CHAPTER XXIII 



METHODS OF CONTROL 



From the preceding chapters the trucker will be 

 made well aware of the many crop diseases he has to 

 deal with and of the numerous methods at hand to 

 help him to control or keep in check most of the 

 troubles. The methods of control may be classified 

 as follows: 



(i) Soil sterilization. This method has been dis- 

 cussed under Chapter IV, page 53. 



(2) Seed treatment taken up in Chapter VII. 



(3) Spraying. ^ 



(4) Crop rotation. 



(5) Development of resistant varieties. 



Spraying 



While the orchardist has learned the necessity of 

 spraying, it is doubtftil whether truckers have suf- 

 ficiently realized its value. Spraying has two aims: 

 to kiU the insect and animal pests, and to con- 

 trol fungous diseases. The substances which are 

 used for the one purpose are without effect on the 

 other. 



361 



