EXPERIMENT STATION BULLETINS. 269 



found that a strong solution of copper sulphate in water, applied before 

 growth starts in the spring, will destroy the spores and the mycelium of 

 such fungi as have wintered upon the outside of the plants and, by the 

 removal of this source of infection, there will be less danger of the appear- 

 ance of the disease upon the foliage when it develops. A iceak solution 

 of the same material late in the season is in some cases desirable. Care 

 should be taken that the dilution is sufficient to prevent injury to the 

 foliage. Upon the naked branches it can be used at the rate of a pound 

 to twenty-five gallons of water, but upon the foliage one pound to two 

 hundred and fifty gallons will be sufficiently strong and, for the peach and 

 other plants with tender foliage, one half that strength, or a pound to 

 five hundred gallons, will be as strong as it will be safe to use. The clear 

 solution has the advantage over most of the other preparations of being 

 cheaper and easier to prepare, and besides it does not spot the foliage and 

 fruit. 



As it is used today the Bordeaux mixture is the favorite fungicide, as 

 it is very effective and remains for a considerable length of time upon the 

 foliage, even in seasons of heavy rains. It is a mixture of lime and cop- 

 per sulphate with water, as a result of which the copper is changed into 

 the form of hydrated oxide of copper. This is insoluble in water, and as 

 applied to the plants it is slowly rendered soluble through the action of 

 the carbonate of ammonia of the air. 



If a plant is covered with this material soon after the first leaves appear, 

 any spores of fungi that fall upon it will be destroyed as they germinate. 



It will then only become necessary to keep our plants covered at all 

 times to ward off all danger of attack. While this will be impossible, the 

 nearer we are able to approximate to this condition, the smaller will be 

 the injury. 



While the lime aids in holding the fungicide upon the plants, it can not 

 be applied to fruits within three or four weeks of the time of ripening, 

 and the fact that it renders plants unsightly is a serious objection in other 

 cases, so that, for some purposes, the adhesiveness of the material is a 

 decided drawback to its use. Not only does the lime spot the fruit and 

 render it unfit for food, but the presence of the copper and the arsenites 

 which are often used with it may, if excessive amounts are used, make it 

 positively dangerous to health. 



For all such cases the weak copper sulphate solution mentioned above, 

 or some of the ammonia solutions, may be substituted. The ammonia 

 solution of copper carbonate has many friends, for use at this time. 

 While less efficient than Bordeaux mixture or the copper sulphate solu- 

 tion in water, it has the advantage over the former of not spotting the 

 foliage. The cost, however, is considerably more than for either of the 

 other preparations. While it can be readily prepared by the dissolving of 

 commercial carbonate of copper in ammonia water, and the dilution with 

 the proper amount of water, the cost of the copper carbonate makes it 

 rather expensive. A method of preparing the carbonate of copper from 

 copper sulphate and carbonate of soda is given under "Formulas," which 

 will be but little more trouble and will reduce the cost nearly one half. 

 As thus prepared, it is the same as what is sometimes called " modified 

 eau celeste. " 



There are several other materials that are sometimes used as fungicides, 

 but none of them equal in efficiency those named above. 



