Cultural and Morphological Characterization of the Pathogen (Rhizoctonia solani L.) Causing Web Blight of Mungbean

Abstract

A study was carried out to characterize isolates of pathogen causing web blight in mungbean by adopting the morphological and cultural features. The isolates were recovered from diseased plant samples representing different locations of Punjab. In microscopic study, all the isolates exhibited typical characters of Rhizoctonia e.g. right-angle branching near the distal septum and constriction at the base of branching. Cultural and morphological study revealed that Rhizoctonia isolates differed in terms of mycelial colour, texture, growth rate, number and colour of sclerotia. The mycelial colour of five isolates varied from cream brown to dark brown. Ballowal Saunkhri (BS) and Nawanshahr (NS) isolates showed fast growth (0.88 mm/h) while Ludhiana isolates (L1, L2) were slow growing (0.81, 0.68 mm/h). Mycelial texture was flat in all isolates except Ropar (RO) isolate which was semi cottony. Mycelial width ranged from 4.74 µm (L1) to 6.43 pm (NS). Along with isolate BS, L2 produced the highest number of sclerotia (>60/plate) in spite of its slowest growth rate. Vegetative compatibility was observed in isolates combination of L1-L2, BS-L1, RO-L1, NS-L1 and NS-BS. The outcomes of present study related to growth rate and ability of sclerotia production may be used in future research to correlate with the pathogen's virulence.