Approaches for Diagnosis and Management of Banded Blight in Small Millets

Abstract

Small millets comprising finger millet, little millet, Kodo millet, foxtail millet, barnyard millet, proso millet and brown top millet is important region-specific cereal crops of the semi-arid, tribal, and hill areas of the world. These are versatile, low water demanding, climate-resilient crops and adaptable for different cropping patterns. In India, small millets are cultivated in 1.64 m ha with a a production of 1.83 m tons and an average yield of 1038.5 kg ha–1 (2016–2017). These crops provide household food and nutritional security in resource-poor farmers. Small millets, now known as nutricereals are rich sources of dietary fiber, phytochemicals, micronutrients, and known to reduce diabetic Mellitus, celiac, and cardiovascular diseases. Banded blight caused by Rhizoctonia solani Kuhn [Basidial stage; Thanatephorus cucumeris (Fr.) Donk] is becoming a serious threat for a sustainable yield of small millets since last few years. The causal pathogen is a polyphagous, necrotrophic fungus, primarily soil-borne in nature, wide host range, and genetically diverse showing variability in cultural, morphological, and physiological characters. Small millets are attacked by the pathogen at all the stages of crop growth and symptoms appeared as characteristic banded blight pattern in the sheath and leaves. Significant yield loss was reported in small 164millets due to banded blight. A temperature of around 28–30C and relative humidity of 70% or above favors the rapid disease development. Most of the isolates of R. solani collected from small millets are reported cross infective with each other. The dearth of information is available on various aspects of banded blight, though few studies have been made to identify resistant sources, morphological characteristics of the pathogen, disease progression, host range, and management of the disease through botanicals, biocontrol agents, and chemicals in different small millets. In this chapter, a critical review on symptomatology, etiology, host plant resistance, and management of banded blight in small millets has been carried out.