6 BULLETIN 81, U. S. DEPARTMENT OF AGRICULTURE. 



York and Boston by departmental inspectors showed the presence of 

 powdery scab in most of the arrivals from the Netherlands and in 

 many of those from Belgium and Canada. The percentage of pow- 

 dery scab varied from a trace up to 20 per cent or more. The scab 

 was usually of the superficial type, though some advanced cases were 

 found. Common scab was also present. 



It has been suggested since by the representatives of the Govern- 

 ments of the Netherlands and Belgium that these infected potatoes 

 may have originated in Germany rather than in their countries, and 

 an examination of the situation has indicated that the original quar- 

 antine order may not have provided sufficient safeguards against the 

 transshipment of potatoes from Germany and other quarantined 

 countries through Antwerp, Rotterdam, and other nonquarantined 

 ports. 



In the situation thus presented, the Department of Agriculture 

 had to determine promptly two points: (1) Is there danger that 

 diseases present on imported potatoes will become established in 

 American fields? (2) Is the powdery scab a new and dangerous 

 disease requiring exclusion by quarantine ? 



POSSIBLE INFECTION FROM IMPORTED POTATOES. 



The greater portion of the foreign potatoes imported are intended 

 for table purposes and are consumed in New York, Boston, and Phila- 

 delphia, where it has been urged that by no possibility could infection 

 reach potato fields. The facts, as determined by the Department of 

 Agriculture, are that hundreds of thousands of bushels have been 

 shipped from New York to interior points and that foreign potatoes 

 have been sold as far west as St. Louis and as far south as New 

 Orleans. This was particularly the case in 1911. There are abun- 

 dant opportunities for disease germs on potatoes used for food to 

 reach the land. Partially decayed or scabby tubers are sorted out 

 by the retailers and disposed of for feeding to five stock, and manure 

 thus infected is hauled to surrounding farms. Parings from the 

 potatoes go into the family garbage can and find their way directly 

 or indirectly to cultivated fields. 



A second avenue of infection is through the use of foreign potatoes 

 for seed. It is now fairly well known that European varieties do not 

 succeed in the United States and that the use of foreign seed is not 

 profitable, yet the number of actual instances traced by the Depart- 

 ment of Agriculture where European seed potatoes were purposely 

 planted as an experiment or through ignorance of their lack of value, 

 or where unscrupulous dealers had sold foreign stock as domestic, is 

 large enough to show that the danger from this source is a real one. 

 Canadian potatoes are valued for seed purposes and were being 

 bought in large quantities when the quarantine was laid. 



