238 Appendix. 



substances which will pi'event the injury. Of these combinations. I have had 

 the best results with the lime-arsenic-soda or Kedzie mixture which was first 

 recommended by Dr. R. C. Kedzie of the Michigan Experiment Station. It is 

 prepared as follows : 



2. Arsenite of Soda. 



White arsenic 1 pound 



Sal soda 4 to 5 pounds 



Water 2 gallons 



Boil together 15 minutes, or until a clear solution is formed. This stock 

 solution may be placed in jars, labeled poison, and kept indefinitely. Use from 

 1 to IU2 quarts of this stock solution and 4 to 6 pounds of freshly slaked lime 

 to each 50 galloi 3 of water. Bordeaux mixture (22 or 23) may be used to ad- 

 vantage in place of the water whenever it is desired to use a combined insecticide 

 and fungicide. 



Another method of using white arsenic is as follows : 



3. Arsenite of Lime. 



White arsenic 1 pound 



Quick lime 2 pounds 



Water 2 gallons 



Slake the lime and then boil the ingredients together for an hour. For use, 

 dilute with 300-400 gallons of Bordeaux mixture (22 or 23). I have used this 

 formula sucessfuUy but find that in this climate injury to the foliage is very 

 likely to occur unless great care be exercised in its preparation. 



4. Arsenate of Lead. 



Arsenate of soda 4 ounces 



Acetate of lead 11 ounces 



Water 25 to 50 gallons 



Dissolve the arsenate of soda in two quarts and the acetate of lead in four 

 quarts of warm water. When dissolved add them to the 150 gallons of water. 

 This formula is especially valuable for spraying very delicate foliage or for use 

 against insects which are killed only by large amounts of poison, since it can 

 be used upon plants in much stronger solutions than the other food poisons with- 

 out injury to the foliage. 



DUSTING OR DUST SPRAYIN^j. 



It is often convenient to apply poisons by dusting. Dry Paris green may be 

 so applied either pure or adulterated with various substances. If used pure it 

 should be dusted from a cloth sack of suitable texture and only the faintest trace 

 of the poison should appear upon the plants treated. One or two pounds should 

 be sufficient to treat an acre of any low-growing crop. 



To avoid using excessive and dangerous amounts of tlie poison it is usual to 

 adulterate it as follows : 



5. Paris Green. (For Dusting.) 



Paris green 1 pound 



Wheat flour or finely slaked quick lime 25-50 pounds 



Mix theingredients thoroughly and dust until the plants show a faint trace 

 of white. For dusting only a few plants use a perforated tin can or other sifter. 

 To cover a large acreage use one of the "dust sprayers" which are on the mar- 

 ket. 



The so-called "dust spray" for orchard trees is prepared as follows : 



6. Paris Green. (For Dust Spraying.) 



Paris green 1 pound 



Quick lime 10 pounds 



Water 3 quarts 



