240 AGRONOMY 



good fungicide, meanwhile removing all affected plants if the 

 disease has progressed very far. 



Sprays and spraying. The spray to be used for fungi de- 

 pends partly upon the time of the year in which it is applied, 

 and partly upon the kind of fungus to be exterminated. When 

 the plants are leafless and dormant, the lime and sulphur wash 

 is the one to be applied, while the Bordeaux mixture and the 

 ammoniacal copper carbonate solution may be used as the buds 

 begin to open and at intervals throughout the summer. As 

 yet there is no known remedy against some plant diseases. 

 Fire blight of the apple and pear, in which the branches die 

 from the tip inward as if touched by fire, is one of these. The 

 only way to save specimens attacked by it is to cut out the 

 blight a foot or more below the part affected as soon as it 

 appears. As a general thing, internal parasites are not injured 

 by sprays, though they may be kept from spreading by such 

 means. External parasites are usually killed outright. When 

 in doubt as to the proper spray to use, it is a good rule to 

 choose Bordeaux. Powdered sulphur sprinkled upon the leaves 

 is also of use, especially in combating mildew. 



Bordeaux mixture. The spray mixture adapted to the great- 

 est variety of us"es is undoubtedly Bordeaux mixture, made 

 from lime and copper sulphate or "bluestone." A standard 

 mixture consists of 5 pounds of copper sulphate, 5 pounds 

 of lime, and 50 gallons of water. To make it, the lime and 

 copper sulphate are dissolved in a little water in separate 

 receptacles, and then further diluted with about half of the 

 50 gallons before mixing. If mixed without diluting, it makes 

 a thick curdled mass that does not readily mix with the water. 

 When properly mixed the liquid should be of a brilliant, sky- 

 blue color. Three or four pounds of soap are sometimes added. 

 The lime in this mixture is chiefly used to neutralize the 

 copper sulphate, and it should always be in excess of the 

 quantity needed for this. The solution may be tested by 



