82 maine: agricultural experiment station. 1907. 



attention is given to the control of this disease, and to describe 

 the methods by which it may be held in check. 



The writer has drawn largely upon the publications of other 

 stations and upon the results of his own experience and inves- 

 tigations most of which have already been published.* 



In -this connection it should be stated that this is by no means 

 the first time that this Station has called the attention of the 

 Maine growers to this disease. An examination of the files 

 shows that 19 years ago the botanist made quite an extended 

 study of the subject in an effort to determine the cause of the 

 malady and two years later he reported that its parasitic nature 

 had been demonstrated elsewhere. Additional reports were 

 made in 1893 and 1894. In the spring of 1905 a circular letter 

 was sent to the newspapers circulating in Aroostook county and 

 in 1906 a special bulletin was sent to all of the newspapers of 

 the State briefly stating the essential facts as to the nature and 

 cause of the disease, the ways in which the soil becomes infected, 

 the conditions favoring development and spread, and a summary 

 of the best methods of its control. Especial attention was called 

 to the clanger of using infected seed and to the lack of apprecia- 

 tion on the part of the growers of the importance of the disease. 



PLANTS AFFECTED BY SCAB. 



The roughened, scabby, pitted surface of potato tubers 

 affected with scab is too well known to require description. It 

 is probable that no other potato disease has a wider distribution. 

 In addition to being disseminated throughout this country it 

 occurs in various parts of Europe and different writers have 

 reported it in South Africa and New Zealand as well. It prob- 

 ably occurs wherever the potato is grown. 



In addition to the potato, beets, mangels, turnips and ruta- 

 bagas are quite susceptible to the disease. It has also been found 

 on cabbage and carrot roots and possibly may develop in a slight 

 degree on radish, salsify and parsnips. It is possible that the 

 fungus has still other hosts, for as shown later it is able to per- 

 sist in the soil for some years without the presence of any of the 

 above mentioned crops. 



(1905) 



Vt. Exp. Sta. Reps. 15, p. 225, (1902) ; 16, p. 165, (1903) ; 17. p. 397, (1904) ; 18, p. 287, 



151. 



