Morpho-Cultural Characterization of Post-Harvest Fungal Pathogens of Onion
Ratnaprabha.
Department of Plant Pathology, College of Agriculture, Raichur, India.
Amaresh, Y. S. *
Department of Plant Pathology, College of Agriculture, Raichur, India.
Yenjerappa, S.T.
Department of Plant Pathology, College of Agriculture, Raichur, India.
Gowdar, S. B
Department of Plant Pathology, College of Agriculture, Raichur, India.
Arunkumar, H
Seed Unit, University of Agricultural Sciences, Raichur- 584104, Karnataka, India.
*Author to whom correspondence should be addressed.
Abstract
Three post harvest fungal pathogens, Penicillium spp., Fusarium spp., and Colletotrichum spp., were isolated from infected onion bulb samples collected during a survey in seven districts of Kalyana Karnataka. Pathogenicity tests were conducted following Koch’s postulates, Morphological characterization revealed septate, hyaline hyphae in all pathogens, with Fusarium spp. Producing falcate macro conidia. Colletotrichum spp. cylindrical conidia containing oil globules and Penicillium s pp.produced globe-shaped conidia in chains. Cultural studies showed maximum colony diameter for all pathogens on Potato dextrose agar with Fusarium spp. (89.76 mm), Colletotrichum spp. (89.40 mm) and Penicillium spp. (90.00mm). Potato dextrose agar and Richard’s agar supported abundant sporulation for Fusariumspp. and Colletotrichumspp.while Penicillium spp. sporulated best on Potato dextrose agar. Colony colour, growth pattern and sporulation varied across media, with potato dextrose agar generally supporting highest growth and pigment development. The results confirm the pathogenic potential and cultural preferences of these fungal species.
Keywords: Onion, cultural characters, morphological characters, pathogenicity test, roving survey