), aria extract agar (EA). Proteolytic activity was determined by the gelose block method. In mycelial growth (VCM) is used: cupuaçu exocarp (CC), açaí (Sac), pineapple (CsAb) and sawdust (SER), supplemented with rice bran (FA) or wheat bran (FT) were used. Proteases were extracted in sterile distilled water under 180 rpm agitation at 30 °C. Significant RCV was observed in MEA+YE (12.32 ± 0.10 mm/day). However, GYP agar showed strong mycelial density. Significant substrate mixture with strong mycelial density occurred on Sac+FA (0.61 ± 0.09 cm/day). The tested media were efficient in the production of extracellular proteases by this mushroom.

Efficacy of Lactic Acid Bacteria as a Biocontrol Agent against Anthracnose (Persea americana Miller) Decay in Avocado (Persea americana) cv Fuerte Fruit

Anthracnose disease is still a threat to avocado fruit quality, and the use of fungicide (Plochloraz®) for its control has generated safety concerns that necessitate the search for alternatives. Therefore, the efficiency of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol agents against Colletotrichum gloeosporioides was investigated in this study. Weissella cibaria 21 (LAB 21), Leuconostoc pseudomesenteroides 56 (LAB 56), Weissella confusa 17 (LAB 17), Lactiplantibacillus plantarum 75 (LAB 75), and Lactiplantibacillus plantarum 171 (LAB 171) were evaluated in vitro as potential biocontrol agents to replace the Prochloraz® that is currently used in susceptible avocado (Persea americana Miller) Fuerte fruit. To confirm the biocontrol activity of the selected LAB strains, the antagonistic growth, spore germination, LAB recovery, nutrient competition, acid tolerance, and biofilm formation were assessed. In fruit treated with a LAB cell suspension, curatively inoculated with C. gloeosporioides, or naturally infected avocado cv Fuerte fruit, the epicatechin content and expression of defense-related genes (PAL, LOX, AVFADl 2–3, AVFAEL, and FLS) were compared with Prochloraz® and sterile water (control) treatments. With LAB 56, LAB 75, and LAB 21, significant inhibition of radial mycelial growth (MGI) (>90%) and spore germination (100%) was observed similar to those due to Prochloraz®. The MGI increased with a reduction in nutrient concentration. LAB strains reduced anthracnose disease incidence and severity compared with Prochloraz® and were the highest in LAB 21 and LAB 56. The LAB 21 and LAB 56 strains produced strong biofilms against C. gloeosporioides. In contrast to LAB 56, the control, and Prochloraz®, and LAB 21 had the highest epicatechin content (406 mg/g) and upregulated the PAL, AVFADl 2–3, AVFAEl, and FLS genes, thereby reducing the incidence of anthracnose in avocado fruit. As a result, LAB 21 suspensions can be used as an alternative to Prochloraz® in the control of anthracnose disease.

Nonlinear regression application in Aspergillus flavus radial mycelial growth inhibition by essential oils of Piper guineense Schum and Thonn., Zingiber officinale roscoe and Monodora myristica (Gaertn) Dunal

Nonlinear regression application in Aspergillus flavus radial mycelial growth inhibition by essential oils of Piper guineense Schum and Thonn., Zingiber officinale roscoe and Monodora myristica (Gaertn) Dunal

Isolation, Evaluation and Characterization of Indigenous Trichoderma spp. for the Management of Wilt of Chickpea Caused by Fusarium oxysporum f. sp. ciceris

Background: Fusarium oxysporum f. sp. ciceris causing chickpea wilt, a significant soil-borne disease that causes severe crop losses. Trichoderma spp. is a diverse fungal bio-control agent with the ability to limit plant disease growth through a variety of ways. The goal of this work is to assess the efficiency of indigenous Trichoderma spp. isolated from chickpea rhizosphere from different North Eastern districts of Karnataka against the wilt pathogen in vitro, as well as to investigate the cultural and morphological aspects of isolates. Methods: Dual culture approach was used to investigate the antagonistic potential of Trichoderma isolates and inverted plate technique was used to examine the synthesis of volatile compounds from Trichoderma spp. The isolates were cultured on potato dextrose agar medium for cultural characterization. Under a microscope, morphological characters were observed. Result: Twenty Trichoderma isolates were reported to be effective against F. oxysporum f. sp. ciceris, preventing mycelial growth by 48.52 to 91.85%. All the isolates produced significant amount of volatile compounds that inhibited F. oxysporum f. sp. ciceris growth by 2.59 to 72.22%. At 72 hours after incubation, the isolates had different radial mycelium growth and formed fluffy and elevated colony growth, with colony margins ranging from smooth to wavy.