104 The Spraying of Plants. 



cult are. The Bordeaux mixture proved to be most satisfactory, 

 and the following formula for its manufacture is given : 



"Dissolve 6 pounds of sulphate of copper in 16 gallons of 

 water ; in another vessel slake 4 pounds of lime in 6 gallons of 

 water." The two liquids were then slowly mixed and the 

 preparation was ready for use. This formula is the one which 

 at first was most widely recommended. 



The methods of treating the rust of melons consisted in the 

 use of a carefully prepared eau celeste, only enough ammonia 

 being added to precipitate the copper. The liquid was then 

 poured off, and ammonia added to the copper sediment remain- 

 ing in the bottom of the vessel until all the copper was again 

 dissolved. One pound of the sulphate of copper so treated was 

 sufficient for twenty-two gallons of water. Hyposulphite of 

 soda and also the sulphide of potassium were suggested for the 

 prevention of bean anthraciiose. 



Bulletin 11 of the Section of Vegetable Pathology gives an 

 account of some of the work done in the treatment of plant 

 diseases during the year 1889. In addition to the various 

 diseases which had already received attention, the following 

 are named : leaf blight of the pear and of the quince ; rusts of 

 the peach, plum, quince, and blackberry ; leaf blight of the 

 strawberry and of the blackberry ; and the rot and the blight of 

 tomatoes. In the annual report of the Section 1 additional 

 mention is made of the treatment of several apple diseases, 

 including the important experiments of Taft, Goff, and Hatch 

 on the apple-scab fungus. The account of the treatment of 

 nursery stock for the powdery mildew is also interesting. 

 Pear stock was treated for the leaf blight, and these experi- 

 ments may be considered as being the first directed towards the 

 protection of nursery stock. The nurseries of Franklin Davis 

 & Co., situated twenty miles north of Washington, were used in 

 these experiments. The following year the first applications 

 on cherry stocks were made, the disease treated being that 

 commonly known as leaf blight. In later years the treatment 

 of nursery stock became one of the leading features of the 

 work of the Section. 



It was during 1889 that the government experiment stations 

 began to report the results of work in the treatment of plant 

 * Ann, Kept, U. S. Com. Agric. 1889, 397-432. 



