110 



Maine Agricultural Experiment Station. 1920. 



appeared on the basal leaves and afterwards on the upper ones, 

 and almost without exception was noted on the tips of the leaf- 

 lets first and then on the margins. While the whole margin might 

 be affected, the trouble was more severe and appeared first on 

 the half of the leaflet nearest the tip. In like manner the ter- 

 minal and first two lateral leaflets were attacked first and were 

 more severely affected. Fig. 22 shows a plant all of the 

 leaves of which are affected in this way. The injury was first 

 observed between two and three weeks after the plant came up 

 and the photograph was made six weeks after that. At that time 

 the two lower leaves had fallen and two more were about ready 

 to fall. 



Fig. 22.. Type of injury most common in the greenhouse. The tips 

 and margins of practically all of the leaves are affected. See also Fig. 

 26, p. 117. 



The age of the leaf seemed to be a determining factor. A 

 lower leaf might be badly affected while the leaves from a young 



