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DISEASES AND INSECT ENEMIES. 



become full of them through neglect and other 

 causes. Where the soil has not been properly 

 handled or where it is allowed to remain in use 

 for several years, nematodes are very apt to infest 



57. Nematodes, or root galls. 



it to such an extent as to become a serious pest. 

 Ordinarily, however, where the soil is changed 

 every year and where new plants are put in each 

 season the nematodes are not sufficiently numer- 



