MAINE APPLE DISEASES. 385 



dilution. On the other hand, the commercial brands of lime- 

 sulphur are, of necessity, the most expensive. This is partly 

 offset in the saving in time and trouble in preparing the material. 

 All that is necessary to do with these commercial brands is to 

 dilute and apply. 



Sclf-hoilcd lime-sulphur. The self-boiled lime-sulphur is the 

 least effective in controlling apple scab according to the experi- 

 ence at this Station, but to prepare it requires no more apparatus 

 or skill on the part of the maker than in preparing bordeaux 

 mixture. 



se;i,f-boile;d lime;-sulphur, formula 3. 



Sulphur 10 pounds 



Fresh stone or lump lime 10 " 



Water 50 gallons 



To be applied without farther dilution. 

 The following is the method of preparation as described by 

 Scott* and as used by the writers in the experiments mentioned 

 on p. 349 : 



"The mixture can best be prepared in rather large quantities 

 — say 20 pounds, or even 40 pounds at a time — so as to get 

 enough heat to produce a violent boiling for a few minutes. 

 Place the lime in a barrel and pour on enough water (about 3 

 gallons to 20 pounds) to start it slaking and to keep the sulphur 

 off the bottom of the barrel. Then add the sulphur, which 

 should first be worked through a sieve to break up the lumps, 

 and finally enough water to slake the lime to a paste. Consider- 

 able stirring is necessary to prevent caking on the bottom. After 

 the violent boiling which accompanies the slaking of the lime is 

 over, the mixture should be diluted ready for spraying, or at 

 least enough cold water added to stop the cooking. Five to fif- 

 teen minutes are required for the process, according to whether 

 the lime is quick acting or sluggish. The intense heat seems to 

 break up the particles of sulphur into about the physical con- 

 dition of precipitated sulphur and the violent boiling makes a 

 good mechanical mixture of the lime and sulphur. Only a small 

 percentage of the sulphur — enough to improve the adhesiveness 

 of the mixture — goes into solution, but if the hot mass is allowed 

 to stand as a thick paste the sulphur continues to unite with the 



* Scott, W. M., Bureau PI. Ind., U. S. D. A., Cir. 27, p. 5, 1909. 



