450 IOWA DEPARTMENT OF AGRICULTURE 



WHAT IS SMUT? 



Every grower of oats is familiar with the appearance of the smutted 

 plants. Smut is a fungous plant which cannot get its own plant food 

 from the soil and water and make it into plant tissue with the aid of 

 sunlight, but must get its food supply from other plants; therefore 

 smut is a parasite. Tlhe smutted heads of oats (algo of barley and 

 wheat), are the ripened seeds or spores of the smut plant. The smut 

 seed germinates in the ground where it has been placed with the 

 seed grain and then sends its shoots up within the tissue of the grain 

 plant, feeding upon the juices of the latter. As the oat plant grows 

 and its flowers develop the smut plant steals the juices intended for 

 the developing grains and uses them to make its own seed or spores. 

 These spores are the black masses which appear in the place of the 

 seed grain and will number millions. As the smut ripens these spores 

 are blown about by the winds infecting other plants and thus contin- 

 uing in the crop year after year. 



KIXDS OF OAT SMUT 



Several kinds of smut attack small grains and treatments that are 

 effective against some neither prevent nor retard the growth of others. 

 That most commonly found in Iowa is the "loose smut of oats." and 

 this, fortunately, may be controlled by the use of formaldehyde. This 

 is likewise true of the "covered smut of wheat" which is of next im- 

 portance; this is also known as "stinking smut" or "bunt." 



The method in which the smut fungus attacks the grain plant varies 

 greatly with the different kinds. The spores of the loose smut of oats 

 ripen about the same time as the grain and become attached with the 

 seed grain either within the hull or to the outside just as do dust 

 particles. These spores may be scattered in the field by the winds or 

 during the threshing operation. When the seed germinates in the 

 spring, and smut spores placed in the soil with the oats also germinate, 

 and make their way into the tissues of the oat plant. 



SMUT IX IOWA OAT FIELDS 



The actual per cent of smutted plants was determined in 5,904 Iowa 

 oat fields in 1912 and 1913 with the results as shown in table three. 

 While 7.5 per cent of the plants were smutted in the fields where the 

 seed had not been treated, the loss in some fields was over 30 per cent. 

 The presence of 1.4 per cent of smut in the fields where the seed had 

 been treated indicates that in some cases the formaldehyde used was 

 not of proper strength or else that the work was not carefully done: 



TABLE III— SHOWING THE PER CENT SMUT IN IOWA OAT FIELDS' 



1912-1913. 



