Management of Early Blight of Tomato Caused by Alternaria solani by Using Bio-inoculants and Chitosans under Greenhouse Conditions

Tomato (Lycopersicon esculentum.L) is one of the most important economic vegetable crop cultivated in India. Among various diseases caused by fungal, bacterial and virus pathogens, early blight caused by Alternaria solani is a major concern for the farmers as it not only affects vegetative parts but also fruits. The study was aimed at developing eco-friendly alternatives for chemicals currently used for the management of A. solani by using biocontrol agents and chitosans with a spin-off benefit of plant growth promotion and activate innate defense mechanisms. The potential biocontrol agents identified in the previous experiments viz. Trichoderma (T4), Pseudomonas (P28) isolates and effective chitosans DA10, 134 were used either singly or in combinations for their efficacy against A. solani in vivo against Propiconazole @ 0.1% and water spray, as positive and negative controls treatments, respectively. Propiconazole @ 0.1% was highly effective in reducing the disease over other treatments. However, the treatments viz. seed coating with Trichoderma (T4) coupled with DA 10 chitosan (simultaneously applied) or DA 10 chitosan alone were also significantly effective and on par with the fungicide treatment indicating that alternatives to fungicides could be explored after field evaluation and large-scale demonstration of these treatments and their economic viability.