6 BULLETIN 82, U. S. DEPARTMENT OF AGRICULTURE. 



in considerable quantity on potatoes coming from the Netherlands 

 and Belgium. As already stated, the disease has been in Norway 

 since 1SS6 and has since been found in Sweden. 



It is also interesting in this connection to note that Spongospora 

 occurs in South America, probably the native habitat of the potato. 

 It was collected in 1891 at Quito, Ecuador, by Lagorheim, who reports 

 that the disease is well known to the natives. This suggests two 

 possibilities : (1 ) That the disease has always existed there or (2) that 

 It was introduced into South America on European varieties. 



PRESENCE OF POWDERY SCAB IN CANADA. 



More recently powdery scab has gained a foothold in North 

 America, and early in the spring of 1913 it was reported in several 

 Provinces of Canada by Giissow. The writer has been able to confirm 

 Giissow's reports by personally visiting the potato-growing sections 

 in three of the Provinces of Canada, namely, New Brunswick, Prince 

 Edward Island, and Nova Scotia. It was found that powdery scab 

 was quite generally distributed in the lower St. John River valley, 

 New Brunswick, and on Prince Edward Island. 



POWDERY SCAB IN THE UNITED STATES. 



That Spongospora exists also in the United States has been defi- 

 nitely established. In the spring of 1913 Morse, of the Maine Agri- 

 cultural Experiment Station, obtained some evidence that the disease 

 exists in Nebraska and Massachusetts. No further cases have been 

 reported from these States. In June, 1913, the writer collected 84 

 tubers infected with Spongospora from four barrels of the Green 

 Mountain variet}" purchased for experimental purposes at Presque 

 Isle, Me. These had been grown in the vicinity of the village during 

 the season of 1912. 



Spongospora was collected at Washburn, Me., on February 9, 

 1914, and at Frenchville on the following day. Later it was found 

 at stations farther south in Aroostook County. 



A thorough survey of northern Maine is now being made by the 

 State department of agriculture, with the cooperation of this depart- 

 ment. The survey to date indicates that powdery scab is more 

 common in the northern half of Aroostook County. Several cases 

 were found where the growers at some time during the last three or 

 four years had secured seed from the neighboring infested sections 

 of New Brunswick, which may well account for the introduction of 

 the disease. The results secured up to the time this bulletin goes to 

 press indicate that there is considerable powdery-scab infection in 

 Aroostook County. The active measures that are now being taken 

 to discover and delimit the infected areas and to prevent the ship- 

 ment of diseased potatoes for seed purposes should result in checking 

 the spread of powdery scab. 



