14 



treatment of apple scab 



By E. S. Gopf. 



Eecent experiments indicate that apple scab {Fusicladium dendritieum, 

 Fckl.) may be almost entirely prevented by the application of certain 

 liquid preparations, in the form of a spray, that, while harmless to the 

 foliage and fruit of the tree, are destructive to the fungus which causes 

 the disease. Yarious substances have been found to be more or less 

 beneficial, but at the present state of our knowledge, a solution of 

 copper carbonate in ammonia largely diluted with water is to be most 

 strongly recommended. Experiments conducted, the past season, in 

 the orchard of Mr. A. L. Hatch, of Ithaca, Wis., with this preparation 

 proved so far satisfactory that Mr. Hatch has decided to apply the 

 treatment to his entire orchard of about 25 acres the coming season, as 

 a means of increasing the income from his apple trees. 



DIRECTIONS FOE PREPARING AND APPLYING THIS FUNGICIDE. 



The copper carbonate and the ammonia may be procured through 

 almost any retail druggist. As the former is not always kept in stock 

 it would be well to order it some days before it is desired for use. The 

 copper carbonate should be of the "precipitated" form, and is worth 

 at retail about 65 cents per pound. The ammonia should be of a 

 strength of 22° Baum6, and should be procured in a glass or earthen 

 vessel and kept tightly corked, preferably with a rubber cork. 



Four ounces of the copper carbonate and 1 gallon of ammonia will 

 be sufiicient to give about fifty large or seventy-five medium-sized trees 

 one thorough spraying. As four or five treatments will be needed for 

 a thorough application of the remedy the amount of the materials re- 

 quired for any given orchard may be readily computed. 



The best formula that can be given in the present state of our knowl- 

 edge is to dissolve one ounce of the copper carbonate in one quart of 

 ammonia, and dilute this, when ready to commence the application, with 

 25 gallons of water. 



■WHEN TO MAKE THE APPLICATIONS. 



In the experiments made the past season in Mr. Hatch's orchard the 

 first application was made after the petals of the flowers had fallen, 

 and when the young apples were slightly larger than peas. But it is 

 the opinion of Mr. Hatch and myself that one spraying before the flowers 

 had opened would have proved beneficial. I would recommend, there- 

 fore, one treatment just before the flowers open, a second after the petals 

 have entirely fallen, and others at intervals of two or three weeks until 

 midsummer, or after, if the latter part of summer should be wet. 



