The Pathogenicity Test, Cultural and Morphological Characterization of Anthracnose (Colletotrichum lindemuthianum) of Green Gram (Vigna radiata L. Wilczek)

Abstract

Aims: The objective of this study was to identify the appropriate anthracnose fungus of green gram using symptomatology, identification, pathogenicity test and characterization of samples. Study Design:  Pathogenicity test, cultural and morphological characterization. Place and Duration of Study: The laboratory studies were conducted in the Department of Plant Pathology, N. M. College of Agriculture, Navsari Agricultural University, Navsari, Gujarat during rabi 2020-21. Methodology: The sample was collected and subjected to isolation, purification and identification of pathogen. Four different pathogenecity tests were conducted to verify the pathogen causing anthracnose of green gram. On the other hand, the cultural and morphological characteristics of pathogen were studied.  Results: The pathogenecity test confirmed that the pathogen as Colletotrichum lindemuthianum in all four tests. Spraying inoculum after needle pricking and carborandum powder producing 100% infection in inoculated plants while 96% in spraying spore suspension without any abrasion. The less per cent of infection was observed in seed inoculated plants. The cultural studies of C. lindemuthianium shown sub-aerial whitish-to-pink cottony growth and pinkish-to-brown pigmentation under the culture plate. The morphological study of C. lindemuthianium observed as single-celled, hyaline, cylindrical, and smooth with oil globules. The acervuli were blackish brown and measure 181.3 × 254.6 µm. The setae were visible through the conidial mass with 1-3 septations. Conclusion: A study on green gram anthracnose confirmed C. lindemuthianum as pathogen in all four pathogenicity test with needle pricking and carborandum powder producing 100% infection in inoculated plants while 96% in spraying spore suspension without any abrasion. Cultural studies revealed whitish-pink cottony growth and pinkish-brown pigmentation. C. lindemuthianium was morphologically observed as single-celled, hyaline, cylindrical, smooth, with oil globules, blackish brown acervuli, and visible setae through conidial mass with 1-3 septations. Therefore, these findings are important for identifying the anthracnose disease of green gram.