Percentage Inhibition Of Mycelial Growth Research Articles

Bio-efficacy of Kresoxim Methyl 44.3 % SC Against Late Blight of Tomato under In vitro Condition

Tomato (Lycopersicon esculentum L.) is one of the most important vegetable crops grown throughout the globe for its nutritional and antioxidant properties. In recent years, the production of this crop is hindered by various pests and diseases. Late blight is one of the most common and devastating disease of tomato crop which is caused by the fungus Phytophthora infestans. In order to manage this disease, an experiment was conducted in the laboratory of IPFT, Gurgaon. For this, different concentration of Kresoxim methyl 44.3 % SC at 80 ppm, 40 ppm, 20 ppm, 10 ppm, 5 ppm and 2.5 ppm were evaluated against late blight of tomato under in vitro using food poison technique. Observations on radial growth of the pathogen recorded after 3, 7 and 10 days of transferring culture in media showed that the Potato Dextrose Agar (PDA) plates with 80 ppm Kresoxim methyl 44.3 % SC recorded minimum radial growth of pathogen (1.53, 3.13 and 2.73 cm) followed by 40 ppm (1.69, 3.50 and 3.10 cm) after 3, 7 and 10 days of treatment application. Moreover, Kresoxim methyl 44.3 % SC at 80, 40, 20 and 10 ppm were effective over control as they exhibit more than 50 % reduction in radial growth over control. The percent inhibition of mycelial growth over control was highest (67.82 %) in PDA plates consisting of 80 ppm Kresoxim methyl 44.3 % SC followed by 40 ppm (62.96 %) after 10 days of transferring culture in media. The treatment with 5 ppm and 2 ppm recorded less than 50 % reduction of pathogen growth.

Inhibition of the Growth of Four Phytopathogenic Fungi by Eucalyptus Wood Vinegar

Purpose: The objective of this work aimed to assess the wood vinegar (WV) from the carbonization of Eucalyptus wood in the inhibition in vitro of Fusarium sp., Ganoderma sp., Macrophomina sp., and Sclerotium rolfsii. Method: WV was added to a culture medium and poured onto Petri dishes. After, the fungi were picked up in 1-mm disks and placed in the center of each Petri dish. The experimental design had five treatments, T1, T2, T3, T4, and T5, with crescent concentrations of WV, respectively, 0 (control), 5, 10, 15, and 20 mL L-1. The variables evaluated were fungal growth, mycelial growth rate index, and percentage of mycelial growth inhibition. Results and Discussion: A gradual decrease in the mycelial growth, in the mycelial growth rate index, and an increase in the percentage of mycelial growth inhibition were determined for all assessed fungi in the concentration of 20 mL L-1 of WV. Hence, the conclusion was that eucalyptus WV presented fungi-toxic properties over the assessed fungi and the product can be considered as an alternative for the chemical control of the incidence of these pathogens in crops and forest plantations. Research Implications: The use of natural products with fungi toxic properties is becoming important for the control of pathogens that attack crops and forest plantations due to the harmful effects of the conventional fungicides on living organisms and the environment. The search for efficient alternative products is therefore a goal to be reached in the field of phytopathology. Originality/ Value: The use of natural products with fungitoxic properties has been gaining ground in the control of pathogens affecting agricultural and forestry crops. This intensifies the search for natural products that are efficient in the biocontrol of phytopathologies.

<em>In Vitro</em> antifungal activity of selected plant extracts against mango stem end rot pathogen: <em>Lasiodiplodia theobromae</em>

Phytopathogens are primarily controlled through the application of synthetic products, which harm human and environmental health. The use of plant-derived extracts as ecofriendly bioagents has become increasingly popular due to the biologically active compounds present in the plants. Thus, a study was conducted to determine the antifungal activity of the ethanol and acetone leaf extracts of Argyreia pomacea, Coccinia grandis, Erythrina subumbrans, and Gymnema sylvestre against the causal pathogen of mango stem-end rot. Pathogen was isolated from diseased mangoes and identified as Lasiodiplodia theobromae. The pathogenicity of the isolated L. theobromae was confirmed on healthy samples of mangoes. The antifungal activity of leaf extracts was determined by the food poison technique. The leaf extracts were tested at different concentrations of 50, 25, and 12.5 mg/ml. Results indicated that the ethanol extract of E. subumbrans (29.21 ± 0.65 %) at the concentration of 50 mg/ml showed the highest percentage of mycelial growth inhibition followed by the acetone extract of G. sylvestre (28.97 ± 0.79 %) at the concentration of 25 mg/ml against the L. theobromae. The percentage of mycelial growth inhibition was significantly different among all treatments (P < 0.05). This might be due to the different kinds of phytochemicals in the plant leaves. Further studies are required to isolate and identify the specific bioactive compounds from the leaves, responsible for these antifungal activities.

Chitosan: Biocontrol agent of Fusarium oxysporum in tomato fruit (Solanum lycopersicum L.)

Synthetic fungicides have experienced a significant increase in recent years, necessitating the search for more sustainable and environmentally friendly alternatives. In this regard, chitosan has emerged as an option to reduce reliance on these products. This study evaluated the effect of chitosan as a biocontrol agent against Fusarium oxysporum in tomato fruits. A fully randomized experimental design incorporating 6 treatments was employed, consisting of four chitosan treatments (0.5, 1, 2, and 3 g L-1), a negative control involving the application of a synthetic fungicide, and a positive control inoculated with F. oxysporum. Samples were taken from infected tomato fruits. The F4 isolate of Fusarium sp. was identified as F. oxysporum, and demonstrated the highest level of virulence. Among the four chitosan treatments, the 3 g L-1 treatment showed the highest a percentage of mycelial growth inhibition (PMGI) at 79.92% and the greatest reduction in biomass at 0.65 g, which did not differ significantly from the synthetic fungicide. Regarding disease severity and incidence, there were significant variations among each of the chitosan treatments, with the highest results obtained with the 2 and 3 g L-1 treatments. All chitosan treatments reduced disease severity in tomato fruits. Applying chitosan on fruits of the tomato plant presents an alternative for diminishing reliance on synthetic fungicides.

KARAKTERISASI MORFOLOGI DAN UJI ANTIFUNGI ISOLAT JAMUR Trichoderma spp. DARI TANAH GAMBUT TERHADAP PATOGEN PADA JARAK KEPYAR (Ricinus communis L.)

Castor oil (Ricinus communis L.) is an oil producing commodities that plays a role in meeting industrial and economic needs. Infection with the pathogen fungi caused a decrease in the production of castor oil. Biological control using Trichoderma spp. has been widely used. Trichoderma spp. known as one of the benefical biofungicide because it has high antagonistic properties inhibiting the growth pathogenic fungi. The purpose of this study was to obtain isolates and characters as well antifungal test for Trichoderma spp. isolated from peat soil to control pathogen Aspergillus sp. on castor been (Ricinus communis L.). Trichoderma spp. isolated from peat soil in Meranti Islands, Riau. The antagonistic activity the isolates against pathogen Aspergillus sp. was studied in vitro using dual culture and in vivo assay. In this study, six isolates of Trichoderma spp have isolated. Trichoderma sp. GBA5 has the highest growth rate on PDA and TSM medium. Trichoderma sp. GBA3 and Trichoderma sp. GBA4 were most effective in percentage inhibition of mycelial growth of test pathogen i.e 84,55% and 83,71% respectively. In in vivo assay, only Trichoderma sp. GBA5 inhibited pathogen with the percent infected castor capsule was 51.66%.

Exploring fungal endophytes as biocontrol agents against rice blast disease

The rice blast disease caused by <i>Pyricularia oryzae</i> Cavara is among the most severe plant diseases in the world. The utilization of natural antagonists, such as fungal endophytes, can be a good method to control the spread of this disease. In the present study, 68 fungal isolates were obtained from 160 rice samples collected in Guilan province fields, Iran. Morphological and molecular characteristics were used for the identification of these fungi. According to the results, the fungal isolates were <i>Alternaria citri</i> (Penz.) Mussat, <i>Alternaria infectoria</i> Simmons, <i>Aspergillus fumigatus</i> Fresen, <i>Fusarium verticillioides</i> (Sacc.) Nirenberg, <i>Trichoderma harzianum</i> Rifai, <i>Trichoderma virens</i> (Mill., Giddens & Foster) Arx, <i>Trichoderma viride</i> Pers., <i>Ulocladium consortiale</i> (Thum) Simmons, and <i>Pyricularia oryzae</i> . Eight isolates that did not cause any plant disease were selected for biocontrol studies <i>in vitro</i> . The dual culture, culture filtrate, slide culture, and volatile metabolites methods were used in search of natural endophytic antagonists of <i>Pyricularia oryzae</i>. It was found that <i>T. harzianum, T. virens, T. viride, A. fumigatus</i>, and <i>A. citri</i> isolates caused the highest percentage of mycelial growth inhibition of <i>P. oryzae in vitro</i>. In the greenhouse experiments, all of the studied isolates reduced the <i>P. oryzae</i> disease rating, with <i>T. harzianum</i> isolate being the most effective antagonist (27.36% reduction in the disease rating), followed by <i>T. virens, T. viride</i>, and <i>A. fumigatus</i> (20.75%, 17.92%, and 16.98%, respectively). Furthermore, in greenhouse conditions, these antagonistic fungi increased the height, fresh weight, and dry weight of plants. The results of this research showed that there are various fungi in the natural flora of rice plants that possess potential biological properties against rice blast disease that can be implemented into practice.

Enhanced white rot control in garlic bulbil using organic-inorganic hybrid materials as coating membranes.

Organic-inorganic hybrid materials have a range of applications due to their unique properties. Their application in agriculture brings alternatives for the controlled release of nutrients in the soil, the seed coating, the transport of herbicides, and the treatment of plant diseases. The present study aimed to investigate the use of fungicides incorporated into hybrid membranes formed by synthetic hectorite (LAPONITE®) and polymers in the pre-treatment of garlic bulbils exposed to the pathogen Stromatinia cepivora, which causes white rot. The coatings were selected by a germination test, based on the bulbil sprouting index, and by a mycelial growth inhibition test, based on the percentage of mycelial growth inhibition. The chosen membranes were used to coat the bulbils for bioassays conducted in a biochemical oxygen demand incubator at 17 °C. The coated bulbils were planted in soil samples containing three different densities of Stromatinia cepivora: 0.1 g, 1.0 g, and 10 g of sclerotium per L of soil. Membranes containing 2% carboxymethyl cellulose and 2% LAPONITE® incorporated with (i) the fungicide tebuconazole (36 mg L-1) and (ii) the combination of the actives tebuconazole (36 mg L-1) and triadimenol (62 mg L-1) showed the total rate of sprouting and null indices of incidence of symptoms and mortality in its repetitions. The hybrid membranes were characterized employing several techniques, including X-ray diffraction, infrared and Raman spectroscopy, thermogravimetric analysis and differential scanning calorimetry coupled to mass spectrometry, and optical microscopy. Characterization data confirmed the presence of fungicides incorporated into the membranes. Some concentrations of fungicides were low enough not to be detected in all analyses performed, although they guaranteed a protective character to the bulbils about the fungus S. cepivora present in the soil, with a possibility of antifungal pre-treatment with a potential reduction in the concentration used.

CHITOSAN INHIBITS THE <i>IN VITRO</i> DEVELOPMENT OF <i>Colletotrichum</i> SP. FROM BANANA (<i>Musa x paradisiaca</i> L.) FRUITS

The banano (Musa x paradisiaca L.) is a tropical fruit, susceptible to infection by Colletotrichum sp. Fungicides are the most typical approach for controlling postharvest infections. Concerns regarding its negative impact on human health and the environment have prompted the quest for alternate remedies. Because of its antimicrobial activity, chitosan is an environmentally friendly alternative. This study aimed to determine the influence of chitosan on the in vitro development of Colletotrichum sp. isolated from banana fruits. Inhibition mycelial growth, spore concentration and spore germination were evaluated in three chitosan concentrations, 0.5 %, 1.0 % and 1.5 %. Optical, fluorescence, and scanning electron microscopy were used to examine the impact of chitosan on spore growth and morphology. We observed that chitosan solutions inhibited Colletotrichum species in vitro. Chitosan at 1.5 % significantly decreased the percentage of mycelial growth inhibition and spore concentration in comparison with the control. Compared to the control, a concentration of 1.5 % chitosan considerably decreased the mycelial growth and spore concentration. In addition, a complete inhibition of spore germination and a low mycelium content was observed with 1.0% and 1.5% chitosan, controlling the in vitro development of Colletotrichum sp. in banana fruits.

Biogenic Synthesis, Characterization, and Antifungal Activity Studies of Copper Oxide Nanoparticles Using Aqueous Extract of Moringa oleifera Leaves

AbstractThe present study reports the green synthesis of cupric oxide nanoparticles (CuO NPs) by an aqueous leaf extract of Moringa oleifera and the antifungal activity assessment of CuO NPs against the phytopathogenic fungi Aspergillus flavus and Aspergillus niger. The CuO NPs showed variable fungitoxic effects against A. flavus and A. niger. At higher doses (1 mg/mL), 83.51 % of mycelial inhibition was found against A. flavus, but 43.51 % was found against A. niger. The percentage inhibition of mycelial growth was found to be dose dependent. The cell viability analysis was carried out to reveal the mechanism of the fungitoxic effect of synthesized NPs and it was revealed that the CuO NPs caused oxidative stress associated with increased ROS production, leading to fungal cell death. The synthesized CuO NPs showed single phase cupric oxide with a monoclinic structure and highly uniform in size (3–5 nm). As the synthesized CuO NPs showed good stability under open atmospheric conditions and a fungitoxicity effect against A. flavus, they may be used to control fungal diseases in an eco‐friendly manner.

Efficacy of fungicides against Rhizoctonia solani (J. G. Kuhn) causing root rot of french bean

The present in vitro study was carried out at the Department of Plant Pathology, University of Agricultural Sciences, Dharwad, Karnataka, India to evaluate the efficacy of various fungicides against Rhizoctonia solani (J. G. Kuhn) causing root rot of french bean using poisoned food technique. Among the contact fungicides tested, captan (70.37 %) and chlorothalonil (69.63 %) recorded maximum percent inhibition of mycelial growth and significantly superior over all other treatments. Carbendazim, difenoconazole, hexaconazole, propiconazole and tebuconazole (systemic fungicides) recorded cent per cent inhibition of mycelial growth of Rhizoctonia solani. Cent percent mycelial inhibition was recorded in all the combi product fungicides viz., (carbendazim + mancozeb), (trifloxystrobin + tebuconazole), (tricyclazole + mancozeb), (captan 70 % + hexaconazole 5 %) and (carboxin + thiram) at all the concentrations.

Plant Extracts Control In Vitro Growth of Disease-Causing Fungi in Chayote.

The use of agrochemicals has caused environmental problems and toxicity to humans, so natural alternatives for disease control during harvest and postharvest have been evaluated. The aim of this study was to evaluate cinnamon essential oil, neem oil, and black sapote fruit extract for in vitro inhibition of fungi isolated from chayote fruit. The extracts were applied at 300, 350, and 400 ppm in Petri dishes and the mycelial growth of Fusarium oxysporum, Fusarium solani, Goetrichum sp., and Phytophthora capsici was evaluated for 7 days, and the percentage of mycelial growth inhibition per day was calculated. Cinnamon oil showed a fungicidal effect at all concentrations. Neem oil at 400 ppm showed a 42.3% reduction in the growth of F. solani and 27.8% reduction in the growth of F. oxysporum, while at 350 ppm it inhibited the mycelial growth of Phytophthora capsici by 53.3% and of Goetrichum sp. by 20.9%; finally, the black sapote extract at 400 ppm inhibited 21.9-28.6% of the growth of all fungi. The growth of postharvest fungi on chayote fruit could be prevented or reduced by applying the plant extracts evaluated at adequate concentrations.

Evaluation of Fungicides, Phytoextracts and Germplasm Screening Against Lasiodiplodia Theobromae Causing Fruit Rot of Jackfruit

The current study was carried out to evaluate the efficacy of different fungicides against the Lasiodiplodia theobromae under laboratory conditions, which demonstrated that all of the fungicides inhibited the pathogen significantly. Carbendazim 50% WP (0.1%) and combi product Carbendazim 12% + Mancozeb 63% WP (0.15%) were the most effective fungicide which showed complete inhibition of the mycelial growth of the pathogen followed by Fludioxanil 230 SC (0.15%), Difenoconazole 25% EC (0.1%), combination fungicide Tebuconazole 50%+ Trifloxystrobin 25% WG (0.1%), Mancozeb 75% WP (0.2%) and Copper oxychloride 50% WP (0.25%), respectively over control. The mean percent inhibition of mycelial growth was recorded in adulsa leaf extract (22.03%), eucalyptus leaf extract (19.81%), tulsi leaf extract (19.08%) and garlic clove extract (18.89%) of the nine plant extracts. Among the fifteen germplasm and three varieties of jackfruit tested for resistance to fruit rot in the laboratory, the variety Konkan prolific was found to be resistant to Lasiodiplodia fruit rot disease. Two varieties/germplasm were moderately resistant to Lasiodiplodia fruit rot, while three germplasm were moderatelysusceptible.

Characterization of Volatile Organic Compounds Produced by Bacillus siamensis YJ15 and Their Antifungal Activity Against Botrytis cinerea.

To develop an effective and environmentally safe strategy to control postharvest gray mold caused by Botrytis cinerea, Bacillus siamensis strain YJ15 isolated from blueberry was used to test the biocontrol potential. It is interesting to find that the volatile organic compounds (VOCs) emitted from strain YJ15 exhibited significant antifungal activity against Botrytis cinerea as well as 11 other plant-pathogenic fungi, with a percentage of mycelial growth inhibition from 74.96 to 92.81%. Additionally, VOCs from strain YJ15 could reduce significantly the disease incidence and lesion diameter with the increasing of fermentation time, indicating great biocontrol potential for controlling blueberry postharvest gray mold. Furthermore, the VOCs were collected by using headspace solid-phase microextraction fiber, and the composition of VOCs was further revealed by using gas chromatography coupled with quadruple mass spectrometry. In total, 24 kinds of VOCs, including 5 alkanes, 2 aldehydes, 3 ketones, 5 alcohols, 1 alkene, 5 acids and esters, 2aromatic compounds, and 1 sulfur compound, were emitted at 1, 3, 5, and 7 days after inoculation. Among these VOCs, eight antifungal VOCs could inhibit mycelial growth of B. cinerea. It is important to highlight that, although 1-butanol and 3-methyl-1-butanol were the most abundant compounds, 2-ethylhexanol, 1-heptanol, and 1,3-xylene have proved to be more toxic to B. cinerea than 3-methyl-1-butanol, propanethioic acid, 2,2-dimethyl-, ethyl 2-methylbutyrate, 2-heptanone, and 1-butanol, which provide new, promising biofumigants for the control of postharvest gray mold caused by B. cinerea.

Essential oil form clove (Syzygium aromaticum) to control Sclerotium rolfsii in vitro

Essential oils can inhibit growth of several phytopathogenic fungi of agricultural concern, such as Sclerotium spp. which causes root and collar rots, hampering the absorption of water and nutrients. Natural oils have short persistence in the environment and low toxicity, comprising compounds safer than conventional agrochemicals. Within the context of integrated management of diseases, essential oils may benefit the health of farmers, consumers and the environment. This study evaluated the in vitro inhibitory effect of clove (Syzygium aromaticum) essential oil on the mycelial growth of Sclerotium rolfsii. The experimental design was completely randomized, with 7 treatments (5 oil concentrations, 1 negative control, and 1 positive control) and five replications, with the experimental unit constituted by a Petri dish. The treatments consisted of different oil concentrations (0.0125; 0.025; 0.05; 0.1 and 0.2%) of clove essential oil, a negative control (0.0%) and a positive control, fungicide Tiram (1 mL L-1). The essential oil and the fungicide Tiram were merged into the synthetic Potato-Dextrose-Agar (PDA) culture medium. The plates were inoculated with the pathogen S. rolfsii and incubated for seven days at 25 ± 2 °C. We compared the treatments through the percentage of mycelial growth inhibition (PIC) and the mycelial growth velocity index (IVCM). Increasing oil concentration significantly reduced the mycelial growth of S. rolfsii and paralyzed mycelial growth at 0.1% concentration. The effect of clove essential oil was similar to the commercial fungicide.

Inhibition and stimulation of mycelial growth of Moniliophthora roreri by flutolanil in populations of Ecuador

Frosty pod rot (FPR) of cacao is caused by Moniliophthora roreri (MR). Effective management must include chemical or biological control, in addition to agronomic tactics. Flutolanil has been effective in controlling FPR. The objective of this research was to determine the response to flutolanil of MR isolates from the Amazon and Coast regions of Ecuador. Percentage of mycelial growth inhibition (PGI), and medium inhibitory concentration (IC50) against three concentrations of the fungicide were determined. One µg mL-1 of flutolanil in the culture medium inhibited completely the growth of the 76 MR isolates. At 0.1 μg mL-1, 74/76 were inhibited between 70-97 % compared to the control. Conversely, at the lower concentrations (0.01-0.001 μg mL-1) the results of inhibition were only of 22 % and 47 %, respectively. Four groups were identified: one included the most sensitive (66/76) to different degrees, and three groups representing 10 isolates that were stimulated at low concentrations of flutolanil. IC50 values were low, indicating very high sensitivity in the MR population. IC50max were 0.1342 and 0.1457 in two isolates from the Coast and the Amazon regions, respectively. Isolates from the Coast were significantly less sensitive to flutolanil than those from the Amazon ( IC50 = 0.046 ± 0.03 and IC50 = 0.030 ± 0.02, respectively), however, the differences were minimal. There were no significant differences when comparing the provinces. The most stimulated isolates were found in the provinces of Orellana and Los Ríos. It is concluded that flutolanil seems effective against the causal agent of FPR in Ecuador, both Coast and Amazon regions.

English

The damaging potential of Alternaria alternata on different mungbean genotypes was accessed and its management was done under in vitro and in vivo conditions through suitable fungicides. Seeds of fifty different mungbean genotypes were sown in lines. There were fifteen replications for each line. The data on disease incidence and percent disease intensity were accessed on all the genotypes. Infection was observed on all genotypes, none of them were found to be immune. Fourteen lines were found to be the most susceptible (14114, 14117, 14128, 14198, 14203, 14205, 14250, 14265, 14266, 14295, 14305, 14306, 14368, 14438). Infection was observed on all genotypes, none of them were found to be immune. The maximum PDI (Percent Disease Intensity) was recorded 35.30% while minimum was 2.43%. For detached leaf assay, the conidial suspension of 105 conidia/mLwas prepared and sprayed on detached leaves. The results revealed that maximum infection percentage was observed in 14306, 14198 genotypes while minimum was observed in 14128, 14203. The lesion area was found to be maximum in 14306, 14198 (0.23, 0.22) while minimum in 14128 (0.12) respectively. For management experiments, different fungicides; Propiconazole (Tilt), Propineb (Antracol), Difenconazole (Score), Thiophanate methyl (Topsin M), Mancozeb (Dithane M45) were tested under in vitro and in vivo conditions. Significant decrease in mycelial growth with the increase in concentration of fungicides was observed. Percent inhibition of mycelial growth was maximum in Propiconazole at its highest concentration (1000 ppm) under in vitro conditions. A significant decline in disease incidence was observed as compared to control treatment. The minimum percent disease incidence was recorded in Propiconazole (10.34) with PDC (67.31) while the maximum percent disease incidence was observed in Thiophanate methyl (25.46). So, Propiconazole could be used successfully for the management of A. alternata under field conditions.

Antagonismo de Trichoderma harzianum y Trichoderma viride sobre aislados de Fusarium spp. procedentes de Nicotiana tabacum

Tobacco production is a key line in the Cuban economy and generates the largest income in the agricultural sector. Within phytopathogens affecting this plant, Fusarium spp., constitutes a pest of interest, due to vascular involvements that cause deterioration of the commercial value of the leaf. Therefore, the research was carried out with the aim of determining the antagonistic activity in vitro of native strains of Trichoderma harzianum and T. viride on isolates of Fusarium oxysporum and F. phyllophylum, from Nicotiana tabacum L. in Granma province, Cuba. The work was carried out at the Laboratory of Agricultural Microbiology, University of Granma. Half dextrose potato agar was prepared to establish the dual crops of Trichoderma spp. vs. Fusarium spp. Once the treatments were established and the incubation time had elapsed, the percentage inhibition of mycelial growth, antagonistic capacity and mycoparasitic activity was determined. A fully randomized design with four replicas per treatment was used and a two factorial ANOVA and Tukey test (p≤0.05) were used for statistical processing. It was shown that the strains of Trichoderma spp., recorded intermediate values of phytopathogenic inhibition, the competitiveness of the antagonist was mostly located in class two of the Bell scale and it was found that penetration, winding, vacuolization, deformation and granulation constitute the main forms of mycoparasitism. Which points to this biocontrol method as an alternative to consider for the management of Fusarium spp., in tobacco agroecosystems.

Efficiency of essential oils to control Colletotrichum theobromicola in vitro

Essential oils promote the inhibitory control of several fungi, including those within the genus Colletotrichum, the causal agent of Anthracnose, a disease which may occur at any stage of development in various crops, reducing up to 70% of crop production in some cases. Thus, the use of alternative products constitutes an important strategy for the integrated management, promoting less persistent molecules in the environment and lower toxicity rates, providing health benefits to producers and consumers of agricultural products. In this context, the present study evaluated the in vitro fungitoxic effect of essential oils from Java citronella (Cymbopogon winterianus), clove (Syzygium aromaticum), eucalyptus (Eucalyptus globulus) and rose pepper (Schinus terebinthifolius) on the mycelial growth of Colletotrichum theobromicola. The experiment was performed under completely randomized design, in a 4x5 factorial scheme (4 essential oils x 5 concentrations), with five replications, and the experimental unit consisting of a Petri dish. The treatments were generated by combining the concentrations (0, 5, 10, 15, 25 and 50 μL mL-1) of essential oils (citronella, clove, eucalyptus and rose pepper). The plates were inoculated with the pathogen C. theobromicola and incubated for seven days at 25 ± 2 °C. To verify the difference between treatments, the percentage of mycelial growth inhibition (PGI) was estimated. The mycelial growth of C. theobromicola was significantly reduced with increasing concentrations of essential oils. At a concentration of 50 μL mL-1, the essential oil from S. terebinthifolius showed the best result inhibiting 54.57% of mycelial growth, followed by the oil from S. aromaticum (49.26%), C. winterianus (23.70%) and E. globulus (17.90%). All the studied oils showed antifungal activity.

In vitro Evaluation of Leaf Extracts against Macrophomina phaseolina in Mulberry through Poisoned Food Technique

Mulberry (Morus alba L.) is a valuable tree of immense importance in silk industry due to its foliage, which constitute the chief food for silkworms (Bombyx mori L.) the source of fabulous silk. One of the major constraints in the cultivation and production of quality mulberry leaf is the attack of pests and diseases. Among the several diseases, root rot caused by Macrophomina phaseolina (Tassi) Goid is becoming a serious problem in many mulberry growing areas of south India. The root rot infected root samples were collected from the field and used for isolation of the pathogen. Cold water extracts of 10 plants species were screened against the mulberry root rot pathogen M. phaseolina. Among them, two plants extracts viz., curry leaf (Murraya koenigii L.) and Marunthukoorkan (Coleus forskohlii) showed the 67.77 percent and 61.10 percent inhibition of mycelial growth over control respectively. Similarly the sclerotial production showed 87.33 percent and 82.15 percent inhibition over control respectively.

Novel Prosopis juliflora leaf ethanolic extract as natural antimicrobial agent against food spoiling microorganisms

Fresh produces spoilage is a worldwide concern that accompany the global increase in food demand. Adverse human health and environmental effects of commercial spoilage control agents are major public concern. In this study, Prosopis juliflora leaves and fruit extracts had their antimicrobial activities evaluated against the growth of selected bacteria and yeast, and against mycelial growth and conidial germination of selected mycotoxins-producing fungi. P. juliflora water-soluble leaf ethanolic (PJ-WS-LE) extract with its novel extraction method showed the strongest antibacterial activity. Antimicrobial tests showed total inhibition of Botrytis cinerea, Alternaria alternata, Bacillus subtilis, Staphylococcus aureus and Candida albicans with MICs ranging between 0.125 and 1 mg/ml. Percent inhibition of mycelial growth (PIMG) of the extract was also determined against seven other fungal strains with highest value against Geotrichum candidum (66.2%). Even the least affected fungal strain showed alterations in their hyphae and spores exposed to PJ-WS-LE extract when observed using scanning electron microscope (SEM), alterations include exfoliated flakes, pores, vacuolation and applanation. Small-scale fruit bioassays controlled experiment showed high efficacy of the extract in protecting inoculated cherry tomato samples from B. cinerea and A. alternata infections. In conclusion, PJ-WS-LE extract is a feasible, natural antifungal agent that can replace common anti-spoiling chemicals.