170 THE PRINCIPLES OF AGRICULTURE 



destroy the pest in question and yet not injure 

 the plant, {b) be thoroughly done, so that no 

 part of the plant is left unprotected, (c) be 

 performed the moment the enemy appears, or, in 

 the case of fungous diseases, as soon as there is 

 reason to believe that the pest is coming. 



302. The best machine or pump is the one 

 which throws the finest spray the farthest dis- 

 tance. Other factors are the capacity of the 

 pump, its strength, its durability, its lightness, 

 the ease with which it works. 



303. Spraying will not keep all fungous dis- 

 eases in check ; and, in any case, it should be 

 supplemented by sanitation, as by burning or 

 burying the fallen diseased leaves and fruits, the 

 cutting away of infected parts, and the like. 

 Some fungous diseases, as the grain smuts, are 

 carried over from year to year in the seed ; and 

 the proper treatment is to soak the seed in a 

 fungicide. The constitutional diseases (293) 

 must be treated by other means than spraying, 

 usually by burning the affected part or plant 

 (294, 294a). 



SUGGESTIONS ON CHAPTER XI 



267a. "The daisy-cursed meadows of the East are those 

 which have been long mown and are badly 'run,' or else those 

 which were not properly made, and the grass obtained but a 

 poor start. The farmer may say that the daisies have 'run out' 



