Fungus Diseases of Plants 153 



disease. The agricultural experiment station bulletins 

 and special books on spraying will supply full informa- 

 tion. 



221. Diseases of Orchard Fruits, such as brown rot of 

 peaches and plums (Fig. 91); mildew and black-rot of 

 grapes (Fig. 92) and other common diseases are con- 

 trolled by spraying with Bordeaux mixture. The first 



Fig. 93. The apple scab may be prevented by spraying. 

 From Cornell University Junior Naturalist. 



spraying should be before the buds swell, and repeated 

 every few weeks thereafter until the crop is safe. 



222. Grain Smuts. The smuts of oats and wheat 

 (Fig. 87) may be prevented by treating the seed before 

 planting. The spores become lodged on the grain on the 

 hull or fine hairs. When the seetis are planted, the spores 

 germinate with the seed. It is peculiar, but true, that 

 this fungus can infect the plant only in the seedling 

 stage. Therefore, it is plain that, to prevent the blasting 

 of the oats by smut, we must destroy the smut 

 spores on the seed before planting. This may be done 

 without injury to the grain by treating the seeds with 



