174 DISEASES AND INSECT ENEMIES. 



plant will eventually succumb. When a rootlet is 

 once affected it may be destroyed and still the 

 working of the plant need not necessarily be 

 seriously interfered with. Continuous use of the 

 same soil is also a fruitful source of propagating 

 the disease. The longer the soil is used, of 

 course, the more decaying roots there will be 

 present and the more chances for infection 

 through such material. 



Summarizing, therefore, the principal ways 

 of holding this disease in check are careful at- 

 tention to the propagation of stock, extreme care 

 as to the kind of sand and soil employed, and the 

 exercise of rigid precautions in the matter of 

 examination of plants before they are finally set 

 in the beds. 



Nanism, or Stuntedness. The dwarfing and 

 stunting of a plant is not generally looked upon 

 as a disease. Nevertheless, so far as we are 

 concerned, it is a true disease because it has 

 a marked effect in reducing the income. It is 

 not uncommon to find among a number of 

 violet plants some which show quite different 

 characters from the ordinary, so far as size is con- 

 cerned. In such cases the whole plant is more or 

 less dwarfed. The leaves are small, the leaf 

 stalks are short, and the offshoots which go to 

 make up the crown are also short. When 

 such a plant blooms the flower stalks are also 

 short and the flowers in most cases are small. 



