Nutritional and morpho-physiological studies of Sclerotinia sclerotiorum causing stem rot of Indian Mustard (Brassica juncea)

Infection occurs on leaves, stems and pods at different developmental stages particularly at flowering stage, causing seed yield losses up to 80%, as well as significant reductions in oil content and quality.In order to standardize the media for optimum growth of the pathogen, compared on different solid and liquid media. The number of sclerotia as well as colony growth was maximum on potato dextrose agar. Among different liquid media Czapek'sdox followed by Richard's and potato dextrose broth supported good mycelial growth and sclerotial formation. The optimum temperature and relative humidity for fungal colony growth, was found 20°C with 90% relative humidity. Both mycelial growth and sclerotial production decreased with increase in temperature above 30°C. The optimum pH for the growth of the fungus was found to be 4.5.