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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