National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Tomato is one of the most important vegetable crops cultivated for its fleshy fruits. Rhizoctonia solani is the most important soilborne pathogen of tomato crop and in recent past it is known to cause blight symptoms on stems of tomato plants which has become a serious threat to tomato cultivation in Ranga Reddy district of Andhra Pradesh. The pathogen was isolated on PDA from blight affected tomato plants collected from farmers’ fields and was identified as Rhizoctonia solani based on its cultural and morphological characteristics. The culture of the fungus was greyish white in the beginning which later turned to black in color with cottony aerial mycelial growth. The hyphae produced branches mostly at right angles with constriction at the origin of branch and often formed a septum near the branch origin. The fungus produced microsclerotia of 0.8 - 1.0 mm in size in sixty days old cultures. Of the three inoculation methods, root dip inoculation was found to be the best as it resulted in maximum per cent disease incidence (96.67) in a short period of incubation (two days). Symptoms produced due to soil infestation and root dip inoculation appeared as typical damping off symptoms with dark brown lesions at the collar region and yellowing of leaves which lead to death of seedlings. Whereas, in case of stem application the initial symptoms appeared as water soaked lesions on stems which later became oval to irregular light brown necrotic spots. Mature spots on stems appeared as large brown blighted portion with typical cracks on the bark. In advanced stages plant collapsed at infected portion leading to death of the plant.
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