Hot Water Treatment – A physical strategy deployed in checking the Septoria leaf spot of tomato incited by Septoria lycopersici Speg.

Septoria leaf spot ( Septoria lycopersici Speg.) is the one of most serious foliar diseases of tomato. It mainly occurs on young leaves leading to severe defoliation which later proliferates in fruits and contributes towards detrimental yield losses. Considering the seed borne nature of pathogen, goal of present research was to eradicate the inoculum of disease from seeds by giving hot water treatment in vitro and evaluating its effect in vivo . Tomato seeds were subjected to hot water treatment (HWT) at temperature regimes 48, 50, 52 and 55°C at two different time intervals 15 and 30 minutes, amongst which HWT with 48°C at 30 minutes duration was found most effective in respect of increasing germination percentage (89.83%), seedling length (18.00cm), seedling vigour (1617.76), seedling dry weight (18.03mg) and minimum 4.19% seed infection. Under field condition also the same seeds treatment was found effective by giving reduction in the disease severity and incidence levels up to 47.01 and 33.26%, respectively. Next best temperature regime recorded was 50°C for 30 minutes which minimized the Septoria lycopersici seed infection with beneficial effect on seed growth parameters. Thus, present study come up with the new strategy to manage Septoria leaf spot by giving physical method of hot water as pre-treatment to tomato seeds that helped in reduction of disease spread and severity under field conditions, moreover improves the plant growth parameters and had a potential to substitute chemical fungicides.