Study on in-vitro efficacy of botanicals and chemicals against Alternaria solani associated with post-harvest rot of tomato (Lycopersicon esculentum Mill.)

Tomato (Lycopersicon esculentum Mill.) is one of the major vegetable fruit crop in the state of Maharashtra and widely grown in Marathwada region throughout year. It is known to be affected by several fungal diseases. Based on symptomatology, microscopic observations and pathogenicity test, the test pathogens were identified as Alternaria solani and its further identity was confirmed. The pathogen (Alternaria solani) was isolated successfully from the naturally infected fruits of tomato. Culture was purified and maintained for further studies. In in vitro study, all tested botanicals/plant extracts were found effective in inhibition of mycelial growth of A. solani. Least mycelial growth (00.67 mm) was recorded with maximum mycelial growth inhibition with Garlic extract (99.25%) which was at par with treatment of Nilgiri oil (97.77%) and followed by Ginger rhizome extract (79.63%), Tulsi (70.74%), and Onion bulb extract (70.00%). While least mycelial inhibition was recorded with Turmeric rhizome extract (64.82%) and Neem leaf extract (57.04%). All the tested chemicals were found fungistatic against A. solani. Calcium chloride and Boric acid at both concentration 1 & 2% were found most effective in inhibiting the mycelial growth of Alternaria solani, while least inhibition of these fungi was observed with Potassium chloride and Sodium bicarbonate.