with directions for their preparation, mention also being made of tin 

 diseases for which they have been employed. 





APPLYINa THE REMEDIES. 



In applying the remedies we must consider the period and manner 01 

 the attack made by the parasite and the manner of action of the sub- 

 stance applied. Fungi living within the tissues of the host must be pre- 

 vented from gaining an entrance to these tissues ; fungi which live upon 

 the surface of plants or having their bodies soon exposed through the 

 breaking up of the epidermis, like the apple-scab fungus or the fungus 

 of bird's-eye rot of grapes, may be treated by curative methods. The 

 compounds having sulphate of copper for a base are, so far as we know 

 to-day, the best preventive remedies: sulphur, sulphur and lime, sul- 

 phide of potassium, hyposulphite of soda, are to be classed as cura- 

 tives. 



Destructive treatments are available between the periods of vege- 

 tation (winter season), and consist in destroying all infectious material 

 and in washing the plants to be protected with strong caustic solutions, 

 e. (j., solutions of sulphate of iron or copper and sulphuric acid. 



During the growing season the strength of the solutions used is gov- 

 erned by the power ot the green tissues to resist their action. In the 

 early part of the season while the shoots and leaves are yet tender, 

 weaker solutions than those which may safely be applied later in the 

 season, must be employed. There is great diversity of susceptibility 

 to the caustic action of the remedies between different species of plants 

 and even between different varieties of the same species. The condi- 

 tions of the weather at the time the applications are made may be of 

 importance in this connection. Sulphur alone, applied when the weather 

 js very hot and the sun bright, may cause a burning of the foliage. The 

 same is true of sulphatine and also of eau celeste. 



Explicit directions can not be given for these cases. Much has yet 

 to be learned by experiment, and each one must exercise judgment and 

 govern himself by surrounding circumstances. 



Avoid making the applications excessive; do not drench the plants 

 with the fluids nor plaster them with the powders. With a suitable 

 spraying apparatus, which projects a fine, mist-like spray, merely wet 

 the plant surfaces, and employ bellows which will discharge the powder 

 evenly and in such a manner that the plants may be enveloped in a 

 cloud of dust, which, settling upon all parts, becomes just percep- 

 tible. 



The necessity for good and easily-worked spraying pumps and bellows 

 is evident. For small plantations and general vineyard use, the knap- 

 sack form of sprayer, having the reservoir and pump combined, to be 

 carried on the back of the operator like a knapsack, is the best. For 

 spraying fruit trees more powerful appliances are required. 



