Vol. VIII. No. 194. 



THE AGKICULTUKAL NEWS. 



3ir 



HOW LIME-SULPHUR WASH MAY BK 

 MADE FOR STORAGE. 



Liine-sulphur wash has been recommended by 

 this Department for several diseases, especially for the 

 ' pink-disease ' and ' thread blight,' of cacao (Pamphlet 

 No. 54, Finigus Diseases of Cacao and Sanitation of 

 Cacao Orchards ; West Indian Bulletin, Vols. VI, 

 p. 89 : IX, pp. 179-80) and for' black heart' or ' core 

 rot ' of piiie-ap[)les (Vol. VIII, p.- 163.) In addition, 

 ail account is given, in the West Indian Bidlctin, 

 Vol. Ill, p. 77, of trials of its efficac}' sxgainst the 'pine- 

 apple disease ' (due to Tlt.ielaviopsis ethaceticus) of 

 sugar-cane cuttings, while, in the same jjublication. 

 Vol. I, p. 314, it is stated that thi.s mixture (with salt 

 added) is recommended in Queensland for the general 

 treatment of fungoid pests. In Bidletin No. 92 of the 

 Pennsylv.ania State (College and Agricultural E,\-peri- 

 ment Station, auUiXad Concentrated Lime-sulphur. Its 

 Properties, Preparation and Use, an account is given 

 of experiments which were undertaken for the purpose 

 of dif-covering a w.iy in which the wash may be made 

 so that it would iKit undergo deterioration during 

 Storage. The main facts that were elucidated are as 

 follows : — 



The present !iine-.sulphur wash is generally recognized 

 as one of our most important spray material.s, both as a con^ 

 tact insecticide and fungicide. It is also recognized as one of 

 the most inconvenient and disagreeable. The advantages of 

 the wash are cheapness and wide availability of materials : 

 safety to the trees ; simplicity of preparation ; and sub- 

 stantial effectiveness, if carefully made and thoroughly 

 applied. Of all the important sprays, therefore, this one has 

 appeared to be in the most urgent need of study and revision. 



Its main shortcomings are : extreme causticity and 

 corrosion to flesh and machinery ; large amounts of sediment 

 of uncertain value : deniand for immediate application ; 

 inability to be stored, thus requiring extra labour at times 

 when men ate already bu.sy, and often involving lo.ss of 

 materials ; need for heating excessive amounts of ^^•ater ; lack 

 of ' creeping ability ': and absence of a sure and convenient 

 test for reliability of the finished spray. These iin|)erfections 

 have unquestionably greatly limited the use of this wash, 

 and we are informed that, in one of the regions where it has 

 been longest known, the present home-boiled material is no 

 longer made, having been driven out by the less troublesome 

 commercial preparations. 



These facts, together with a report of the successful 

 preparation and use of a stock solution limp-sul|ihur, led the 

 writer to undertake a careful study of lime-sulphur washes 

 with a view to reducing some of the present ditticulties of 

 their use, and if possible, to deteruuno 'the essential features 

 involved in the preparation of storable, concentrated solu- 

 tions, and . to render their preparation available to fruit 

 growers. Present experimental and commercial results indicate 

 that concentrated solutions are fully as effective as the home- 

 made dilute lime-sulphur, and are much more convenient in 

 their preparation and use. 



'ihe materials that are required for making •").") gallons of 

 • concentrated lime-sulphur are : .50 !fc. best stone lime (not 

 over 5 per cent, impurities) ; 100 lb. suljihur (flowers) : 

 '50-55 gallons of water, at finish. The method is as follows : — 



Put 10 gallons of water in a tayche or other suitable 

 Vessel and start the fire. Place the lime in the tayche. 

 After slaking is well started, add the dry suljdiur and mix 

 thoroughly, adding enough water to maintain a thin paste ; 



this will be about 5 gallons. After the slaking and mixing 

 are completed, add water to the height of 50 gallons on the 

 measuring stick, bring to a boil and stir until the suli)hury 

 scum practically disappears. Then add water (preferably, 

 but not necessarily, hot) to the 65-gallon height and boil 

 again to 55 gallons, if storage space is limited. If it is not 

 limited, a little more water should be added the third time, 

 and boiling stopped at about 60 gallons. The material 

 .should be kept well stirred especially during the early 

 stages of the proces.s, and any lumps of sulphur or lime 

 should be thoroughly broken up. 



The total time of actual boiling .should be about an hour, 

 though a teu-minute variation either way is not objection- 

 able, providing the sulphur is evidently dissolved. This fact 

 is best determined by dipping out, and slowly pouring, some 

 of the material. The amounts of water indicated abovp are 

 ample for one hour's fairly vigorous boiling, with the finishing 

 volumes as indicated. If it is not at the desired height at 

 the close, it may be made so by more water or more boiling, 

 and either the amount of water in the third addition or the 

 vigour of boiling can be so modified in later trials as to enable 

 the total to be brought to the desired height approximately 

 at the end of the hour. 



The finhshed product may be immediately poured or 

 strained into a barrel or settling tank, or into the spray tank. 

 The strc.ining is merely a safeguard to prevent anj' possible 

 clogging because of imperfect materials, or failure to break 

 lumps in the sulphur. When it is properly made, the amount 

 of sediment left in the strainer is insignificant, being less than 

 1 per cent., and may be thrown away. To avoid any consider- 

 able lo.ss of materials, however, the sediment in the strainer 

 can be washed with part of the water used in making the 

 next lot, simply pouring the water through the strainer into 

 the tayche, and any lumps of sulphur discovered may be 

 broken up and used again. 



If the straining is not done, the whole product may be 

 jiut into a settling tank or barrel, and the clear liquid drawn 

 ott' later as required. This process, however, is likely to cause 

 the loss of ethcient liquid in the sludge, as well as the fine 

 sludge itself, which may be of value in several ways, and is 

 of no apparent hindrance in the. spraying. 



The crust which forms on the finished material is 

 prevented by immediately covering the solution with a layer 

 of oil about {: inch thick, and avoiding unnecessary exposure 

 to air in the transfer from tayche to storage tank. An ordin- 

 ary kerosene oil was very satisfactory in our work, but there 

 is reason to believe that any other oil, not injurious to trees 

 nor likely to take fire at boiling temiieratures, may be used 

 with equal success. 



The crust may also be i)revented by immediate storage 

 in tight, closed vessels, filling them completely. But 

 partially filled vessels are likely to develop some crust, upon 

 continued exposure. ■ 



The concentrated solution can be diluted to any required 

 density with the aid of a hydrometer. I'^or most purposes, it 

 is efifective with a dilution of ten or twelve times. 



Carelessness in Handling- Ice Scarcely another 



article of human consumption receives so much 'direct 

 handling just before its use as ice does. Milk and water, and 

 tea and cofi'ee are poured. Puead, meat and butter are cuf. 

 Bread has a hard crust, which otters a rather unfavourable 

 lodging place for germ life. Ice, on the contrary, washes 

 the hands of every person who handles it, and affords an ever 

 ready liquid medium for the immediate absorption of the 

 hosts of bacteria which hands may carry. (The Ilawaiiaii 

 J'lantr.rs Mo»th/i/, .July 1909.) 



