Effect of Different Doses of Fungicide (Mancozeb) against Alternaria Leaf Blight of Tomato in Tunnel

Tomato (Lycopersicon esculentum Mill.) is an important commercial vegetable of the world.Tomato cultivars cultivated in Pakistan have low level of genetic resistance to Alternaria leaf blight disease.Farmers, in pursuance of high yield are inclined to cultivate some varieties which may be less resistant to the disease and rely on fungicide applications for the control of Alternaria solani, the casual organism of Alternaria blight of tomato.Five tomato varieties (Litah545, Litah514, Eurica, Ti-166 and Astra) were sown in five replications with one standard check in tunnel.Different doses of mancozeb (4 g/L, 8 g/L, 12 g/L and 16 g/L of water) were applied after 7 days intervals.Disease data was recorded after ten days interval from flowering stage to onward.Average yield of each variety was calculated after ten pickings.All fungicide doses reduce the disease severity as compared to untreated check.The highest reduction in the disease was achieved by applying mancozeb 12 g/L of water at an interval of 7, 14, 21 and 28 days.The yield of Litah545 and Litah514 give higher yield as compared to Eurica, Ti-166 and Astra.Overall results revealed that weekly sprays of mancozeb at 12 g/L of water were cost effective and eco-friendly for the management of Alternaria blight of tomato.