194 



THE CANADIAN HORTICULTURIST 



Black Knot in the Plum and Cherry 

 Plantation 



Iv. w. 



THE black knot has caused such devas- 

 tation among the plum and cherry 

 trees of Ontario that for a t;me their culti- 

 vation was almost given up. Since the 

 cause and the remedy have both been found 

 no one need fear to plant these fruits; The 

 cause is a parasitic fungus which grows 

 within the bark, and not, as many even yet 

 believe, the oviposition by some gall insect. 

 The remedy consists in cutting off and 

 burning all knots and infested branches m 

 winter or early in' the spring, before the 

 spores of the knot, which live in it over win- 

 ter, have an opportunity to develop and be 

 scattered. Many people simply cut off these 

 branches and leave them lying about. This 

 is almost as great an evil as leaving them on 

 the trees. 



Often a lot of neglected plum and cherry 

 trees in a fence corner are left undestroyed 

 in the vicinity of good trees, the owner evi- 

 dently being either too careless or too ignor- 

 ant to have them cut and burned. Such 

 clumps of neglected trees often produce 

 spores of the black knot enough to destroy 

 the orchards of a whole neighborhood. 



Where branches of valuable trees are af- 

 fected with knots which cannot be removed 

 without serious mutilation, the knots may 

 be carefully pared off with a sharp knife and 

 the wound well painted over with kerosene. 



Spraying with Bordeaux, just as the buds 

 are breaking, for rot of the fruit is very im- 

 portant, especially with plums and such 

 varieties of cherries as Black Tartarian, Elk- 

 horn, Elton, Napoleon and Yellow Spanish. 

 The sour cherries are not very subject to it. 

 Before the buds open copper sulphate may 

 be used, one pound to 20 gallons of water, 

 but this cannot be safely applied to the 

 foliage. 



Making the Bordeaux Mixture 



PROF. WM. LOCHHEAD, ONT. AGRI. COLLEGE. 



THE Bordeaux mixture is so often re- 

 commended for application in the or- 

 chard and in the small fruit and vegetable 

 garden, requests are constantly being re- 

 ceived for information as to how it is made. 

 For fungous diseases use copper sulphate 

 (bluestone), 4 pounds; lime (fresh), 4 

 pounds ; water, 40 gallons. 



In making this mixture observe the fol- 

 lowing precautions and directions : Use 

 nothing but fresh quick-lime. The lime 

 should be slowly slacked by the gradual ad- 

 dition of water. For convenience stock 

 solutions of milk of lime and bluestone 

 should be prepared and kept in different bar- 

 rels in readiness for spraying operations. 

 In barrel No. i, 25 pounds of fresh lime are 

 gradually slaked, and barrel made up to 25 

 gallons of water ; in barrel No. 2, 25 pounds 

 of copper sulphate, or bluestone, are dis- 

 solved in 25 gallons of water. For rapid 

 dissolving use warm water. These are .he 

 stock solutions. Each gallon of milk of 

 lime contains one pound of lime, and each 

 gallon of bluestone contains one pound of 

 bluestone. When we wish to make up a 

 barrel of Bordeaux mixture we take out 4 

 gallons of milk of lime and 4 gallons of 

 bluestone solution, and pour each separately 

 into the barrel in which are already 32 gal- 

 lons of water. 



Never mix the concentrated stock solu- 

 tions together. If the milk of lime and blue- 

 stone are mixed in the concentrated form, 

 just as they are taken from the stock solu- 

 tion, a precipitate of a flakey nature will 

 soon settle out, and either fall to the bottom 

 or clog the nozzle. Test the Bordeaux to 

 find out whether sufficient milk of lime has 

 been added. This is most easily done by 

 means of the ferrocyanide test. A saturated 

 solution of this substance can be purchased 

 at any druggist's for a few cents. In test- 



