144 EXPERIMENT STATION RECORD. 



the fungus may be found in the straw in abundance, increasing in bulk 

 as it nears the head. In general the mycelium can not be found below 

 the second internode from the head. The region most frequented is 

 that bearing the chlorophyll, and the mycelium is never found in the 

 conductive tissue. It was also found that when the smut appeared on 

 any stalk all the other stalks of that plant were affected. They may 

 all be affected and yet show no smutty heads at maturity. The stink- 

 ing smut is found to greatly decrease the growth of the straw and the 

 formation of heads. The filaments were never found in the mature 

 grain of wheat, and hundreds of sections failed to reveal the presence 

 of them after the grain had begun forming starch. It is stated that in 

 all smutted crops close observation would show that many of the grains 

 in the partially smutted heads never reach maturity, and that the 

 smutted straws in the field may be detected some time before the grain 

 is matured on account of the peculiarly modified bluish-green color of 

 the upper part of the straw. This peculiar color is thought to be prob- 

 ably due to the disorganization of the chlorophyll forming some abnor- 

 mal solution, giving a stained appearance to the cells. 



The methods of wintering the spores were investigated, and it was 

 found that spores lying over in the ground from the past year's crop 

 would readily infect the succeeding crop, and that smut may originate 

 in the new crop from volunteer wheat. 



The influence of date of seeding upon the amount of smut in the crop 

 was considered to some extent, and it was found that those conditions 

 most favorable to the wheat plant from the time of germination until it 

 is harvested are also most favorable for the growth of the smut. 



The author discusses the effect of various methods of treatment of 

 the seed grain and tabulates results of a series of experiments which 

 show the effect on germination and subsequent growth of plants of 

 corrosive sublimate, formalin, hot water, copper sulphate, sulphur 

 dioxid, and potassium sulphid when applied to wheat, oats, and barley. 



A summary is given of previous field experiments conducted for the 

 prevention of stinking smut by means of treatment with corrosive 

 sublimate, potassium sulphid, hot water, copper sulphate, formalin, and 

 corrosive sublimate to which formalin was added. The ratio of grain 

 to straw and the yield per acre and percentage of smut are shown for 

 each treatment. 



Summarizing the results of treatment for wheat in 1896 the author 

 states that under the conditions of the experiments the corrosive-sub- 

 limate treatment considerably surpassed all the other methods. When 

 hot- water treatment was used the wheat was at evident disadvantage 

 under the wet soil condition, the grain seeming to decay before the 

 plants had established themselves. Copper sulphate proved efficient 

 in preventing smut, although it somewhat reduced the yield. The 

 author states that he can not recommend the use of potassium sulphid 

 on account of its disagreeable nature and the irregular sprouting of 



