Spraying in 1890. 107 



been tried for the destruction of the black knot of plums, but 

 injury was liable to be done to the small growths, for the oil 

 spread to other places than those on which it had been applied. 

 The recommendation is therefore made that the oil be mixed 

 with some pigment to form a thin paste, and this is then to be 

 spread over the newly forming knots. Very satisfactory results 

 had followed the use of the remedy, the knots being destroyed 

 without injury to the sound tissues. The applications were 

 made with a brush. 



The Agricultural Department at Washington was conducting 

 work in the treatment of diseases of the grape, apple, pear, 

 quince, raspberry, hollyhock, and cotton. Comparative tests of 

 fungicides were also made, and a new one known as mixture 

 No. 5 was considered as having special merit. " It consists of 

 equal parts of ammoniated sulphate of copper [see page 117] and 

 carbonate of ammonia thoroughly mixed and put up in air-tight 

 tin cans." 1 It was used at the rate of 12 ounces in 22 gallons 

 of water, but this proved injurious to the foliage of cherry, 

 peach, blackberry, and young grape shoots. 



Chester, of the Delaware station, made some important 

 experiments in the treatment of grape diseases. 2 The fun- 

 gicides tested were the " ammoniated carbonate of copper," or 

 the ammoniacal solution of copper carbonate ; the carbonate of 

 copper and the carbonate of ammonia mixture, a compound 

 first used by this station, and prepared by mixing together 3 

 ounces of carbonate of copper and 1 pound of pulverized car- 

 bonate of ammonia, and then dissolving in 2 quarts of hot 

 water, after which the solution can be diluted to 50 gallons ; 

 the precipitated carbonate of copper ; the Bordeaux mixture ; 

 modified eau celeste ; and mixture No. 5, of the United States 

 Department of Agriculture. While all the conclusions drawn 

 from the work have not been fully substantiated in after years, 

 the publication did much to demonstrate the practicability and 

 financial success of proper applications of fungicides. The Bor- 

 deaux mixture was recommended as being perhaps the best to 

 use early in the season, but when danger of staining the fruit 

 arose, the use of the carbonate of copper and carbonate of 

 ammonia solution, or of the modified eau celeste, was recom- 



1 Galloway, Ann. Eept. U. S. Com. Agric. 1890, 402. See also p. 160. 

 * Del. Agric. Exp. Sta. 1890, Bull. 10. 



