Chapter 7 - Biotic stresses and their management

Abstract

Recognizing the importance of ‘Millets’ comprising of sorghum (Jowar), pearl millet (Bajra), finger millet (Ragi/Mandua), foxtail millet (Kangani/kakun), proso millet (Cheena), kodo millet (Kodo), barnyard millet (Sawa/Sanwa/Jhangora), little millet (Kutki) and brown top millet (Korle), the Ministry of Agriculture and Farmers Welfare, Government of India has declared them as ‘Nutri-Cereals’ for production, consumption and trade point of view. The move is aimed at removing a lingering perception that these grains are inferior to rice and wheat, even as their health benefits are larger. Millets and pseudo cereals like buck-wheat (Kuttu), amaranth (Chaulai), chia and quinoa are gluten free and non-allergenic. Millet consumption decreases triglycerides and C-reactive protein, thereby preventing cardiovascular disease. All millets are rich in dietary fibre, which has water absorbing and bulking property. It increases transit time of food in the gut which helps in reducing risk of inflammatory bowel disease and acts as detoxifying agent in the body. Biotic stresses incited by fungi, bacteria, virus, nematodes, insects, birds, weeds and parasitic plants are the most important constraints responsible for considerable yield losses in agricultural production worldwide. The intensity of biotic stress varies depending on the weather, cropping system, cultivation practices, type of crops, crop varieties vis-à-vis their resistance level. Generally, hot and humid weather, intensive cultivation and poor crop management practices make the crop vulnerable to these stresses. Millets and pseudo cereals are climate resilient crops and adverse effect of biotic stresses in these crops is less compared to other crops. In the recent past, due to climate change outbreak of certain diseases is reported in millet crops more so in the high yielding varieties under intensive cultivation. In general, millets and pseudo cereals suffer more from fungal diseases than bacterial, viral and nematode diseases. The important diseases of millets are grain mould (sorghum), downy mildew (sorghum, pearl millet, finger millet, foxtail millet), blast (finger millet, foxtail millet, pearl millet), leaf blight (kodo millet, little millet, barnyard millet, finger millet), smut (sorghum, pearl millet, kodo millet, little millet, foxtail millet), rust (foxtail millet), and ergot (sorghum, pearl millet). In millets, apart from the major diseases several endemic diseases viz. Cercospora leaf spot, brown spot, banded blight, foot rot etc., are causing yield losses. Details of biotic stresses of millets and pseudocereals and their management are discussed in this section.