1907.] PUBLIC DOCUMENT — No. 33. 1G9 



Average Yield of Hpraijed I'oUUoes. 



Average Yield 

 (Pounds). 



Wet Bordeaux, . 

 Dry Bordeaux, . 

 Copper phosphate, 

 "1 — 2 — 3," . 

 Untreated, . 



58.11 

 52.34 



55.88 

 55.46 



These results show no differences in the yield which can be 

 ascribed to spraying. Observations on the condition of the 

 crop during the summer did not show any material differences 

 except in the case of the wet Bordeaux treatment, which was 

 perceptibly superior in all respects to the others, at least dur- 

 ing the greater part of the season. The plants treated with 

 wet Bordeaux possessed the darkest-colored foliage, and were 

 by far the most free from the flea beetle. The season was 

 remarkably free from potato blights, the only thing occurring 

 of any consequence being the flea beetle ; and, with the excep- 

 tion of the wet Bordeaux, which contained Paris green, there 

 appeared to be little or no difference between the treated rows 

 and those untreated. At the time the potatoes were dug there 

 was no perceptible difference to be observed between any of 

 the rows. Owing to the season's comparative freedom from 

 blight, little or no value can be placed upon these experiments. 



The ease with which dust sprays can be applied makes the 

 process of spraying less tedious, and a dust spray which 

 possesses the merits of other reliable spra;^s on the market 

 would be gladly received. However, careful tests of the rela- 

 tive merits of the wet and dry sprays indicate that the wet 

 Bordeaux is superior in all cases to the dry. 



Our potato growers should realize that the conditions in 

 this State are entirely different from those in Vermont and 

 Maine, and the spraying calendar recommended for those 

 States is unsuited to our conditions, since their spraying is 

 largely devoted to the control of the late blight, which is 

 not generally severe here. On the other hand, it is the early 

 blight, according to our experience, which does the most dam- 



