Role of nutrients and lower leaf removal against Alternaria blight in Indian mustard (Brassica juncea L.)

Abstract

Alternaria Blight (AB) caused by Alternaria brassicae and A. brassicicola is a major constraint in rapeseed-mustard production in India. An experiment was conducted during 2009-10 and 2010-11 to study the effect of nutrients and lower leaf removal in Indian mustard (Brassica juncea L.) on AB disease. Results indicated that maximum AB reduction (26%) was observed by soil application of Potash at 40 kg haG1+Zinc sulphate at 25 kg haG1+Copper sulphate at 40 kg haG1+Sulphur at 10 kg haG1+Ridomil-MZ 72 as foliar spray at 0.25% was better when applied as foliar spray (21%). However, three lower leaves removal at 40 Days After Sowing (DAS) with Foliar Spray (FS) of Ridomil MZ- 72 at 0.25 also reduced the disease (19%) as similar with leaf removal (18.9%) alone in combination with no treatment. Soil application of K+ZnSO4+CuSO4+S+leaf removal+FS of mancozeb+carbendazim and lower leaf removal at 40 DAS+FS of ridomil altogether reduced the maximum disease severity (37.9%). A linear equation was found between Zn, Cu, S and K with R2 = 0.55, 0.38, 0.15 and 0.59, respectively, during 2009-10 and R2 = 0.52, 0.30, 0.27 and 0.51, respectively during 2010-11 showed decrease in AB severity with increase of nutrient content in leaves. Data revealed that leaf removal at 40 DAS vis-a-vis use of nutrients along with fungicidal foliar spray reduced the AB of Indian mustard. Because the use of nutrients take part in induced tolerance and lower leaf removal keep away from the reach of inoculum to the plants, both plays a key role to minimize disease severity in Indian mustard resulted higher seed yield and there adoption could be economic and eco-friendly to the farmers.