198 MAINE AGRICULTURAL EXPERIMENT STATION. I914. 



grown each year up to the present. The Green Mountain, a 

 late variety, has produced some large and very satisfactory 

 crops on this farm, even in relatively dry seasons. 



There is at present a large and constantly growing demand 

 for Maine grown seed potatoes of early varieties like the Irish 

 Cobbler for southern planting. Much trouble has been experi- 

 enced in the past in getting a sufficient supply of this seed stock 

 which is free from the germs of blackleg and which does not 

 contain mixtures of late varieties like the Green Mountain. It 

 has been maintained at this Station that these difficulties could 

 be overcome by a little careful work and that once the Irish 

 Cobbler seed was freed from mixtures and blackleg it could 

 be kept pure at practically no expense. Largely for this reason 

 a change was made to the early variety for the main crop on 

 the farm and the results obtained as far as the original object 

 was concerned were entirely satisfactory. 



However, the crops of Irish Cobbler obtained, even with the 

 best of care and spraying, have been disappointing from the 

 standpoint of final yield of tubers. . As a rule this has not 

 equalled the average production for the same variety in the 

 better potato producing sections of the State and at first this 

 was attributed to the fact that the central part of the state is 

 frequently subject to a period of mid-summer drought which is 

 seldom the case in the more favored potato regions of the north, 

 which also have the advantage of a soil of greater water-holding 

 capacity. This is no doubt a contributing factor but it is by no 

 means the primary cause of the low yields as the following 

 discussion will show. 



The crops for the past two seasons were much below the 

 average, although the appearance of the fields in each case to 

 the casual observer was most promising up till a few weeks 

 before this variety would normally reach maturity. In fact an 

 experienced farmer on seeing the 19 13 field early in August 

 stated that it was the best appearing field of Cobblers which he 

 had seen that year. 



In 1912 nothing wrong was noted with the plants until the 

 tops suddenly died late in August following a period of dry 

 weather. Our attention was not called to this field until the 

 plants were practically all dead, and when examined there was 

 considerable evidence of flea-beetle injury and some early blight 



