PREFACE 



The potato is one of the most important food. crops of the United 

 States. It is, moreov^er, one which is subject to a number of serious 

 plant diseases. Some of these, notably the late-blight, can be con- 

 trolled by spraying-. Yet this remedy is not applied by all farmers, 

 and the annual loss amounts to many millions of dollars. Other dis- 

 eases, like drj^-rot and the bacterial blight, are not controlled by spray- 

 ing and require a different line of treatment. The subject of disease 

 resistance in plants has received increased attention of late, and it is 

 likel}^ that the introduction of disease-resistant varieties of potatoes, 

 by supplementing- spraying and special cultural practices, will be 

 of great practical value in lessening the waste caused by disease. 

 Although but little has been done in the United States toward secur- 

 ing varieties resistant to disease, the attention of potato specialists in 

 other countries has already been directed toward this aim. 



As a preliminary step in our work, Dr. L. K. Jones, ])otanist of the 

 Vermont Agricultural Experiment Station, was counnissioned to 

 inquire into the occurrence of potato diseases abroad and the methods 

 employed for their control, particularly with reference to the produc- 

 tion of disease-resistant varieties. Doctor Jones spent six months — 

 from April to September, 1904 — in this work. 



In the course of Doctor Jones's European itinerary, information of 

 more or less value was secured at the following places, successively, 

 and this was supplemented by a considerable correspondence covering 

 a somewhat wider area: Marseille, Naples, Florence, Munich, Halle, 

 Berlin and vicinity, Dresden and vicinity, Bonn and vicinity, Wagen- 

 ingen (Holland), Amsterdam and vicinity, Groningen, Delft, Gembloux 

 (Belgium), Paris and vicinity, London and vicinity, Reading, Cam- 

 bridge, and Edinburgh and vicinity. The thanks of the Department 

 are accorded to the various officials and other botanists in the coun- 

 tries visited, whose uniform courtesies made possible the success of 

 the mission. 



As shown in this report, a considerable number of varieties are 

 reputed to be disease resistant. The best of these were selected by 

 Doctor Jones, and limited quantities of seed tubers were imported by 

 the Office of Seed and Plant Introduction and Distribution of the 



