Management of gray leaf spot of tomato caused by Stemphylium lycopersici under protected cultivation

Gray leaf spot of tomato caused by Stemphylium lycopersici (Enjoji) W. Yamam under protected cultivation causes huge losses in the tomato growing areas of the world. Effective management of the disease through both chemical and non- chemical methods is necessary to minimize the economic losses. The present study was conducted for evaluation of cultural, biological and chemical methods of disease management. The disease was found to be very severe in March-transplanted and in closely spaced crop (45x30 cm). In vitro testing of bioagents viz., DMA8 (T. konigii), JMA-4 (T. harzianum), SMA-5 (T. harzianum) and JMA-11 (T. koningii) showed inhibition of S. lycopersici growth, ranging from 83.3–88.2 per cent. Among the 11 fungicides tested against the pathogen in vitro, tebuconazole 25.9% EC and propiconazole 25% EC showed 100 per cent inhibition of mycelial growth at 250 ppm, followed by propineb 70WP at 750 ppm. Carbendazim 50 WP was observed to be the least effective. Under polyhouse condition, three sprays of tebuconazole 25.9% EC @ 0.5 ml/lt and propiconazole 25% EC @ 1ml/lt at an interval of 10 days were found most effective showing 89.3 to 88.9 per cent disease control and >200 per cent increase in the yield.