SUBSEQUENT CARE OF THE PLANT 169 



and white hellebore are the materials commonly 

 used ; and worms, potato -bugs, and all leaf- 

 chewing pests, are the insects thus treated. 



298. Fungi are killed by materials which con- 

 tain sulfur or copper. Fungi which live inside 

 the leaf or stem (292) cannot be killed directly 

 by applications, but the parts which project into 

 the air (the fruiting portions) can be destroyed 

 and the fungus thereby weakened and checked ; 

 and the spores (which answer to seeds) cannot 

 grow on a surface which is covered with copper 

 or sulfur. The best treatment of plant diseases, 

 therefore, is to make the application before the 

 disease gains a foothold. A substance which is 

 used to destroy fungi is called a fungicide. 



299. The best general fungicide is the Bor- 

 deaux mixture, made of lime and sulfate of 

 copper. It not only destroys the fungi, but 

 adheres long to the plant. Another good fungi- 

 cide is carbonate of copper ; and it is preferred 

 for ornamental plants and for late application to 

 fruit, because it does not discolor or soil the 

 leaves or fruits. 



300. The application of insecticides and fun- 

 gicides is usually made in water, with a syringe 

 or pump, or by means of a spray ; and thereby 

 has arisen the practice of spraying. 



301. In order that spraying shall be success- 

 ful, it must (a) apply the materials which wilj 



