viii PREFATORY NOTE 



It has long been known that unfavor- 

 able soil and climatic conditions and de- 

 structive insects were very important fac- 

 tors in plant culture, but it is only within 

 recent years that the public has begun to 

 appreciate that many of the diflBculties in 

 growing plants, in fact, many of the fail- 

 ures are due to diseases. Most of these 

 diseases are due to fungus or to bacterial 

 organisms. Since most of these organisms 

 are so small that they cannot be seen ex- 

 cept with the aid of a microscope, the 

 grower has usually attributed the disease 

 to other causes. The appreciation of these 

 facts makes a work on the growing of any 

 group of ornamental plants in which the 

 importance of the control of the diseases 

 is given a prominent place very desirable. 

 Therefore, this work on the Growing of 

 Sweet Peas, by a worker who has made a 

 special study of the diseases is very timely. 



