CONTACT INSECTICIDES 25 



be the one just at the surface of the Hquid. When 

 the degree of concentration of the Hquid is known, 

 the proper dikition may be obtained by referring 

 to the table ^" on page 24. 



Home-made concentrated solution ^^ — The 

 concentrated solution can be made at home with a 

 fair degree of success. The lime used should con- 

 tain not less than 90% calcium oxid and not over 



C7^ 



^/C ....v^ 



ma2:nesium. The formula is as follows: 



r pure lime 36 lbs. 



Quick lime \ 95% CaO 38 lbs. 



[90% CaO 40 lbs. 



Sulphur flour or flowers of sulphur 80 lbs. 



Water , 50 gals. 



Place lime in kettle and slake with 10 gallons of 

 water. While lime is slaking add the sulphur 

 which has been previously mixed with water into 

 a paste. Stir thoroughly and when lime is entirely 

 slaked add enough water to make about 60 gallons 

 if the boiling is over an open fire. If the boiling is 

 with live steam add enough water to make 50 gal- 

 lons. Boil the mixture vigorously for one hour. 



When through, strain; store in tight containers. 

 Usually lime-sulphur will not freeze down to 5° 

 above ezro. 



For San Jose scale the diluted solution should 

 test 4.5 degrees B. ; for the blister-mite about 3.5 B. ; 

 and for summer use on foliage about i degree B. 



The concentrated solutions of lime-sulphur have 

 shown themselves to be useful against San Jose 

 scale in the summer even when diluted for use on 

 foliage. ^^ 



The self boiled lime-sulphur — This has been 



^2 Van Slyke, Bosworth, and Hedges~N. Y. State Expt. Stat., 

 Bull. 329. 



53 Parrott and Schoene— N. Y. State Expt. Stat., Bull. 330. 

 s4 Stewart — Ann. Rpt. Penn. State Coll. 1910-11, p. 268. 



