Page 3i 



BETTER FRUIT 



February 



PREPARATION AND USE of LIME-SULPHUR SOLUTION 



BY J. P. STEWART, EXPERIMENTAL HORTICULTURE, STATE COLLEGE, PENNSYLVANIA 



PRAYING, as applied to horticul 



ture, is just now in a state of 

 transition. This transition involves 

 the breaking away from bordeaux mix- 

 ture and the whole list of copper sprays 

 which have served for more than a quar- 

 ter of a century as fungicides and the 

 taking up of what may become an equal 

 list of sulphur sprays. It also involves 

 the abandonment of old formulas and 

 processes for making the latter sprays 

 and the substitution of more definite, 

 economical and less disagreeable meth- 

 ods. Just how complete the transition 

 will be can hardly be predicted now. But 

 this much is certain, that, whereas, two 

 years ago we might easily have told how 

 best to spray a tree, today we must wait 

 for further results before this question 

 can be finally answered. 



Among these coming sprays the clear 

 concentrated lime-sulphur solution will 

 undoubtedl}' occupy a leading place. In 

 commercial form this solution already 

 has a satisfactory insecticidal record of 

 some seven or eight years. In the new 

 home preparation it has an excellent 

 record both as an insecticide and fungi- 

 cide, being first used by Cordley of the 

 Oregon Station in 1907. Realizing the 

 importance i)f this work, in the latter part 

 of 1908, the writer undertook to deter- 

 mine the essential features of the prep- 

 aration of storable lime-sulphur solu- 

 tions, and. if possible, render their use 

 available to orchardists. 



In breif, the results of this study are 

 as follows: In the making of a storable 

 lime-sulphur at home we must first get 

 the formula right. This is accomplished 



by using one pound of good lime, one 

 containing 90 to 95 per cent calcium oxid 

 and as little magnesium as possible; two 

 pounds of sulphur and one gallon, or a 

 little more, of water; boiling it all down 

 so as to have about one gallon of total 

 product at the close. This 1-3-1 formula 

 can be made up in any quantity, merely 

 noting that the pounds of lime and the 

 gallons of final product are the same in 

 number, while the pounds of sulphur are 

 just twice as many. 



The kind of sulphur may be either 

 flour, flowers, or "powdered commercial" 

 at least 99^% pure. The last named is 

 probably" most desirable, with the flour 

 next, on account of cheapness and the 

 somewhat lessened tendency to form 

 pellets in the process of mixing. 



The utensils needed are a cooker, 

 measuring stick, strainer and hydrometer. 

 Their total cost need not exceed $15. 

 They are described in detail in our Bul- 

 letin 92 of July, 1909, so that it will suffice 

 here to say that the cooker may be of 

 either iron or wood, and use either bot- 

 tom heat or steam. If steam is used it 

 is preferable for accurate work that it 

 be in closed coils, rather than live steam, 

 at least in the latter stages of the 

 process. This is merely because it is 

 desirable that the final volume be under 

 control and be decreasing rather than 

 increasing. Steam jacketed kettles with 

 mechanical agitators are available, and 

 they work very nicely indeed. But where 

 storage is not considered and lower 

 densities are permissible there is no 

 objection to making the material with 

 the use of live steam throughout. 



In making fifty gallons of concentrate 

 the procedure is as follows: 



Materials — 50 pounds best stone lime 

 (not over 10% impurities), 100 pounds 

 sulphur (kind stated above), reduced to 

 50 to 55 gallons of total product at finish. 



Put ten gallons of water in kettle and 

 start fire. Place lime in kettle. After 

 slaking is well started add the dry sul- 

 phur and mix thoroughly, adding enough 

 water to maintain a thin paste, which 

 requires about five gallons. After the 

 slaking and mixing are completed add 

 water to the height of 50 gallons on the 

 measuring stick and bring to a boil, and 

 stir until the sulphury scum practically 

 disappears. Then add water (preferably, 

 but not necessarily, hot) to the 60-gallon 

 height and boil again to 50 gallons if 

 storage space is limited. If it is not lim- 

 ited a little more water may be added 

 the third time and boiling stopped at 

 about 55 gallons. The material should 

 be kept well stirred, especially during the 

 early stages of the process, and any 

 lumps of sulphur or lime should be thor- 

 oughly broken up. 



The time of boiling should be until the 

 sulphur granules are evidently dissolved. 

 This fact is best determined by dipping 

 and slowly pouring some of the material, 

 under close observation. In many cases 

 we have obtained as complete dissolving 

 of the sulphur in less than forty minutes 

 of actual boiling as was obtained by any 

 time up to two and a half hours. In gen- 

 eral, a period of forty to sixty minutes 

 of actual boiling should be safe and suffi- 

 cient to put the sulphur into solution. 

 But the amount of sulphites and sul- 



