Fighting the Fungi in Their Winter Quarters, 



395 



unless the seed has been treated. The fact that the smut ripens early 

 and disappears leaving nothing but the blasted stalk at cutting time, 

 often causes the farmer to overlook its presence unless it is sufficiently 

 abundant to attract his attention from a distance. Nevertheless, the 

 careful examination of an oat field at blossoming time will usually show 

 from I to lo per cent, of smutted heads. The black sooty mass, familiar 

 to most farmers, is composed almost entirely of the minute spores of the 

 fungus. These as I have just indicated are ripened and scattered at the 

 time the oats are in blossom. When the oat plant is in bloom the two 

 glumes that enclose the grain stand wide open exposing the parts of the 

 .flower. Some of the smut spores carried over the field by the wind are 



""^SjS 



Fig. 368. — The Scab of Potatoes. 



sure to fall into this open flower and lodge at the base of the grain. When 

 the seed has been fertilized the glumes close tightly, so tightly in fact 

 that they are not removed in threshing. The smut spore is thus enclosed 

 along with the grain. When these oat grains are planted the next spring 

 the enclosed smut spores are planted along with them. The spore germi- 

 nates when the grain does, sending its germ-tube into the tender sprout 

 of the oats. This grows upward into the stalk of the plants as it lengthens, 

 finally producing its spores in the place where the grain should form. 



This disease can be entirely prevented by treating the seed with 

 formalin. Formalin is a gas dissolved in water. It can be purchased 

 atl the drug store. To 50 gallons of water add one pint of formalin. 

 Immerse the sack of oats in the solution for ten minutes or so, shaking 

 it now and then so that all the grains become wet. Remove the sack and 

 allow it to stand for two hours. The grain may then be spread out on 



