CHAPTER IX 

 INSECT ENEMIES AND DISEASES 



123. Importance of controlling garden pests. The an 

 nual loss in the United States to vegetable crops from 

 the depredations of insects and diseases amounts to mil- 

 lions of dollars. Practical growers, economic entomolo- 

 gists and plant pathologists believe that most of the 

 losses could be forestalled by taking the proper preven- 

 tive measures. In too many instances, however, the 

 grower makes no preparation for control and when the 

 pests appear it is impossible to secure a spraying outfit 

 and materials before great damage has been done. 



124. Preventive measures. In the control of fungous 

 diseases and insect pests of the garden, preventive meas- 

 ures are of prime importance. Spraying is often neces- 

 sary, but it is expensive and should not be employed 

 ordinarily until all other practical means of prevention 

 have failed. Single cropping or the want of proper rota- 

 tion frequently causes trouble. When a crop pays un- 

 usually well, the temptation is to continue its cultivation 

 upon the same ground for years a practice which har- 

 bors insects and diseases. 



Diseased or infested seed or stock often introduce 

 enemies. This is a strong argument in favor of the home 

 production of seeds and plants. When plants are kept 

 in a thrifty condition there is reduced danger of serious 

 loss from both insects and diseases. Judicious fertilizing, 

 cultivating and watering may be worth far more in ward- 

 ing off attacks than any amount of spraying. Infested 

 soils when used in starting plants become a source of con- 

 tamination. Too much care cannot be exercised in the 

 selection of soil known to be free from disease germs. 



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