BOUILLIE BOEDELAISE. 257 



these organs there exists an admu'able correlation when they are 

 intact, but as soon as one of these cannot fulfil its physiological 

 functions, the other suffers. If the leaves are killed by parasitic fungi 

 the roots cannot do their part. The sap which ascends, however rich 

 it may be, cannot nourish the plant if this sap is not elaborated by the 

 leaves ; respiration is affected, assimilation is defective, the alimentation 

 of the different organs of the plant by the descending sap is inefficient ; 

 if the leaves fall or are entirely destroyed life ceases. It is therefore 

 important to prevent all wounds on the leaf, to stimulate their develop- 

 ment, and to keep them as long as possible in a state of health. 

 That is realizable if the many sprayings with bouillie bordelaise are 

 included in the necessary and normal dressings of fruit trees, as in 

 the orchards of Sweden and America. A tree regularly and systemati- 

 cally treated with bouillie bordelaise keeps its leaves healthy. By its 

 stimulating effects cupric hydrate prolongs the vitality of the leaves 

 until late in the season, and the growth of the trees being thus pro- 

 longed, become more vigorous than those which have not undergone 

 this treatment. The amount of copper required to produce this re- 

 markable physiological effect is almost infinitesimal, and the bouillies 

 used need not be prepared with more than 0"5 per cent of blue vitriol. 

 Fruit trees being very sensitive to pure blue vitriol, it is necessary 

 that the bouillie bordelaise be prepared with great care. 



Fusicladium Cerasi, Sacc. (black spots of the cherry). — Sirodot 

 recommends the treatment and precautions used against apple and 

 ppar spots. 



Entomosporium maculatum (leaf scald of pear and quince tree) ; 

 Entomosporium Mespiii, Sacc, or Morthiera Mesjnli, Fuckel (spots of 

 the leaf of the pear). — The fruit trees are treated as indicated for 

 Fusicladmm. Galloway, Pearson, Chestei-, Sturgis have made several 

 trials in this direction. They show that by several sprayings annually 

 the ravages of this fungus may be prevented. In the beginning a, 

 3 per cent bouillie of blue vitriol and 2 per cent of lime was used ; 

 but it was found that weaker bouillies are capable of rendering the 

 same service. Maxwell obtained the following results with a 2 per- 

 cent bouillie : — 



TABLE L. — Showing the Effect of Repeated Spraying with a 2 Per Cent. 

 Bouillie Bordelaise on the Percentage of Diseased Pear-Tree Leaves. 



Percentage of 

 Diseased Leaves. 



Untreated trees 75-84 



Twice treated trees, 25 April, 9 May 3-17 



Three times treated trees, 14 April, 25 April, 9 May . . 3-17 



Seven ,, „ „ 14 April, 25 April, 9 May, 5 June, 



25 June, 14 July, 5 August . . 0-00 



To prevent great damage two sprayings suffice ; but the disease is 

 not entirely stopped until after multiple treatments. Waite advises 

 a single treatment at the right time, that is to say, when the leaves 

 are two-thirds of their normal size. Fairchild lowered the strength 

 of the bouillie to 1'2 per cent of blue vitriol and as much lime, and 

 obtained the same favourable result by repeated sprayings as with. 



17 



