CHAPTER X 

 THE PRACTICAL APPLICATION OF ECOLOGY 



Regulation of the Growth of the Crop. Time of Sowing, p. 263 ; 

 Crop Nutrition and Soil Conditions, p. 267. Resistant Varieties, 

 p. 276. 



There are many insect pests affecting agriculture which do 

 not lend themselves to direct control measures with any real 

 prospects of success. Or, the crop may be of such an extent or 

 character which renders such measures impossible from the 

 practical standpoint. Difficulties of this kind assert themselves 

 wherever agriculture is practised, but more especially in the vast 

 areas of newly developed country inhabited by backward races, 

 where insecticidal measures are usually out of the question. In 

 these contingencies, biological control may prove applicable in 

 certain cases, and this subject is fully discussed in Chapter XIV. 

 On the other hand, there are numerous instances where biological 

 control does not afford promise, or cannot be attempted. Under 

 such conditions control methods largely resolve themselves into 

 devising modifications of cultural practice as will place the pest 

 at some disadvantage and, at the same time, ensure a better crop 

 yield. In formulating such measures an acquaintance with the 

 chief ecological features in the life of a given pest in relation to 

 its plant-host is called for. Knowledge so gained, when translated 

 into practice, resolves itself into what may be termed cultural 

 methods of control. 



Cultural methods of control have definite practical advantages 

 as contrasted with physico-chemical methods. In the first place, 

 they are, as a general rule, preventive, and serve to restrain losses 

 that would otherwise supervene. Further, in the case of most 

 crops, they usually incur little or no extra financial expenditure 

 upon the practical grower, they are generally easy to apply, and 



