POWDERY SCAB OF POTATOES. 9I 



the disease appeared to be well established in ;S0me counties. It 

 is also recorded in isolated cases in widely separated regions of 

 Canada, namely Cape Breton, Nova Scotia, New Brunswick, 

 C>ntario and Alberta. Certain observations made by Dr. I. E. 

 Melhus of the Bureau of Plant Industry in the fall of 1913 

 showed that the disease is quite widely distributed in those por- 

 tions of the Province of New Brunswick which adjoin Maine 

 and especially common in the lower St. John Valley. 



The first report of powdery scab in the United States was 

 made by the writer on May 27, 19 13, and based upon tubers 

 received some months before from Massachusetts and Nebras- 

 ka.* Almost at the same time Dr. I. E. Melhus reported the 

 disease as being found at Presque Isle, Maine t. 



Up to about February i of the present year it was suipposed 

 that the Presque Isle case, which had been traced to an impor- 

 tation of seed potatoes from Ireland two years ago, represented 

 the only occurrence of the disease in the State of Maine. 

 About this time potatoes which were being taken across the St. 

 John River for s'hipment from one oi the northern border towns 

 of Maine were found by the Canadian inspectors to be affected 

 by powdery scab, and so reported to Washington by the New 

 Brunswick Commissioner of Agriculture. Acting upon this in- 

 formation Doctor Melhus, representing the Federal Horticul- 

 tural Board, Mr. A. K. Gardner, State Horticulturist, and the 

 writer at once began a preliminary inspection of this and adjoin- 

 ing territory. This was later supplemented by Mr. Gardner so 

 as to include all the important potato growing sections of Aroos- 

 took and some of the adjoining portions of Penobscot and 

 Washington Counties. 



This preliminary inspection showed that the disease was 

 more common in the northern part o'f the county, along the 

 Canadian border. Apparently powdery scab has only recently 

 been introduiced into Maine and to date only a small percentage 

 of the farms in the section where it has been found have 

 become infested. Up to the present time it has not been re- 

 ported in the central and southern parts of the State. Storage 



* Morse, W. J. Powdery Scab of Potatoes in the United States. 

 Science 38 : 61-62. 11 JI 1913. 



t Melhus, I. E. The Powdery Scab of Potato {Spongospora solani) 

 in Maine. Science 38 : 132-133. 25 Jl 1913. 



