316 Agricultural Experiment Station, Ithaca, N. Y. 



The field was divided into two nearly equal parts, the line of divi- 

 sion running across the rows so that each part should contain the 

 same proportionate amount of each variety. One portion was 

 sprayed with the Bordeaux mixture, the other part remaining un- 

 treated. Applications were made July 13 and August 12, fresh 

 Bordeaux mixture being used each time. 



At the time of the second spraying a remarkable difference could 

 be seen between the two parts. The untreated portion showed fully 

 50 per cent of badly bhghted foliage, while that of the sprayed 

 part scarcely exceeded 5 per cent. This difference was especially 

 marked in case of the earlier varieties, and it could be distinguished 

 a considerable distance from the field. The untreated vines per- 

 ished earlier in the season, and when scarcely a vestige of green 

 could be found in the check section, the other portion was fairly 

 green, at least the tops appeared to possess a decided ability to 

 nourish the tubers which were dependent upon them for support. 

 At this time the very late varieties, such as the Orphan, were all of 

 a deep green color, apparently unaffected either by flea-beetles or 

 by blight. Their turn came later in the fall, although the differ- 

 ence was never so clearly defined as in the case of the earlier 

 varieties. 



These potatoes were dug during the last days of September, and 

 yielded at the following rate : 



Section 1. Fresh Bordeaux mixture, 311 bushels per acre. 

 " 2. No treatment. 272 " 



This represents a gain of 49 bushels per acre, a result appar- 

 ently due more to the prevention of the macrosporium than to the 

 destruction of the flea-beetle, for the latter was not conspicuous by 

 its absence. The fungus was very prevalent, and the vines appeared 

 to succumb rapidly when it had once gained a foothold. 



Plot III. The figures relating to the experiments in plots III 

 and IV were obtained from Mr. McNair, who very kindly looked 

 after the work in such a thorough manner that the results are here 

 published in full. The McNair farm is situated near the head of 

 the famous Genesee Valley, upon the bottom lands. The potato 

 rot is an occasional visitor, but during the summer and fall of 1895 

 practically no rot was discovered, as was also the case upon the 

 University farm, so that the beneficial results of all applications 

 must be due to the prevention of other troubles, these being com- 

 monly summed up in the term early blight. 



