206 MAINE AGRICULTURAL EXPERIMENT STATION. I9II. 



the latter part of the season, resulting in a large amount of 

 rot developing in storage and over half of the tubers were 

 sorted out as entirely decayed during the winter. The most of 

 this rot resembled that produced by Phytophthora infestans. 

 At planting time these tubers were first sorted into 2 lots, 

 those which M^ere entirely sound and those which were partly 

 decayed or were in some way imperfect. One-third of each 

 lot was exposed to formaldehyde gas, one-third treated by 

 immersing in formaldehyde solution in the usual way before 

 planting and the remainder planted without any treatment. At 

 the same time on the same field, which had not grown potatoes 

 for many years, plots of equal size were planted with healthy 

 seed tubers from 2 different sources. 



A small amount of blackleg developed on parts of the field 

 where the untreated, diseased seed was used, but the results 

 were very unsatisfactory and inconclusive. This work was 

 done at Orono, but unfortunately, the writer had very little 

 control over the experiment beyond furnishing the seed. The 

 ground allotted to the experiment was heav}'- clay, improperly 

 prepared for the crop, very dry and filled with large clods of 

 earth at planting time. The field was neglected and not prop- 

 erly cultivated- — the potatoes were at times overrun with weeds 

 and badl}^ injured by potato beetles. 



Cooperative: Experimjjnts. 



Therefore, it was thought best to ask the potato growers to 

 cooperate in testing the preventative measures outlined, on. a 

 sufficiently large scale and upon enough different farms to 

 make the combined results conclusive. This might be objected 

 to by some-as placing certain important details of the work in 

 the hands of individuals not trained in exact experimental 

 methods. Granting this objection to be valid it would simply 

 be operative in case the results were inconclusive. Un the other 

 hand if the results were comparatively clear-cut ana conclusive 

 they would be of additional value as indicating the probable 

 success or failure of the average farmer in carrymg out the 

 remedial measures recommended. Moreover those who vol- 

 unteeered to assist in carrying on these cooperative experiments 

 are specialists in potato growing and are among the most pro- 



