26 INSECTS OF ECONOMIC IMPORTANCE 



found to be of use in checking San Jose scale ^^ in 

 the summer. Place 8 pounds of quick lime in a 

 barrel and start it slaking- with a small amount of 

 cold water. Work 8 pounds of sulphur through a 

 sieve and add slowly to the slaking lime. Add 

 enough cold water to slake the lime and stir con- 

 stantly. As soon as slaking is completed (s to 15 

 min.) fill barrel with cold water (50 gallons). 

 Peaches and plums can be sprayed in foliage with 

 this and the scale checked if hit when young are 

 hatching. 



Dry substitutes for liquid lime-sulphur — 

 Several commercial dry preparations are on the 

 market as substitutes for the liquid lime-sulphur. 

 Such preparations as "spra sulphur," soluble sul- 

 phur," ''dry lime-sulphur" and ''B. T. S." are among 

 those offered. Some of these are sodium-sulphur 

 compounds, some barium-sulphur compounds, and 

 some lime-sulphur compounds. They vary widely 

 in the amount of sulphur contained and are val- 

 uable, other things being equal, according to the 

 amount of sulphur each actually contains. The 

 standard liquid lime-sulphur solution {^;^'' Baume) 

 at a dilution of i to 8 for scale contains 4.75 ounces 

 of sulphur or 345% efficient sulphur per gallon. 

 The summer dilution for scab at i to 40 contains 

 1.04 ounces of sulphur or .775% efficient sulphur 

 per gallon. When the dry compounds are used 

 they should also contain an equivalent amount of 

 efficient sulphur in order to control the scale or 

 scab effectively. Manufacturers are apt to recom- 

 mend their dry materials at too low dilutions to 

 make them efficient. 



Moreover, arsenicals cannot be combined with 

 safety with those dry compounds containing so- 

 dium or potassium sulphides. 



^^ Quaintance— U. S. Dept. Agr., Yearbook 1908, p. 277. 



