scholarly journals Cultural, Morphological and Biochemical Variability Studies among the Isolates of Alternaria solani, the Causal Agent of Early Blight Disease of Tomato

2021 ◽  
Vol 12 (5) ◽  
pp. 584-593
Author(s):  
Nagesh - ◽  
◽  
S. K. Mushrif ◽  
C. G. Sangeetha ◽  
T. B. Manjunatha Reddy ◽  
...  
Keyword(s):  
Mycelial Growth ◽  
Early Blight ◽  
Agar Medium ◽  
Alternaria Solani ◽  
Maximum Growth ◽  
Causal Agent ◽  
Morphological Studies ◽  
Karnataka State ◽  
Biochemical Variability ◽  
Blight Disease

Present experiment was conducted at College of Horticulture, Bengaluru (KA) during year 2017–18 to study the cultural, morphological and biochemical variations among the isolates of the pathogen Alternaria solani, the causal agent of early blight disease in tomato. The results revealed variation among the isolates collected from different regions of Karnataka state, India with regard to the colony characteristics viz., colony colour, mycelial growth pattern, margin of the colony and zonations whereas the maximum mycelial growth in terms of diameter (90 mm) was observed in the isolates Bagalkot (BaBG) and Chikkamagaluru (CMH) on Czapek’s (Dox) agar medium while the least growth (36.33) was noticed in Bidar (BiHH) isolate. The isolate could grow better on Czapek’s (Dox) agar medium as among the 3 media tested Czapek’s (Dox) agar medium produced maximum growth of 80.70 mm and the least growth (63.70 mm) was noticed in V-8 juice agar. The morphological studies revealed that all the conidia of various isolates varied in length (25.07–42.90 µm), breadth (10.53–21.52 µm) and number of horizontal septa (2–7), longitudinal septa (0–4). Biochemical studies among the isolates revealed significant variation in their enzyme activities. The peroxidase activity was more in Chikamagaluru (CMH) isolate (81.80 Unit g-1 FW) least activity was found in Bidar (BiHH) isolate 11.78 Unit g-1 FW whereas the esterase activity was more Bengaluru (BYC) isolate (69.01 Unit g-1 FW) least activity was found in Bagalkot (BaBG) isolate 11.78 Unit g-1 FW. Existence of variation among the isolates of Alternaria solani evident from the results obtained.

Antagonistic Potential of Macrolepiota sp. Against Alternaria Solani as Causal Agent of Early Blight Disease in Tomato Plants

2019 ◽  
Vol 72 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Jesús S. Hernández-Ochoa ◽  
Laura N. Levin ◽  
Carlos E. Hernández-Luna ◽  
Juan Francisco Contreras-Cordero ◽  
Guillermo Niño-Medina ◽  
...  
Keyword(s):  
Early Blight ◽  
Alternaria Solani ◽  
Causal Agent ◽  
Tomato Plants ◽  
Antagonistic Potential ◽  
Blight Disease

scholarly journals Antifungal activity against Alternaria solani and control of early blight in tomato by essential oil of bergamot orange

2020 ◽  
pp. 1861-1874
Author(s):  
Camila Hendges ◽  
José Renato Stangarlin ◽  
Márcia de Holanda Nozaki ◽  
Eloisa Lorenzetti ◽  
Odair José Kuhn
Keyword(s):  
Essential Oil ◽  
Mycelial Growth ◽  
Early Blight ◽  
Culture Media ◽  
Alternaria Solani ◽  
Maximum Growth ◽  
Tomato Crop ◽  
Toxic Activity ◽  
Progress Curve

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.

scholarly journals Evaluation of various plant extracts against the early blight disease of tomato plants under greenhouse and field conditions

2012 ◽  
Vol 48 (No. 2) ◽  
pp. 74-79 ◽  
Author(s):  
S.M.A. Nashwa ◽  
K.A.M. Abo-Elyousr
Keyword(s):  
Disease Severity ◽  
Plant Extracts ◽  
Mycelial Growth ◽  
Early Blight ◽  
Field Conditions ◽  
Nerium Oleander ◽  
Tomato Plants ◽  
Infected Control ◽  
Blight Disease

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.

Evaluation of tomato genotypes for early blight disease resistance caused by Alternaria solani in Pakistan

2019 ◽  
Vol 101 (4) ◽  
pp. 1159-1170
Author(s):  
Khalid Pervaiz Akhtar ◽  
Najeeb Ullah ◽  
Muhammad Yussouf Saleem ◽  
Qumer Iqbal ◽  
Muhammad Asghar ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Early Blight ◽  
Alternaria Solani ◽  
Blight Disease ◽  
Tomato Genotypes

scholarly journals Inheritance of Resistance to Early Blight Disease in Tetraploid × Diploid Crosses of Potatoes

HortScience ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 224-226 ◽  
Author(s):  
A.B. Herriott ◽  
F.L. Haynes ◽  
P.B. Shoemaker
Keyword(s):  
Partial Correlation ◽  
Early Blight ◽  
Alternaria Solani ◽  
Inheritance Of Resistance ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Breeding Lines ◽  
Blight Disease ◽  
Different Levels ◽  
Partial Correlation Coefficient

Heritability of resistance to early blight disease in potatoes (Solarium tuberosum L.) incited by Alternaria solani (En. & Martin) Ser. was estimated in tetraploid × diploid crosses. Susceptible tetraploid cultivars and breeding lines were the female parents. Diploids that produced a high proportion of first-division restitution (FDR) gametes and possessed different levels of early blight resistance were the male parents. Tubers from seedlings that resulted from the tetraploid × diploid crosses were planted in a field and artificially inoculated with spores of Alternaria solani. Resistance was measured as the slope (r) of the regression of the logit of the percent defoliation of each plant vs. time. Higher r values indicated lower resistance. Mean r values ranged from 0.123 to 0.157 for the tetraploid parents, and from 0.054 to 0.116 for the diploid parents. Mean r values for the tetraploid × diploid crosses were intermediate, ranging from 0.077 to 0.143. Narrow-sense heritability (h2) was 0.815. The partial correlation coefficient between r and mean maturity values was – 0.2086.

scholarly journals A Novel Rhizospheric Bacterium, Bacillus Velezensis NKMV-3 as a Biocontrol Agent against Alternaria Leaf Blight in Tomato

2021 ◽  
Author(s):  
Vignesh Murthy ◽  
VedhaHari BodethalaNarayanan ◽  
MubarakAli Davoodbasha ◽  
MadhanShankar ShankarRamakrishanan
Keyword(s):  
Early Blight ◽  
Plant Pathogens ◽  
Alternaria Solani ◽  
Inhibitory Effect ◽  
Rrna Gene ◽  
Bacillus Velezensis ◽  
Bacterium Bacillus ◽  
Blight Disease ◽  
Molecular Sequencing

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.

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