270 CONTROLLING INSECTS AND DISEASES 



numbers of prospective pests. These agencies and factors 

 have a bearing on the situation but the grower cannot rely 

 upon them to solve his problem. 



Spraying involves the application of materials in dust or 

 liquid form to fruit plants as a preventive and combative 

 measure against the attacks of insects and disease. How- 

 ever, though the grower may resort to other measures at 

 times, his main reliance is found in the spraying program. 



Operations: 



1. Determining insects and diseases to be controlled. 



2. Selecting and preparing materials for control. 



3. Determining time of application of materials. 



4. Selecting machinery and equipment for making applications. 



5. Applying materials. 



6. Determining costs of spraying program. 



7. Adopting control measures other than spraying. 



L Determining Insects and Diseases to Be Controlled. The 



grower must know the major organisms that are destructive 

 and injurious to his fruit enterprise before he may proceed 

 intelligently with their control. 



He need not know each intimate detail of their life his- 

 tories. He may well leave such studies to the trained ento- 

 mologists and plant disease workers attached to the experi- 

 mental stations that serve his section. Certain pests, however, 

 are standard in the sense that they are present each year and 

 sufficiently serious to require control measures. Others are 

 standard but seasonal, being present and destructive only 

 under certain conditions. The grower must know these stand- 

 ard pests and the conditions governing their presence, and he 

 must be able to recognize the evidences of their presence. 



Procedure : 



(a) Consider the feeding habits of insect pests. 

 (6) Consider the nature of disease attacks, 

 (c) Consult experiment stations and other sources for com- 

 plete information. 



