2 BULLETIN 1366, U. S. DEPARTMENT OF AGRICULTURE 



BASIS AND SCOPE OF THE LIST 



The data on which this list is based have come chiefly from four 

 sources: (1) Reports of the Plant-Disease Survey collaborators in the 

 different States, (2) specimens preserved in the Pathological Collec- 

 tions of the Bureau of Plant Industry, (3) the literature on plant 

 pathology and mycology, and (4) the investigations of many special- 

 ists who have supplied information. The reports of collaborators 

 have been used principally in the work on the geographic range of 

 the various diseases. It will be seen at a glance that much more 

 information is needed on this subject, and it is hoped that all who 

 are in a position to add to our records will send reports with speci- 

 mens. The records on specimens in the Pathological Collections 

 have been used to obtain data regarding distribution. It has not 

 been possible to verify the determinations of the fungi found in the 

 herbarium, but all concerning which there was obvious doubt have 

 been omitted. The material, however, is available for examination 

 at any time in case question should arise regarding it. Records 

 from the literature on the subject chiefly relate to additional infor- 

 mation regarding the occurrence and geographic range of diseases. 



The list is confined to the diseases of the principal economic 

 plants of the United States, including most timber trees and many 

 of the ornamentals. It has been the intention to include all eco- 

 nomically important parasitic and nonparasitic diseases known to 

 occur within the continental United States. The parasitic diseases 

 are listed under each host alphabetically by causal organism. These 

 are followed by the nonparasitic diseases and those for which no 

 pathogen is known. These are indicated respectively by " nonpar." 

 and "undet." Such troubles as winter injury, frost injury, and sun 

 scald, which are liable to occur on any plant, have been omitted. 

 There are no doubt other diseases in the literature which have been 

 overlooked, and it is hoped that when such are observed they will be 

 promptly reported. 



It will be noted that the information concerning the geographic 

 distribution of many diseases is obviously incomplete. It is hoped, 

 however, that this preliminary list may stimulate more interest in 

 the subject and lead all who have an opportunity to add to our in- 

 formation to do so. It is particularly important to have plant- 

 disease material and specimens to verify the occurrence of new and 

 little-known diseases from different localities. 



HOST NAMES 



The scientific and common names of the hosts included in this list 

 are those used in Standardized Plant Names, 1 and no authority is 

 cited in connection with these names. Occasionally, necessary ex- 

 ceptions which occur in the list are shown by the use of an asterisk. 



The diseases of each host are listed separately whenever practi- 

 cable, but no attempt has been made to separate the diseases of the 

 varieties of the host species, except in a few cases where such varieties 

 include rather distinct crop plants; for example, cabbage, cauli- 

 flower, kale, kohlrabi, etc., under Brassica oleracea. 



1 American Joint Committee on Horticultural Nomenclature. Standardized Plant Names. 546 pp 

 Salem, Mass. 1923. 



