345 



DESCRIPTION OF THE FUNGUS. 



It is not the purpose of the writer of this article, in the treiitmeut 

 of the subject-matter at hand, to attempt a techuical description of the 

 fungus popularly called "stinking smut of wheat," or known scientifically 

 as TiUctla foctcus (B. & C. ) Trel. It is in order that those not acquainted 

 witli the disease may recognize it that a l)rief description is here included. 



The fungus belongs to a family of the smuts which form their spore 

 masses usually within the ovaries of various grains and grasses. In this 

 particular it differs materially from the so-called "loose smut" of oats, 

 wheat and b.-irley. The spores when mature render the seed coat brittle and 

 it is soon ruptured. The spores in dissemination become attached to tlie 

 sound seed and remain there until planted. Germination of the smut 

 spores takes place about the same time that germination of the wheat 

 kernel occurs. This is an especially favorable time for the vegetative 

 growth (mycelium) of the fungus to invade the soft tissues of the wheat 

 seedling, and their growth and development goes on simultaneously. When 

 the wheat plant has attained its growth and is forming its seed, the 

 fungus has also attained to its maximum mycelial development and pro- 

 duces its spores within the maturing kernel of the wheat. These spores 

 soon mature and form a greasy mass of dark brown color which gives off 

 a disagreeable odor if the seed coats become ruptured. They are soon 

 disseminated by various agents. 



Thus the wheat, instead of growing sound heads, produces heads 

 v/hich are light and chaify and worse than worthless, for any appreciable 

 amount of them ground together with sound seed prcxluces an unmarket- 

 able flour. They are also a very grave source of further contamina- 

 tion and infection of seed wheat. A field infected with stinking smut or 

 a bin of wheat containing a very small per cent, of stinking smut is 

 readily detected by the strong disagreeable odor it gives off. Thus it is 

 that grain dealers and elevator men instantly detect stinking smut in the 

 wheat they buy. 



PREVENTION AND TREATMENT. 



From the nature of the disease and its habit of gi-owth it is readily 

 understood that a contact fungicide should be effective in controlling this 

 disease. It has l)een conclusively demonstrated by several exi>erimental 

 workers, including the Purdue Experiment Station, that the following 

 treatment of seed wheat will entirely prevent it and at a very low cost. 



