184 



THE SMUT OF NACHANI OR RAGI [ELEUSINE 

 GORACANA GAERTN.) 



By G. S. KULKARNI. 



(With 2 Text-figures.) •. 



This smut was first observed by the writer in 1918 at Malkapur in the 

 Kolhapur State. Later it was collected in the districts of Surat, Nashik, 

 and Ratnagiri in the Bombay Presidency. 



The disease is visible only in scattered grains in the head, the 

 majority of grains developing normally. Sometimes the affected grains 

 are single, sometimes grouped in patches of varying size, frequently 

 confined to one side or towards the base or apex of the head. 



The sori occur in the ovary as round or occasionally elongated bodies. 

 These project beyond the glumes and they may be from one to six times 

 the diameter of the normal grains (Fig. 1), being often 3-8 mm. in 

 diameter when round, and 4-15 mm. in length when elongated. When 

 fresh their colour is green, ©ccasionally pinkish, but they turn chocolate- 

 brown or dirty black on drying. The colour is due to the membrane, 

 the spore mass being always deep brown to black. On rupture of the 

 membrane the inside is found to contain a powdery black spore mass. 

 The spores are round, 6-6-12'lOjU, in diameter, dark brown, and have 

 spiny walls. 



Germination of the spores occurs easily in nutritive solutions {e.g. 

 tomato broth). The spore puts forth a thick, colourless, septate pro- 

 mycehum, and forms spindle shaped sporidia which bud very freely 

 (Fig. 2). 



The life- history of the fungus was studied in order to determine 

 whether the disease was seed-borne. A small quantity of Nachani seed 

 was infected with the spores of the smut and was divided into two lots, 

 one lot being then treated with 2 per cent, copper sulphate solution for 

 10 minutes. The two lots were then sown in separate plots. Smut 

 appeared on a few plants in the plot raised from the infected seed, while 

 in the treated plot all the plants were free from the smut. It appears 

 therefore that the smut is seed-borne and is amenable to copper sulphate 

 seed treatment. 



