Evaluation of Culture Media for Growth Characteristics of Alternaria solani, Causing Early Blight of Tomato

Early blight is most common and devastating disease in tomato plant caused by deuteromycotina fungi, Alternaria solani. This fungus grows well in potato dextrose agar and Richard’s broth medium in vitro. The growth of the fungi were tested under culture in twelve different liquid and solid media and compared with each other. Potato dextrose agar and oat meal agar among solid media and Richard’s broth and Sabouraud’s broth among liquid media appeared to be better than other media for growth of tomato early blight causing fungi. The growth characteristics such as color of colony and substrate, margin of colony, topography of mycelium along with the sporulation of the test fungus were studied on these solid media. Fungus sporulation was best in oat meal agar media. Maximum growth of the fungus was observed at 8 days after inoculation with continuous increasing growth in the potato dextrose broth (PDB) medium, although growth rate was decreasing after the 2 days of inoculation. This study will be helpful for further investigations on the physiology of the fungus and management of the disease. This investigation may be useful for taxonomic study of the fungus.