FUNGUS DISEASES 95 



shine, or so placed that the plants fail to get sufficient 

 moisture. In- frames the same pest abounds if much fire 

 heat is used or the matter of ventilation is treated with 

 carelessness. It will soon spread if drought is present. A 

 little sulphur applied as a powder, or mixed with water and 

 syringed on the plants, will usually check the pest, pro- 

 vided the general conditions are what they ought to be. 

 If aphides or green-fly appears in frames they should be 

 treated with occasional vapourings with one of the nicotine 

 compounds. Wire-worms are very destructive if these are 

 present in the loam. In addition to these pests there is 

 the slug, which feeds most voraciously upon the tender 

 young leaves if allowed to have its own way ; therefore 

 traps must be set, and in addition this pest must be hunted 

 for at night with a good lamp. 



FUNGUS DISEASES 



As a general rule it is the frame-grown plants that suffer 

 most from fungus diseases, but those growing out-of-doors 

 are not immune from attacks. An instance has just come 

 to the writer's notice of two collections suffering from 

 attacks of Urocystis violae. This disease causes the leaves 

 and leaf petioles to become swollen and eventually burst. 

 At first sight the condition looks as if it were the result of a 

 gall-forming insect, but when the rupture takes place the 



