1892.] PUBLIC DOCUMENT — No. 33. 245 



threads must reach the growing tip of the host and develop 

 with it ; thus giving no sign of their presence until the plant 

 is well grown and the heads are formed. But the growing 

 point can only be reached when the very young seedling is 

 attacked ; therefore all attacks at a late period in the life 

 of the host are soon overcome and outgrown. Now the tuft 

 of hairs or ' ' beard " and the ' ' hulls " of the grain afford veiy 

 convenient lodging places for smut spores, which are thus 

 sown with the seed, germinate with it, and are ready to 

 attack the young seedling at just the time when their attack 

 is most effectual. Besides, these spores germinate most 

 freely in fresh manure, and produce multitudes of germs 

 which can attack the host plant under favorable circum- 

 stances. As it is probable that the spores can pass through 

 the animal body unharmed, the manure from animals which 

 have eaten smutted grain must be a very important source 

 of infection. But it has been shown that the reproductive 

 power of these germs becomes exhausted in the course of a 

 year in manure ; therefore old and well rotted manure, while 

 otherwise better for the crop, is also harmless as a carrier of 

 disease. 



Professor Kellerman, formerly of the Kansas Agricultural 

 College, has estimated that in Kansas the average annual loss 

 of oats from this disease is equal to six or seven per cent, 

 of the crop, and there is no reason to suppose that this esti- 

 mate is too high for our own State. On the basis of the 

 statistics of the United States Department of Agriculture this 

 would give an annual loss in Massachusetts of $20,000 from 

 this single smut. Nearly the whole of this amount might 

 very easily be saved, if our farmers would apply the very 

 simple treatment which will certainly limit the disease to 

 an occasional stalk. This consists in soaking the seed for 

 fifteen minutes in hot water, kept at a temperature of 132° 

 F., or for twenty-four hours in a solution of one pound of 

 potassium sulphide (liver of sulphur) in twenty-four gallons 

 of water. Neither of these treatments injures the seed, but, 

 on the contrary, distinctly increases the crop. 



Of the barley smuts (Fig. 2) one seems to yield readily 

 to the same treatment, while the other seems not to be pre- 

 vented by it ; but, as both forms commonly occur on the 



