New York Agricultural Experiment Station. 209 



sprouted tubers are much more susceptible to eye injury than are 

 unsprouted ones. Many such experiments were made and the 

 results were consistent throughout. (See Table I.) The slightest 

 sprouting makes the tubers liable to eye injury. In fact, tubers 

 with sprouts one-eighth of an inch long are more liable to eye injury 

 than tubers with sprouts one-fourth to one-half inch long. Usually, 

 it can be determined within two or three days after treatment whether 

 the eyes have been injured. As a rule, injured eyes are surrounded 

 by a ring of sunken, dead, brown tissue, but there are exceptions 

 in which the eyes have been killed by the treatment yet show no 

 injury to the surrounding skin. 



Exposure to light makes the tubers more resistant to lenticel 

 spotting. In numerous cases it was observed that tubers kept in 

 a dimly lighted room for two or three weeks prior to treatment 

 showed less lenticel spotting than tubers kept in a dark cellar. It 

 was observed, also, that lenticel spotting is least severe (i. e., the 

 spots are least numerous) at the bud or seed end of the tuber. Dumb- 

 bell shaped tubers often show this in a striking manner. The tuber 

 shown in Plate II was treated in Experiment No. 5. It bore 85 

 well-marked spots on the stem-end portion while on the seed-end 

 portion there were only 20 spots and these were mostly small ones. 



The probable explanation of this is that there are fewer lenticels 

 on the seed end. 



RELATIVE SUSCEPTIBILITY OF DIFFERENT VARIETIES. 



Two crates of potatoes of the variety Rural New Yorker No. 2 

 which were in the cellar when the original treatment was made 

 showed only traces of injury while the Sir Walter Raleigh potatoes 

 were much injured. The only way in which we could account 

 for this difference was that the variety Sir Walter Raleigh is more 

 susceptible to such injury. 



In order to secure some data on the relative susceptibility of 

 different varieties the following experiments were made: In Experi- 

 ments 9 and 11 potatoes from six different groceries were compared 

 with our own Sir Walter Raleigh. It is not known to what variety 

 any of the grocery potatoes belonged, but they were probably of 

 different varieties. The severity and character of the injury varied 

 somewhat with different lots, but the differences were small. In 



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