INSECTS, DISEASES, AND CONTROL 283 



ably the most serious disease of tliis group. Graiu smut is 

 a serious enemy of all small grains, particularly oats and wheat. 

 Remedies. — In Chapter XI suggestons are given for pre- 

 venting potato scab and grain smut. In the preceding notes 

 regarding insects directions have been given for the prevention 

 of potato blight and tomato blight. Celery blight is prevented 

 by the diligent use of Bordeaux mixture as a spray before the 

 disease appears, or before it becomes generally spread through 

 the garden. In combating any disease it is necessary to use 



Fig. 144. — Potato with rot disease caused by late blight. (Productive Farm Crops.) 



materials as prevenUon rather than cure. Bordeaux mixture 

 is the standard preventive spray for nearly all fungous dis- 

 eases of plants. Directions for preparing Bordeaux mixture 

 are given in an exercise in this chapter. The strength for 

 summer spray on tender plants is three pounds of copper 

 sulfate (blue stone), four pounds of fresh lime to forty gallons 

 of water. This strength is known as 3 1 1 0. 



Sprayers. — The type of sprayer to use will depend largely 

 upon the size of garden, the kind of crops, and whether there 

 are fruit trees to be treated or not. The figures here shown 



