256 AGRICULTURE OF MAINE. 



as it is now. Its presence in the United States was recorded for 

 the first time the season before by Dr. L. R. Jones in Vermont 

 on a field planted with seed tubers which came from Houlton. 

 This, as you know, is a bacterial disease of the stem and tuber. 

 It had previously been found in various parts of Europe and in 

 Canada, and is now quite widely distributed in the United 

 States. 



At the Station we have been studying blackleg in one way 

 or another ever since, but we hope that this work is now prac- 

 tically completed. Laboratory studies on the bacteria asso- 

 ciated with the disease early led to a practical means of control 

 which may be used successfully by any farmer who will do the 

 work carefully, and thoroughly. All that is necessary is to 

 entirely eliminate from the seed tubers used, all that are in 

 any way diseased or otherwise imperfect, and then disinfect 

 the remainder with formaldehyde or corrosive sublimate be- 

 fore planting. Long continued observations indicate that the 

 disease does not live over winter in the soil in Maine. Some 

 years ago it appeared on a field at Highmoor farm where two 

 dififerent lots of seed from Aroostook had been planted. By 

 careful selection, followed by disinfection with formaldehyde, 

 Mr. Sinclair entirely eliminated it and since that time not a 

 single hill of potatoes affected in this way has been observed 

 on the farm. 



Recent progress in the study of this disease in Maine has 

 been along lines of scientific and general interest, although the 

 results obtained are not without their practical bearing. Wher- 

 ever this type of disease has been studied there seems to be an 

 agreement that the general effects on the host plant are similar, 

 although certain minor dift'erences have been observed which 

 might result from local climatic or soil conditions. However, 

 investigators in Holland, Germany, Ireland and Canada had 

 made careful studies of the bacteria associated with the disease 

 and in each case recorded dififerences which led them to con- 

 sider the organism occurring in their locality as a separate 

 species. The situation was much the same as though a disease 

 like typhoid fever in man, everywhere agreeing in its clinical 

 aspects, was claimed to be caused by similar, though different, 

 species of bacteria in a number of different countries. 



