52 The Canadian Horticulturist. 



The plats lay side by side, running north and south. When the plants 

 were a foot high, and before they blossomed, I began to spray some of 

 them with the Bordeaux Mixture, and repeated this operation every two or 

 three weeks thereafter, until nearly the last of September. The times of 

 treatments were regulated somewhat by the weather and the frequency of 

 heavy rains. At any rate, I aimed to keep leaves and stalks on the sprayed 

 plats pretty thoroughly whitewashed with the copper sulphate solution, so 

 that its presence was always visible all over the plants. Whenever a 

 drenching rain washed off the application, it was renewed as soon as pos- 

 sible. I made the treatments with the portable Eureka spraying machine. 

 I thus sprayed Plats i and 2, left Plat 3 (the middle plat) untreated, and 

 sprayed also Plats 4 and 5. 



About the time the plants blossomed, the middle plat (No. 3) was, as 

 usual, struck by the blight, and in two weeks all of the potato tops on this 

 plat were dead and dry. The plants on the other plats were green and 

 growing as vigorously as could be wished. They remained green and 

 growing until killed by frost in November. 



I then dug and weighed separately the total product of each plat. Plat 

 No. I, sprayed with Bordeaux Mixture, yielded 346 pounds of fine large 

 marketable potatoes, which were sold as soon as dug for a dollar a bushel. 

 Plat No. 3, not sprayed, yielded only 164 pounds of small-sized tubers, 

 scarcely one of which was marketable. 



The diameter of the largest tuber on the untreated plat was three 

 inches. The diameter of the largest on the treated plat was five inches. 

 There is a marked difference in the cooking of potatoes fromthe unsprayed 

 and from the sprayed plats. Those from the plat not treated are immature 

 and " soggy." Those from the treated plats are mealy and have all the 

 excellence for which the Peachblow potato was formerly esteemed. 



I have saved ten or fifteen bushels of these Peachblows to plant next 

 year, in the confident expectation of a crop of 350 bushels of potatoes per 

 acre. Under the unfavorable conditions in which these experimental plats 

 of potatoes were grown (between rows of trees twenty feet apart and 

 twenty years old) I did not expect a large crop. Yet the yield of the 

 treated plat (No. i), 346 pounds from 225 hills, is not bad, under the cir- 

 cumstances, being about 125 bushels per acre. 



Of the Bordeaux Mixture employed the formula is : six pounds of pul- 

 verized sulphate of copper (blue vitriol), dissolved in four gallons of hot 

 water ; four pounds of fresh lime, dissolved in four gallons of cold water ; 

 mix the two solutions and dilute with cold water to make twenty-two 

 gallons of liquid. 



I believe, however, that the ammoniacal solution of carbonate of copper 

 will be found as efficient a fungicide as the Bordeaux Mixture, and it has 

 the advantage of being more readily prepared and more easily distributed 

 in spray. Its formula is: carbonate of copper, three ounces ; ammonia, one 



