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The Canadian Horticulturist. 129 



5. The first manifestation of the presence of the disease is in the fall, and 

 appears as a slight swelling of the bark along the branches. A microscopic 

 examination of the tissues of these swellings reveals the presence of the myce- 

 lium of the black knot fungus Ploivrii^^htia nwrbosa. 



Query. — Why should the excrement of various insects invariably develop a 

 certain kind of fungous growth ? 



There is no better course of treatment known than that outlined by Mr. 

 Gibbs, and it would be greatly to the advantage of the fruit interests of the 

 country if orchardists would conscientiously carry out' his recommendations. 



APPLE AND PEAR SCAB (Fusicladium dentriticum). 



N order to secure the best results from spraying for this most destruc- 

 tive fungus, it is necessary to begin operations very early. Just before 

 the leaf buds open out all the trees should be sprayed with a solution 

 of copper sulphate, one pound to 50 gallons of water. This mixture 

 ^ must not be applied to the foliage itself as it would damage it very 

 much, and therefore for later applications to leaves and young fruit 



the Bordeaux inixture is commended. The latest formula, as given in Prof. 



Shutt's paper, at our last annual meeting, is as follows : 



Copper sulphate (blue stone) 4 lbs. 



Lime 4 lbs 



Water 50 gals. 



The fresh burnt lime is allowed to slake, and then well stirred, with sufficient 

 water to make a thin creamy mixture. This is now strained through coarse 

 sacking into a barrel containing the dissolved copper sulphate, and the whole 

 stirred and made up to 50 gallons. The sprayed liquor evaporates, leaving the 

 copper on the foliage as a hydrate. 



Later in the season, when the fruit is nearly full grown, and this copper 

 residue would render it unsightly, the Bordeaux mixture need no longer be used, 

 but in its place the Eau celeste, for which Prof. Shutt gave us this formula : 



Copper sulphate i lb. 



Strong Ammonia 1^/2 pints. 



Water 22 gals. 



The evaporation of this fluid leaves upon the foliage and fruit basic copper sul 

 phate and ammonium sulphate. 



The Amnioniacal Carbonate of Copper is by many jireferred to the Eau 

 celeste, and is prepared as follows : 



Copper carbonate 5 oz. 



Ammonia 2 (jts. 



Water 50 gallons, 



2 



