Cultural and morphological characterization of Colletotrichum capsici causing anthracnose of chilli (Capsicum anum L.)

Abstract

Anthracnose of chilli, incited by Colletotrichum capsici, is a major concern for the farmers in various parts of the country. An experiment was undertaken to study the cultural and morphological characterization of the pathogen through in vitro studies. Results revealed that OMA was found to be best for maximum radial growth (90.00 mm) of the test pathogen followed by CFDA (88.67 mm) whereas minimum radial growth (69.34 mm) was observed inRSA. Among five different temperature, maximumradial growth (89.87mm) of the pathogen was recorded at 30 oC followed by 25 oC (84.83mm) whereas at 40 oC, no radial growth was found. Among the five different pH tested, pH 7.0 was found to be best suited for the radial growth of the pathogen (83.67 mm) followed by pH 8.0 (81.00 mm) whereas minimum radial growth was recorded at pH 4.0 (74.33mm). Colony culture of the fungus showed grayish to white colony colour with fluffy texture and smooth margin in OMA, PDA, CDA, RSA and MEA whereas brown to black with thin scanty mycelium was observed in CFDA. Microscopic observation (40X) revealed that mycelium was dense, filamentous and septate, acervuli with brown coloured and rounded. Setae were brown to black in colour long needle like, swollen at base and tapering towards apex having size of 110-272μm ×4-6 μm with 2-5 septa per setae. Conidia were hyaline, single celled, sickle shaped, presence of oil globules with size 18-27 µm × 2.1-4.1 µm.