I02 The Canadian Horticulturist. 



Prof. Scribner, whose researches in vegetable pathology have rendered his 

 name famous, has found that sulphate of copper is one of the most effective 

 fungicides that can be used. Experience has proved that this substance, modi- 

 fied as in the Bordeaux mixture and sprayed upon the grape leaves, will prevent 

 the germination of the spores of the Downy mildew which may fall upon them 

 Now there are several formulas recommended for experiment as remedies for 

 the apple scab, but they have scarcely been sufficiently tested yet for us to 

 answer our correspondent, giving him actually the cheapest and the most effective 

 one ; this much seems to be fully established, that sulphate of copper is likely to 

 prove equally effective in this case as it has been with the Downy mildew of the 

 grape. It is with the hope that our prominent fruit growers will experiment 

 with this substance faithfully in the spring, that we write at such length in reply 

 to our correspondent. The following is the course of treatment recommended : 



First, in the early spring, before the leaves appear, spray with a simple solu- 

 tion of sulphate of copper, or Eau Celeste, made by dissolving one pound of 

 sulphate of copper in twenty-five gallons of water. This is for destroying any 

 germs of the scab that may be lodged in the crevices of the bark. 



Second, as soon as the petals have fallen, and it would be no longer safe to 

 apply this strong solution, ammoniacal carbonate of copper may be applied. 

 This is prepared as follows : Three ounces of precipitated carbonate of copper 

 are dissolved in one quart of ammonia, strength 22° Baume. Dilute with 32 

 gallons of water. It will be observed that this is stronger than that recommended 

 on page 206, vol. 13. It was hoped by Professor Taft that the carbonate-of 

 copper might be applied in powder, apart from the ammonia, with equal effect, 

 and if so it could be stirred up in the Paris green water used for destroying the 

 codling moth, but it is doubtful whether it will be so effective in this form. 

 Certainly it would be very desirable to find out some formula that could be 

 safely and effectively employed in conjunction with the Paris green, for the sake 

 of economy in labor. We have it on good authority that the Bordeaux mixture 

 may be applied in this way, and, therefore, we repeat the formula for its prepara- 

 tion : Sulphate of copper, six lbs., dissolved in 4 gallons of hot water ; lime, 4 

 lbs., dissolved in 4 gallons of cold water. Mix the two solutions as above, and, 

 when desired for use, dilute to 22 gallons with cold water. 



Third, if the weather should be moist and cool, and, consequently, favorable 

 to the development of the scab fungus, it would be well to repeat the application 

 of the ammoniacal carbonate of copper once or twice during the summer months. 

 There is an objection to the use of the Bordeaux mixture late in the season, from 

 the fact that it adheres to the fruit in such a manner as to hinder its sale, unless 

 washed. 



The cost of the four applications need not be over 10 cents per tree. The 

 copper carbonate, in lots of 20 lbs., can be purchased from Messrs. Eimer & 

 Amend, 205, 1 1 Third Ave., New York, for 50 cents a pound ; or it may be 

 ordered through the local druggist at a slight advance on this cost. As this 



