PREFACE xvii 



tion on cultural requirements of the par- 

 ticular crop with which they are concerned. 



Although the writer had considerable 

 experience in growing sweet peas in the 

 open and in the greenhouse, he felt that 

 this ground could be so much better cov- 

 ered by eminent specialists such as Pro- 

 fessor Beal of Cornell University; Mr. 

 CuthbertsOn, Messrs. Morse and Co., and 

 all the others who are here quoted. 



It may perhaps be the opinion of a few 

 that a book on plant pathology should not 

 include a discussion on insect pests. The 

 writer, however, believes that in a specific 

 work of this nature such a discussion is in- 

 valuable. Insects are known to be car- 

 riers of numerous plant diseases. In this 

 work it would be rather difficult to give a 

 complete discussion of Mosaic, or in fact 

 of any of the other sweet pea diseases if 

 we were to leave out of consideration the 



