40 



EXPERIMENT STATION. 



[Jan. 



As the results of last year indicated an important relation 

 between the supply of potash in available form and the preva- 

 lence of blight, it was decided to plant the field to potatoes 

 again in 1907, although it was recognized that this plan in- 

 volved considerable risk that the crop would be seriously 

 aifected by scab, since, in spite of the fact that the seed planted 

 in this field has ahvays been thoroughly treated for destruction 

 of the scab fungus, it had been noticed that the crop in a por- 

 tion of the plots was somewhat affected by this disease. The 

 amount of scab showing itself this year was unexpectedly seri- 

 ous, and this fact clearly indicates the soundness of the con- 

 clusion that potatoes should not as a rule be grown twice in 

 succession upon the same field. 



The variety of potatoes grown this year was Green Mountain. 

 The seed was treated with formalin solution in the usual man- 

 ner. On account of excessive rains throughout the early spring, 

 planting was deferred until later than usual, — May 23. The 

 crop was thoroughly cared for throughout the season, and 

 sprayed twice with different combinations of fungicides and 

 insecticides.^ The yields per plot and the rates of yield per 

 acre are shown in the following- table : — 



1 For account of spraying experiments and results, see report of the botanist and vege- 

 table pathologist, page 128. 



