Diseases and Injuries 



which has been recommended in Chapter XII to be used for the destruction of 

 red spider, has a greater effect in the prevention or curing of Rust than any 

 of the other mixtures I have tried. 



As a preventive against this disease, the following conditions should 

 be observed: The foliage should be free from any moisture, or condensa- 

 tion, during the night time. A free circulation of air about the plants at all 

 times should be provided. The plants should be kept in a vigorous, growing 

 condition. A close, damp atmosphere, with an abnormally high temper- 

 ature, favors the development of Rust and other fungi. Probably the most 

 essential feature in preventing these diseases is to maintain a pure atmos- 

 phere, as cool and dry as is compatible with healthy growth. 



Spraying Formulas Which Have Been Recommended as 

 Curative Agencies for Rust 



Bordeaux Mixture. — Take six pounds of copper sulphate, four j^ounds of 

 quick lime and twenty-two gallons of water. Dissolve the copper sulphate 

 in part of the water; then make a thin whitewash with the lime, to which 

 add the copper sulphate solution; then add the remainder of the water, 

 mixing thoroughly. When using this mixture, it must be thoroughly agi- 

 tated, so as to prevent the precipitation of the lime and copper sulphate. 



Ammoniacal Solution of Carbonate of Copper. — Dissolve six ounces of 

 pulverized ammonia carbonate and one ounce of copper carbonate in ten 

 gallons of water. This should be prepared as it is needed, and should be 

 thoroughly agitated during the operation of spraying. 



The following solution has also been used with good results: Dis- 

 solve one pound of sulphate of copper in two quarts of ammonia ; dilute this 

 with thirty gallons of water, and use as before described. 



Carnation Spot (Septoria Dianthi) 



This is one of the oldest carnation diseases, and possesses certain 

 characteristics by which it is easily distinguished from the other fungi that 

 attack the plant. The Spot is characterized by a circular, or oblong, brown- 

 ish center, bordered by a dark band, purplish in color. The whitish center 

 of the spot is dotted with minute, black points, which are portions of the 

 fruiting spores projecting through the epidermis to the surface. Whenever 

 the spot is on the margin of the leaf, it will be semi-circular in form. When 

 the spot extends across the larger part of the leaf, the outer portion will die. 

 On the stem, the spot appears as an oblong patch on one side, the border 



^37 



