28 CROP PEST COMMISSION OF 



duced by the slaking of the lime has subsided, boiling should be 

 continued for at least thirty-five minutes, water being added 

 from time to time to keep the mixture thin enough to stir and 

 to make up for evaporation. 



After boiling for 35 minutes or more, water should In- ? Ideti 

 to make the full 50 gallons of mixture. Either hot or cold water 

 can be used for diluting. If desired, the mixture can lie iakon 

 from the kettie find placed in a barrel and the water then 

 added. The mixture should be taken immediately to the 

 orchard and sprayed upon the trees while still warm. If the 

 entire lot is not sprayed out at once, as would be the case when 

 a bucket pump is used, the mixture should be left in the ';eU>e 

 and kept at or near the boiling point until used or until the 

 day's spraying has been finished. There is no possible danger 

 of the mixture being sprayed upon the trees too hot, as the fine 

 mist from the nozzle will be lowered in temperature before it 

 comes in contact with the tree, even though the liquid in the 

 spray tank be boiling hot. The warm mixture passes through 

 the pipes and nozzles much more readily than does the cold 

 and with less liability of clogging the nozzles. In fact, when 

 this mixture is allowed to cool a large number of crystals are 

 formed.* 



These crystals can be re-dissolved by again heating the mix- 

 ture, but as a usual thing time and labor are saved by making no 

 more of the lime-sulphur mixture than will bo used during the 

 day's work of spraying. 



Where one or more barrel pumps are used and the liquid 

 sprayed out quite rapidly, two kettles are required to prepare 

 the mixture as fast as needed. One man with two 50-gallon 

 kettles can usually prepare the mixture fast enough to keep 

 two barrel pumps constantly supplied. 



When several thousand trees are to be sprayed and where 

 economy of time and labor is an important factor the use of a 

 steam boiling plant is desirable, the cooking of the mixture being 

 done in barrels or small tanks with steam, instead of in iron ket- 



"Opinions of different writers are quite at variance as to the compo 

 sition of these crystals. Prof. C. O. Hoiighton in a recent paper (Bulletin 64, 

 Del. Exp. Station) gives their composition as hydrosulphide of lime, with the- 

 chemical formula C A (SH)2- 



