INSECTS, DISEASES, AND REMEDIES 157 



There is another fungous disease that 

 causes the lower leaves of the plants to 

 die and eventually the entire plant to 

 dwindle and perish. This is called stem- 

 rot, from the fact that the fungus attacks 

 the stem and destroys the tissues or ducts, 

 thus preventing the water from ascending 

 and carrying the necessary nourishment 

 for the proper development of the plant. 

 This disease is comparatively rare. The 

 fungus apparently enters the plants from 

 the soil. The only remedy is the de- 

 struction of affected plants and as this, 

 like the other diseases noted, seldom attacks 

 strong-growing, healthy plants, the same 

 management applies. 



Powdery mildew of the chrysanthemum is 

 the most common of all fungous diseases, and 

 will attack healthy plants in greater or less 

 degree, if conditions congenial to its develop- 

 ment are allowed to exist. Sudden changes 

 of temperature, combined with excessive 

 moisture either in the soil or atmosphere, will, 

 in all probability, induce an attack. Here 

 again cultural care is the most effective 

 preventive. While the temperature of the 

 chrysanthemum house may go as low as 40 



