l82 DISEASES AND INSECT ENEMIES. 



of four or five inches between. This allows an 

 air space and the air in the house is sufficiently 

 warm to keep the soil in the beds next to the 

 board warm enough for root growth. 



By attending to the conditions mentioned, 

 looking carefully after watering, and seeing that 

 the soil is not too heavy, little trouble need be 

 feared from this disease. 



Oedema, or Wart Disease. This trouble often 

 proves quite serious, but is easily kept under 

 control by the proper handling of the plants. 

 The affected plants show wart-like growths over 

 the leaves and these are usually of a brownish 

 color. These warty growths vary in size, some 

 of them being quite small and others one-eighth 

 of an inch long and one-sixteenth of an inch high. 

 The corky growths are not confined wholly to 

 the leaves. In fact, they frequently occur on the 

 leaf stalks and sometimes on the flower stalks 

 also. It is found that where these warty 

 formations are developed the whole leaf is in a 

 peculiar condition. It is brittle and when taken 

 in the hand cracks very easily. The leaves, in 

 other words, instead of having a live, elastic feel, 

 appear to the touch to be dry like a shaving, and 

 when bent will break with a cracking noise. 

 Wherever a break of this kind occurs the corky 

 growth appears in time. The corky formations 

 may also develop wherever an insect punctures the 

 leaves. The punctures of aphides and the bites 



