New York Agricultural Experiment Station. 189 



those most exposed on the surface of the top crates. The injury 

 appeared in the form of sunken brown spots of various shapes and 

 all sizes from a mere speck to about one-half inch in diameter. 

 Sometimes larger spots were formed by the coalescence of two or 

 more small spots. Many spots were circular with a lenticel at the 

 center. Frequently, the eyes were surrounded by circular sunken 

 areas of brown dead tissue. On many tubers as much as one-half 

 of the total surface area was covered by the spots. Although the 

 spots, particularly the larger ones, were conspicuously sunken, the 

 layer of dead, brown tissue lining the depression was usually only one 

 or two millimeters in thickness, it was rarely more than 3 milli- 

 meters thick. In one of the top crates containing 213 tubers 56 were 

 so much injured as to be unfit for seed. In another top crate 67 per 

 ct. of the tubers were more or less spotted while in the crate just 

 beneath only 12 per ct. were spotted. The tubers in the entire 40 

 top crates were carefully sorted and 10 bushels, or 25 per ct., which 

 showed more or less eye injury were rejected as unfit for seed. 

 Apparently, the tubers in the lower crates were not sufficiently 

 injured to materially affect their germination. However, it should 

 be stated that where these potatoes were planted a very poor stand 

 was obtained. This, we believe, was due to unfavorable soil and 

 weather conditions rather than to any weakness of the seed. Even 

 the worst-affected tubers were only slightly injured for culinary 

 purposes, yet their disfiguration would certainly have affected their 

 salability. They showed no tendency to rot and the spots did not 

 increase in size or depth. 



It was decided to make an inquiry into the cause of the injury. 



METHODS OF INVESTIGATION. 



The season was so far advanced when the investigation was 

 begun that it was impossible to do much experimental work in the 

 spring of 1912. Three experiments were made during May and then 

 the work was discontinued until January 30, 1913, when it was again 

 taken up and pursued actively until May 26. Three additional experi- 

 ments were made in the fall of 1913. The total number of fumigation 

 experiments made was 89. The fumigation chamber was a wooden 

 box of 21.56 cubic feet capacity. Its inside dimensions were 34.5 x 

 36 x 30 inches. It was constructed of well-seasoned matched lumber 



