196 DISEASES OF THE SWEET PEA 



(c) Infected Areas. In the green- 

 house, damping off or any other of the soil 

 troubles usually starts at one part in the 

 bed and from there spreads all over the 

 bed. Where only a few of these centers of 

 infection occur, much damage may be pre- 

 vented by immediately removing the in- 

 fected plants and soil from the bed to- 

 gether with the surrounding area somewhat 

 beyond the last signs of disease, 



(d) Cultural Considerations. Every 

 factor which leads to a weakening of the 

 plants should be eliminated. In the green- 

 house, overfeeding as well as underfeed- 

 ing, overwatering, and excessive high tem- 

 peratures with lack of ventilation should 

 be avoided. 



(e) Other Preventive Methods in 

 THE Greenhouse. Usually the soil in 

 the greenhouse is infected with manure, 

 with potted plants started early in a cold 



