Investigations on Variability and Eco-friendly Management of Alternaria alternata Causing Tomato Blight

Investigations on Variability and Eco-friendly Management of Alternaria alternata Causing Tomato Blight.

Different isolates of Alternaria alternata showed variations in symptoms, growth characteristics, colony diameter, pattern of sporulation, size of conidia and mean number of septa. Of four isolates, Aa-1 produced maximum colony diameter (62.00 mm), sporulation, percent infection (80.00), conidia length (69.75μm), beak length (24.45μm) and horizontal septation (8.45). The shape and colour of the culture of different isolates varied from compact colony growth, dark brown colour in the center having white periphery, concentric rings prominent in AA-1 isolates. Out of six fungicides, Mancozeb was found to be the most effective against mycelial growth of A. alternata. In respect to plant extract and bio-control Azadirachta indica and Trichoderma viride caused maximum inhibition of A. alternata growth as compared to other bio-agents. In pot and field experiments, maximum efficacy of per cent disease control (66.56) and yield (22.99 t/ ha) was recorded in seed treatment and two foliar spray of Mancozeb...