No. 5.] USTILAGINE^E OF CONNECTICUT. I I 



it. In South Carolina during recent years a smut of rice has 

 been introduced from Japan, and causes some loss to this crop. 

 In the eastern states where onions are raised extensively, the 

 onion smut often does considerable injury. In this case the 

 smut becomes established in the soil and often prevents profit- 

 able onion culture on this land. Corn smut is common every- 

 where, and especially on sweet corn causes considerable injury. 

 In Connecticut the most injurious smuts, from an economic 

 standpoint, are those of onion, corn, barley, and oats. 



Prevention. With those plants where infection takes place 

 through the germinating seed, the danger usually comes from 

 the spores that mechanically adhere to the seed. It has been 

 found that, if these are killed, the crop from this seed will be 

 free from smut. Investigations have shown that certain treat- 

 ment of the grain with chemical solutions or with hot water 

 will kill the spores with little or no injury to the seed. For 

 instance, it has long been known that soaking the seed of wheat 

 in a solution of copper sulphate of a certain strength for a cer- 

 tain time serves to prevent or lessen the amount of stinking 

 smut in the crop. Later it was found that soaking the seed 

 for ten or fifteen minutes in hot water at a temperature of 

 132 to 1 35 F. was a more efficient remedy, since there was 

 less likelihood of injury to the seed. More recently still came 

 the less cumbersome practice of sprinkling piles of the grain 

 with formalin, one pint to fifty gallons of water, stirring the 

 grain to thoroughly wet it, and leaving it in piles or in bags 

 over night for the fumes to act on the spores. The smuts of 

 oats, the covered smut of barley, the stinking smut of wheat, 

 the grain smut of sorghum and broom-corn, and the grain smut 

 of millet, have all yielded to seed treatment. The loose smuts 

 of wheat and barley can be prevented or lessened by a severer 

 method of the hot water treatment (in which a preliminary 

 soaking of several hours in cold water precedes the hot water 

 treatment), but this also injures the seed more or less, so that 

 a greater quantity per acre must be sown. Corn smut can not 

 be prevented by seed treatment, as the smut gains entrance 

 through any young tissue of the host. Some experimenters 

 have advocated the removal of the smut-balls as soon as they 

 appear. It is known that the fungus develops aerial conidia 



