GRAIN SMUT 411 



ground and infest the tubers. The crop may show only a little of 

 the rot due to this disease at the time of harvest, but if the tubers 

 are affected they may continue to rot in storage. If the tubers 

 show some signs of being attacked by late blight, the crop should 

 be sold or used before the disease gains great foothold and causes 

 too serious a loss. 



Potato blight of either kind may be prevented by use of Bor- 

 deaux mixture. Some growers have been successful in preventing 

 the disease by the use of lime-sulfur mixture, using the summer 

 strength. (See Chapter XXX.) Either the Bordeaux mixture or 

 the lime-sulfur may be combined with the poisons which are 

 sprayed on the plants in fighting the potato beetle, thus no extra 

 labor is required in the actual spraying work. The use of either 

 of these mixtures when combined with the poisons makes the latter 

 more effective, because it is not so readily washed off by rain. 



After potato blight has become established in the field or 

 garden there is no remedy. Spraying must be used entirely as a 

 preventive before any sign of the disease is noticeable. Several 

 applications are usually necessary, for the purpose of keeping the 

 new growth covered with the spray material. Such preventive 

 spraying has been found very profitable in many potato growing 

 sections, while in others the disease is not bad enough to warrant 

 the spraying as an annual prevention of blight. 



Grain Smut. Wheat is affected by two distinct smut diseases : 

 (1) The "stinking" smut produces a small bundle of spores in 

 place of each grain of wheat. When thrashing takes place these 

 smut balls often burst and reduce the milling value of grain, which 

 is otherwise sound. The yield is greatly reduced by the attack 

 of stinking smut. (2) Loose smut is usually less destructive to 

 wheat than to other small grains, such as barley and oats (Fig. 

 287). This fungus attacks not only the kernels but also the 

 glumes or husks surrounding them. 



Oats and barley are affected with two kinds of smut, known as 

 the covered smut and the loose smut. These are similar in their 

 appearance and growth. The spores are upon the seed at planting 

 time. When germination begins the spores also germinate and 

 attack the young plants, living in the stems, and gradually reduce 

 their vitality until time for the grain to head out. Then the black 

 spores of the disease appear in great abundance in place of the 

 healthy grain. The difference between these two smuts in indi- 

 cated by their names. Loose smut attacks both husks or chaff 



