318 Agricultural Experiment Station, Ithaca, N. Y. 



The plants were sprayed at the same time as in the preceding case, 

 and the same machinery was used. When the crop was harvested 

 it was found that 



Section 1, untreated, yielded 252 bushels per acre. 



" 2, Bordeaux mixture, yielded 298 bushels per acre. 



In this plot, the gain was 46 bushels per acre. Apparently the 

 conditions were exactly the same, and as this result corresponded 

 fairly well with the results obtained in Ithaca it may be stated that 

 spraying for the early blight is of advantage, and if the applica- 

 tions are properly made, the operation should be profitable. 



In summing up the gains obtained by spraying with fresh Bor- 

 deaux mixture for the early blight, omitting section 5 in plot III in 

 which an actual loss occurred, it is found that the average increase 

 in the four plots is 44.8 bushels, by no means an insignificant 

 amount, [n order that such results may be obtained, it is essential 

 that very thorough work shall be done, and that the operation shall 

 take place at the proper time. 



Mr. McNair also kindly furnished me with some interesting data 

 regarding the value of having plants sufficiently thrifty to with- 

 stand early blight, a subject already discussed upon page 260. He 

 found that in a certain portion of his field the addition of 10 loads 

 of barnyard manure per acre produced an increased yield of 19 

 bushels. When there were also added 100 pounds of sulphate of 

 potash and 100 pounds of Carolina rock, and the plants were in 

 addition well cultivated and sprayed, the actual increase in yield 

 was 100 bushels per acre, as was shown by an adjoining plot. 



The early blight, therefore, should be treated by growing vigor- 

 ous plants, and by protecting the foliage against the work of insects 

 and fungi by the use of the Bordeaux mixture. 



The early blight may also be avoided to a certain extent by plant- 

 ing early varieties, as these frequently mature before the blight does 

 much harm ; and also by planting late, for in this case the plants 

 will be in active growth during the season when the blight is most 

 prevalent, and it has already been shown that such plants are prac- 

 tically free from the disease. During the fall, when the plants are 

 maturing, there is less danger of attack. 



3. Potato Scab. — The remedy proposed by Bolley"^ may be con- 

 sidered as almost a specific for this disease. His first recommenda- 



*N. Dak. Agric. Exp. Sta. Bull. 4, p. 14. 



