674 ADDITIONAL EXERCISES 



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This is used as a wash on dormant trees, for the prevention of such diseases 

 as apple scab. It must never be used on trees after the buds have burst. 

 Copper Acetate. 



Copper acetate (dibasic acetate), 6 ounces. 



Water, 50 gallons. — 



Fiist make a paste of the copper acetate by adding water to it, then dilute to 

 the required strength. Use finely powdered acetate of copper, not the crystalline 

 form. It may be used as a substitute for copper carbonate mixtures. 



Copper Saccharate. — Consult Fkeemen, E. M. : Minnesota Plant Diseases, p. 220. 



Corrosive Sublimate. 



Mercury bichloride (corrosive sublimate), 2 ounces. 

 Water, 15 gallons. 



This is an extremely poisonous mixture and should be handled with great care. 

 It is very effective against potato scab. It should not be made in tin vesseb, as it 

 corrodes them. 

 Formalin. 



Formalin (40 per cent, formaldehyd), 3-2 pound. 

 Water, 15 gallons. 



This is used in treating seed for prevention of such diseases as potato scab. 

 Iron Sulphide Mixture. — This is a new, but very promising fungicide. It was 

 tried on apples, and gave splendid results in preventing fungous diseases, being non- 

 injurious to the fruit. In preparing this fungicide, it is recommended that a self- 

 boiled lime-sulphur mixture be prepared, as later described, except that 10 pounds 

 of lime and 10 pounds of sulphur are used. The mixture is diluted to 40 gallons, 

 and then 3 pounds of iron sulphate (copperas) dissolved in about 8 gallons of water, 

 is added. 



Potassium Suipkide (Liver of Sulphur). 



Potassium sulphide, 3 to 5 ounces. 

 Water, 10 gallons. 



This is used in place of Bordeaux mixture to avoid spotting of foliage and fruit. 

 It is considered to be especially effective against powdery mildews. It is quite ex- 

 tensively used in greenhouses and on shrubbery. 



Sulphur. — Is used as a fungicide in a pure state. The flowers of sulphur is the 

 highest and usually the purest chemically. It is dusted on plants as a remedy for 

 mildew, especially the rose mildew and the powdery grape mildew. 



Sulphur and Resin Solution. — It is made up as follows: 



Sulphur (flowers, or flour), 16 pounds. 

 Resin (finely powdered), J2 pound. 

 Caustic soda (powdered), 10 pounds. 

 Water to make 6 gallons. 



Place the sulphur and resin, thoroughly mixed, in a barrel or smaller vessel, 



