Studies on symptoms and morphological characteristics of Sorosporium paspali-thunbergii (Henn.) Ito causing head smut in Kodo Millet

Head smut caused by Sorosporium paspali-thunbergii is an important externally seed borne disease of kodo millet and causes economic yield loss. Characteristic symptoms of the disease consists of conversion of all the infected ear heads into long smut sori ranging from 5.5 to 12.4 cm. Smut sorus was surrounded with a delicate creamy membrane at early stage that bursts during maturity and exposed the teliospores. Individual teliospores were globose to sub-globose, angular, yellowish brown to dark brown and remained in loose spore balls of varying shape and size. Maximum spore germination was recorded in 2% glucose solution (58.0%) followed by 1% glucose solution (53.4%) and tap water (50.3%). Higher spore germination was recorded in teliospores stored with host as compared to naked teliospores stored in paper bags. Decreasing trend in mean teliospore germination from 55.2 to 37.4% was observed in storage period of 30 to 105 days. Maximum viability was recorded in teliospores stored in paper bags at 4°C.