Growth dynamics of Rhizoctonia solani isolates causing web blight in black gram (Vigna mungo L.)

Rhizoctonia solani, the causative agent of web blight in black gram (Vigna mungo), poses a significant threat to pulse productivity during wet seasons. This study aimed to characterize the pathogen’s growth dynamics under laboratory conditions. Symptomatology revealed typical necrotic lesions and sclerotia formation on infected tissues. The pathogen was morphologically identified by right-angle branching. Colony growth comparisons of three R. solani isolates on potato dextrose agar (PDA) showed statistically significant differences across 5-time intervals. Isolate Rs3 exhibited the highest mean radial growth (5.832 cm), indicating substantial genetic variability. Further evaluation across five culture media revealed Czapek Dox Agar as the most conducive medium (mean growth 6.127 cm), followed closely by Sabouraud's Dextrose Agar. The findings underscore the variability in pathogen behavior.