scholarly journals Assessment of Plant Extracts and their In vitro Efficacy against Potato Early Blight Incited by Alternaria solani

2021 ◽  
Vol 15 (3) ◽  
pp. 1591-1601
Author(s):  
Sumit Kumar ◽  
Ram Chandra ◽  
Lopamudra Behera

Botanicals obtained from the plants are well known for the suppression of inimical plant pathogens. The present study explores the efficacy of five locally available plant extracts for their antifungal activity against the early blight of potato incited by Alternaria solani. The extracts include Datura stramonium, Allium sativum, Azadirachta indica, Eucalyptus globulus, and Lantana camara. All extracts reduced mycelial growth and conidial germination of A. solani. In vitro studies showed that extracts obtained from A. sativum and A. indica have significant inhibition of mycelial growth of A. solani (88.80 and 86.62 percent) at 20 percent concentration. Higher concentrations of A. sativum extract caused a higher reduction of A. solani radial growth on potato dextrose agar medium. Extracts obtained from A. sativum and A. indica at 20 percent concentration, were found most effective for inhibition of conidial germination (85.50 and 80.04 percent) respectively of A. solani. Observations by scanning electron microscope (SEM) showed dramatic alteration in A. solani hyphae collapsed and spores shrinked when treated with extract of A. sativum at a 20 per cent concentration. The qualitative and quantitative analysis of various phytochemicals like flavonoids, alkaloids, saponins, tannins, steroids, terpenoids, glycosides, and phenols was showed A. sativum extract better than all the other plant extracts. Observation also revealed that 20 percent concentration of garlic extract has potential to inhibit to A. solani.

Author(s):  
Meseret Tadelo ◽  
Tamirat Wato ◽  
Tilahun Negash

Background: Tomato (Lycopersicon esculentum Mill.) belongs to the family Solanaceae. In Ethiopia, control of early blight is largely dependent on fungicidal application. There is a research need to identify effective botanical extracts to control Alternaria solani that cause early blight of tomato and for evaluation of plant extracts through different solvents on the target pathogen. Methods: In vitro experiment was conducted to evaluate the effectiveness of crude extracts of 16 selected medicinal plants against Alternaria solani. Thus, crude extracts were extracted from medicinal plants with different solvents (methanol, ethanol and petroleum at (25%, 50% and 100%) concentrations. The Alternaria solani was isolated from infected tomato leaves showing early blight symptoms. Evaluation of plant extracts was carried out against Alternaria solani using food poisoned technique on PDA. Result: Results showed that most of the methanolic extract plants were showed significant inhibition of the mycelial growth as compared to ethanolic and petroleum ether extracts. A higher rate of mycelial reduction was recorded by ethanol extracts of Allium sativum at all concentrations (100%) followed by methanol extracts of Allium sativum at 25%, 50%, 100% concentration (90.02%, 97.01%, 100% respectively). The effectiveness of extracts against Alternaria solani depends on use at the higher concentrations and various solvents. For crude extracts that have shown higher inhibitory effects against Alternaria solani in vitro conditions, actual chemical compounds should be identified. Furthermore, it is also important to evaluate these plants on other microbes, study to test in vivo and to assess their real potential field condition wherever early blight is an important disease of tomato.


2012 ◽  
Vol 48 (No. 2) ◽  
pp. 74-79 ◽  
Author(s):  
S.M.A. Nashwa ◽  
K.A.M. Abo-Elyousr

The antimicrobial activity of six plant extracts from Ocimum basilicum (Sweat Basil), Azadirachta indica (Neem), Eucalyptus chamadulonsis (Eucalyptus), Datura stramonium (Jimsonweed), Nerium oleander (Oleander), and Allium sativum (Garlic) was tested for controlling Alternaria solani in vitro and in vivo. In in vitro study the leaf extracts of D. stramonium, A. indica, and A. sativum at 5% concentration caused the highest reduction of mycelial growth of A. solani (44.4, 43.3 and 42.2%, respectively), while O. basilicum at 1% and 5% concentration and N. oleander at 5% concentration caused the lowest inhibition of mycelial growth of the pathogen. In greenhouse experiments the highest reduction of disease severity was achieved by the extracts of A. sativum at 5% concentration and D. stramonium at 1% and 5% concentration. The greatest reduction of disease severity was achieved by A. sativum at 5% concentration and the smallest reduction was obtained when tomato plants were treated with O. basilicum at 1% and 5% concentration (46.1 and 45.2 %, respectively). D. stramonium and A. sativum at 5% concentration increased the fruit yield by 76.2% and 66.7% compared to the infected control. All treatments with plant extracts significantly reduced the early blight disease as well as increased the yield of tomato compared to the infected control under field conditions.


2021 ◽  
Author(s):  
Vignesh Murthy ◽  
VedhaHari BodethalaNarayanan ◽  
MubarakAli Davoodbasha ◽  
MadhanShankar ShankarRamakrishanan

Abstract A novel strain of Bacillus isolated from rhizosphere has shown to be excellent biocontrol agents against various plant pathogens. In this study, a first report of a Bacillus strain NKMV-3 which effectively controlling Alternaria solani, which cause the Early Blight disease in tomato. Based on the cultural and molecular sequencing of 16S rRNA gene sequence, the identity of the strain was confirmed as Bacillus velezensis NKMV-3. The presence of the lipopeptide which are antibiotic synthesis genes namely Iturin C, Surfactin A, Fengycin B and D were confirmed through gene amplification. In addition, lipopetides was also confirmed through liquid chromatography. The extract showed inhibitory effect against A.solani in-vitro and detached tomato leaf assays. Bacillus velezensis strain NKMV-3 based formulations may provide an effective solution in controlling early blight disease in tomato and other crops.


2020 ◽  
pp. 1861-1874
Author(s):  
Camila Hendges ◽  
José Renato Stangarlin ◽  
Márcia de Holanda Nozaki ◽  
Eloisa Lorenzetti ◽  
Odair José Kuhn

The early blight (caused by the fungus Alternaria solani) results in significant damage to the tomato crop, directly affecting productivity. An alternative to the frequent use of pesticides is the use of essential oils, which can act in defense against phytopathogens. The objective of this work was to evaluate the toxic activity in vitro of the bergamot orange (Citrus aurantium ssp. bergamia) essential oil against A. solani, the control of the early blight, and the activity of defense enzymes in tomatoes treated with this oil and inoculated with A. solani. Mycelial discs of A. solani were added to dishes with V8 culture media to which essential oil at concentrations of 0, 500, 1000, 1500, 2000, and 2500 µL L-1, in addition to a standard fungicide treatment (azoxystrobin + difenoconazole, 200 + 125 g L-1, respectively) was added. The Petri dishes were incubated at 25 °C in the dark. Mycelial growth was evaluated daily for 19 days, when all treatments reached maximum growth. Sporulation analysis was performed thereafter. Tomato plants were treated with bergamot essential oil, 30 days after transplanting, in the concentrations and fungicide mentioned, in the second pair of leaves. After 72 hours, the pathogen was inoculated using a spray bottle, on treated leaves (second pair of leaves) and untreated leaves (third pair of leaves). The area under the disease progress curve (AUDPC) was calculated based on five severity assessments. The activity of peroxidase (POX), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) was evaluated in leaves treated with the concentration of 2500 µL L-1 of essential oil. The concentration of 2500 ?L L-1 reduced mycelial growth and sporulation of the pathogen by 68.15% and 29.48%, respectively. In treatments with application of essential oil, lower AUDPC was observed for a concentration of 2500 ?L L-1, which was statistically similar to that observed for fungicide application, both in treated and untreated leaves. A greater activity of PPO, POX, and PAL was found locally and systemically, both in the second and third leaves, at concentration of 2500 ?L L-1. The essential oil of bergamot can be an alternative for the control of early blight in tomato.


2021 ◽  
Vol 58 (04) ◽  
pp. 1263-1275
Author(s):  
Rashid Iqbal Khan

Plant extracts (PE’s) has emerged as a safer alternative to manage the fungal pathogens affecting tomato productivity. The current study aimed to evaluate the antimicrobial potential of methanolic fenugreek extract against Alternaria solani, a causal agent of early blight disease in tomato. Fenugreek extract was used at different concentrations of 5%, 10%, 15%, 20% and 25% under in vitro conditions. Results concluded that 25% fenugreek extract significantly reduced the radial growth (2.5 cm) of A. solani under in vitro conditions. Based on in vitro results, three concentrations (5%, 15% and 25%) of fenugreek extract was examined under greenhouse and field conditions. The outcomes expressed that 5% fenugreek extract reduced the disease severity up to 30.19% under greenhouse conditions and up to 40.53% under field trials. Although, application of fenugreek extract had exhibited non-significant impact on vegetative and reproductive growth parameters. However, its application had proved better results as compared to those plants which are infected with A. solani but received zero application of fenugreek extract. Furthermore, the effectiveness of plant extracts was evaluated by variant photosynthetic, antioxidative, polyphenolic and hypersensitive response of A. solani affected tomato plants. The 25% fenugreek extract application had augmented the chlorophyll pigments along with the significant increment of superoxide dismutase (174.16 U mg-1 protein), peroxidase (7.61 µmol min-1 g-1 protein) and catalase activity (4.73 nmol min-1 g-1 protein). Similar outcomes were observed regarding phenolic compounds, where 5% fenugreek extract application had enhanced flavonoid levels (26.62 mg QuE g-1), tannins (1.28 mg TE g-1 extract) and total phenolic contents (2.39 mg GAE g-1) in tomato leaves demonstrating its protective effect against early blight. In dose response, 25% fenugreek extract was most effective in reducing lipid peroxidation and enhancing H2O2 levels. The outcomes of study exhibited the fenugreek extract as an effective strategy to be used against A. solani to control early blight infection in tomato plants. Thus, it can serve as suitable fungicide alternative for resource-poor agriculture areas mainly in developing countries.


2021 ◽  
Vol 21 (no 1) ◽  
Author(s):  
B. Rex ◽  
G. Rajasekar

Early blight of tomato (Solanum lycopersicum L.) incited by Alternaria solani is highly destructive causing yield loss up to 78 per cent. The fungus was tested with different media along with the host extract and different nutrient sources for their growth and development in in vitro. Twelve different media were tested on the growth of A. solani, among them potato dextrose agar + host leaf extract recorded maximum radial mycelial growth of A. solani (89.57mm) and potato dextrose broth + leaf extract has maximum mycelial dry weight (613mg). Six carbon and nitrogen sources amended media were tested. Among carbon sources, glucose recorded maximum radial mycelial growth (74.65mm) and mycelia dry weight (709.17mg). Among the nitrogen sources, ammonium nitrate has the enhanced the radial mycelail growth (84.56 mm) and high mycelial dry weigh (654.27mg). This study will be helpful for further investigations on the physiology of the fungus and management of the disease.


2021 ◽  
Vol 16 (2) ◽  
pp. 153-158
Author(s):  
Antônio Jussiê da Silva Solino ◽  
Juliana Santos Batista Oliveira ◽  
Sergio Augusto Cesnik ◽  
Kátia Regina Freitas Schwan-Estrada

Rare earth elements have been tested in control of plant diseases. Lanthanum (La) was tested in the control of Alternaria solani (in vitro) and tomato early blight (in vivo) using the concentration 0; 0.1; 0.2; 0.4 and 0.8 g L-1. In vitro, the concentration were diluted in V8 culture medium and evaluated for mycelial growth rate index (MGRI) and pathogen sporulation. In vivo, 24 hours after the application of concentration was inoculate the pathogen and 24 hours after the inoculation, leaflets were collected for quantification, the specific catalytic activity and guaiacol peroxidase. The severity of tomato early blight were also analyzed. As 0.27 and 0.28 g L-1 reduces 28% and 50% the MGRI and the sporulation, respectively. Peroxidase and catalase activity was increased by 298% and 151% in tomato treated with 0.5 and 0.4 g L-1de La, respectively. In vivo reduces AUDPC 70% when was applied 0.27 g L-1 La. Lanthanum can be used as resistance inducer in controlling tomato early blight.


Author(s):  
MH Hossain ◽  
I Hossain

Efforts have been made to assess some plant extracts namely, Lycopersicon esculentum, Tagetus patula, Achras sapota, Azadirachta indica, Datura metel, Cymbopogon citrates, Polyalthia longifolia, Allium sativum and Allium cepa in vitro for the management of leaf spot (tikka) disease of groundnut cultivar Dhaka-1 caused by Cercospora arachidicola and Cercosporidium personatum. Results indicated that all the tested plant extracts and BAUBiofungicide suppressed the growth of mycelium and inhibition of conidial germination of C. arachidicola and C. personatum. Among the treatments, the leaf extracts of L. esculentum showed the most effective followed by leaf extract of D. metel, A. indica and BAU-Biofungicide in case of mycelial growth and conidial germination. Other plant extracts also had inhibitory effects. In case of conidial germination and germination inhibition, the least effective plant extract was C. citrates. Leaf extract of A. sapota was the least effective in case of mycelial growth. DOI: http://dx.doi.org/10.3329/ijarit.v3i2.17842 Int. J. Agril. Res. Innov. & Tech. 3 (2): 36-40, December, 2013


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