Introduction ix 



however, it is felt that no apologies are due and it is 

 hoped that it will meet an important demand for 

 infonnation, and stimulate further research in this 

 line. The book is intended as a guide to practical 

 growers, teachers, students and investigators in plant 

 pathology. It is taken for granted that the practical 

 man who uses this volume will study it with a view 

 to gathering information to serve him as a guide, as 

 no definite hard rules are here laid down which could 

 apply to the problems of each individual case. It 

 is only by combining the information with good 

 common sense that the best results are to be ob- 

 tained. Constructive criticism is solicited and help- 

 ful suggestions will be gratefully received. 



Acknowledgments are here due to Dr. and Mrs. 

 D. de Sola Pool of New York City; Dr. I. Adler- 

 blum. Statistician of the Metropolitan Life Insur- 

 ance Company, New York City; Professor R. B. 

 Brackett, Professor of English of the Texas A. and 

 M. College; Professor S. C. Hoyle, Editor Exten- 

 sion Service Publicaticm, Texas A. and M. College, 

 for helpful criticisms and for reading the manu- 

 script and proofs; to Professor F. B. Paddock, 

 Entomologist, Texas A. and M. Agricultural Ex- 

 periment Statical, for reading the proofs; Miss 

 Florence Buckman of the Plant Pathology Divi- 

 sion, Texas Experiment Station for assistance in 

 preparing the glossary and the index. 



Grateful acknowledgments are further due to 

 Dr. C. G. Hopkins for fig. 2a, Dr. T. F. Maims for 

 fig. 2b, Professor L. Green for fig. 5a, Professor L. 



