612 ANNUAL, REPORTS OF DEPARTMENT OF AGRICULTURE. 



returned to the consignor and the remainder disposed of by consignee 

 or State officials. The number of violations by nurserymen was 

 reduced from 81 per cent in the spring of 1921 to 50 per cent in the 

 spring of 1922. The increasing effectiveness of the quarantine is 

 shown by this marked reduction in the number of violations by 

 nurserymen. Practically all violations by nurserymen are found to 

 result from neglect or carelessness on the part of nursery employees. 

 This condition has been corrected through improved methods when 

 brought to the attention of nurserymen. Violations by individuals 

 not in the nursery business are invariably committed through lack 

 of knowledge of quarantine regulations. In conducting quarantine 

 inspection work the department has received excellent cooperation 

 from the Post Office Department, common carriers, nurserymen, 

 and State officials. 



THE POTATO WART. 



The European potato wart is still restricted in the United States 

 to about 800 gardens situated entirely in mining villages in Pennsyl- 

 vania, West Virginia, and Maryland. Nearly all standard American 

 potato varieties have been tested for reaction to wart and many 

 immune varieties have been determined, so that this disease does 

 not now have the menace to this country which it originally had. 

 In the invaded districts these immune varieties are now for the 

 most part being grown under regulations enforced by the States 

 concerned and the danger from these districts is thus being very 

 greatly minimized. 



A large volume of work has been accomplished in a study of this 

 disease both from the technical standpoint of the disease itself and 

 its control and also the determination of the reaction of varieties 

 of potatoes to it as to immunity. It is proposed, after this year, 

 to discontinue much of the research work which has hitherto been 

 carried out by the board in cooperation with the Bureau of Plant 

 Industry. An appropriation for the board for the next fiscal year 

 has been asked for of only S5,000 for cooperation in quarantine 

 work and for some essential survey work. It is understood that the 

 Bureau of Plant Industry will continue such technical research work 

 in connection with the disease as may be necessary. 



The board does not feel, however, that the time has come when it 

 is either necessary or desirable to open the ports of the United States 

 to the importation of foreign potatoes from countries known to be 

 invaded by this disease. Such action would probably result in the 

 extension of this disease to practically all the potato regions in the 

 United States, and might very shortly involve a very serious conse- 

 quence where the nonimmune rural-group varieties are the main 

 dependence. 



MISCELLANEOUS QUARANTINES. 



The citrus canker and various diseases of small grains are subject 

 to foreign quarantines promulgated by the board. The local or do- 

 mestic control of these diseases is carried out by the Bureau of Plant 

 Industry in cooperation with the board. 



