236 FUNGOID PESTS OF CULTIVATED PLANTS. 



In order to prevent spreading, the ergots should be collected. 

 Smith, Field Crops, p. 215, figs. 97-106 ; Sacc. Syll. ii. 5005 ; Mass. 

 PL Dis. pp. 122, 372, fig. 22 ; Cooke, Hdbk. No. 2324. 



MAIZE SMUT. 

 Ustilago Maydis (DC.), PI. XXII. fig. 15. 



The most imposing of all the smuts is that which affects Maize, and 

 attacks the ovaries so that they swell, become distended into large bags of 

 sooty powder, distorting the whole cob in an extraordinary manner. It 

 will also attack the leaves, sheaths, and male flowers. 



The spores are soon powdery and nearly black in the mass, globose, or 

 nearly so (8-13 x 8-11^), with the surface sightly rough. On germina- 

 tion the promycelium is cylindrical and comparatively thin, producing 

 oblong fusiform sporidiola, or secondary spores. It is chiefly by means of 

 these secondary spores that the disease spreads so rapidly. Inoculation 

 takes place originally from spores that remain over a year in the soil, or 

 secondary spores which continue to reproduce themselves by germination. 



Appears to occur wherever Maize is cultivated, and plants may be 

 inoculated at any age. 



It is known in Britain, France, Belgium, Germany, Austria-Hungary, 

 Italy, North America, and Chili. 



It has been observed to be most abundant where fresh manure has 

 been used. 



Sacc. Syll, vii. 1723 ; Mass. PL Dis. p. 213 ; Cooke, M. F. p. 230, 

 fig. 108 ; Cooke, Hdbk. No. 1525 ; Plowr. Brit. Ured. p. 278. 



POWDERY MAIZE SMUT. 

 Ustilago Beiliana (Kulm), PI. XXIII. fig. 16. 



This smut occurs on the male florets of Maize, and was first observed 

 by us on specimens sent over from Lahore (India) and called Ustilago 

 pulveracea, but it was afterwards discovered to have had a prior name, 

 as above, and made its appearance in Britain and other parts of 

 Europe. 



The pustules are formed in the inflorescence, at first enclosed in a silvery 

 membrane, then becoming powdery, blackish-brown. Spores subglobose, 

 and delicately rough on the surface (9-12/z diam.), clear brown. Promy- 

 celium on germination septate, producing elliptical sporidiola, or secondary 

 spores. It has been demonstrated that the spores will germinate after a 

 period of eight years. 



This species has been found in Britain, Italy, Germany, Hungary, 

 Egypt, and N.W. India. 



All that can be done is to prevent its spreading by consuming all the 

 diseased parts, and spraying to prevent the germination of any scattered 

 spores. 



Sacc. Sijll. vii. 1720 ; Grevillca, iv. 1876, p. 115 ; Mass. PL Dis. p. 402. 



