78 
COMBATING THE POTATO BLIGHT. 
By J. H. Bunzli. 
[Translated from Biedermanu’s Centrall-Blatt for April, 1890, by Gerald McCarthy 
N. C. Experiment Station.] 
The use of preparations of copper sulphate as a means of checking 
the potato blight has in practice proved a brilliant success. The ex¬ 
periments made by the author in the years 1887 and 1888 indicate 
clearly that potato-growers should not begrudge the small expense of 
applying the remedies if they aim at extensive cultivation of the potato 
plant. The fungicides employed in the above mentioned years were as 
follows: 
(1) Bordeaux mixture: 17 pounds 10 ounces copper sulphate; 33 
pounds lime ; 34 gallons water. 
(2) Oopper-soda solution: (a), 2 pounds 3 ounces copper sulphate; 3 
pounds 5 ounces soda; 26 gallons water; (&), 4 pounds 6 ounces copper 
sulphate; 6 pounds 10 ounces soda; 26 gallons water. 
(3) Azurin (prepared after MorgenthalePs formula). 
(4) Poudre Coignet. 
For the first treatment, made before the fiowers fell, the author used 
the preparations 1, 2a, 3, and 4, there being one plot for each solution. 
The plots were so arranged as to give to each the same exposure, fertil¬ 
ity and texture of soil. Soon after the observation was made that 
wherever the azurin was used the result was unsatisfactory. The Bor¬ 
deaux mixture gave quick results, but its manipulation was difficult. 
Under the circumstances the author concluded to use a stronger solu¬ 
tion of No. 2a, and at the second spraying of the vines employed solu¬ 
tion No. 2b. The Poudre Coignet was laid aside, as it was found to be of 
no service whatever, and besides badly burned the leaves and stems. 
Plot 1 was sprayed the second time with a dilute solution of the Bor¬ 
deaux mixture, viz: 6 pounds 10 ounces copper sulphate, 6 pounds 10 
ounces lime, and 26 gallons of water. Plot 3 received azurin again. 
This second application was given at the beginning of August, but soon 
afterward, in spite of the Azurin, the plot was found badly affected. 
Part of the plot was immediately resprayed with solution No. 2b , but 
with only partial success, because the blight had already secured such 
an advantage that it could not be dislodged. Nevertheless the supple¬ 
mentary treatment showed some effect. In each treatment the author 
aimed to use upon one acre ( juchart) 53 gallons to 79 gallons of fluid, 
put on with an efficient sprayer so that the liquids were well distributed 
on both sides of the leaves, insuring more complete adhesion and less 
risk that the material would be all washed off by the first rain. 
Although the weather was copiously moist, with the inevitable result 
of dissolving away the protective materials used, the plots treated with 
the Bordeaux mixture and copper-soda solutions were still green at the 
