December i, 1882.] 



THE TROPICAL AGRICULTURIST. 



517 



MR. STOKCK ON THE TREATMENT OF 



THE COFFEE LFAP FUNGUS, 

 We call attention to the letter with which Mr. 

 Storuk of Fiji has again favoured us and in which 

 he now reconuiiends the Ceylon planters to try — not 

 10 or 25 per cent of carbolic acid, in water — but 100 

 per cent or the unmixed raw acid, in fighting the 

 coffee leaf fungus. Mr. Storck gives this advice with 

 the same confidence of success that he had in recom- 

 mending, first, a ten per cent and afterwards a 

 twenty-five per cent solution ; only he does not 

 say this time that he has akeady demonstrated the 

 absolute and final efficacy of his pi-ocess. Far from 

 it, Mr. Storck now incidentally mentions the persist- 

 ency of "the yellow spots" in shelving themselves 

 many months after it was supj50sed the remedy had 

 eradicated the disease. In other words the sporangia 

 so protect the spores that it is more difficult to 

 kill them than Mr. Storck at first supposed. Indeed 

 we cannot help thinking that our friend in Fiji is 

 only going through the slow and painful process 

 which has already been experienced by so many in 

 Ceylon, more especially since 187S-9, of finding out 

 that any merely local or temjjorary success in fight- 

 ing hemileia is no guarantee of a sufficient remedy 

 being discovered to apply to a whole country, or 

 even a coffee district, or let us say a whole plantation 

 of 200 to 250 aci-es. We would therefore advise 

 Mr. Storck not to incur the expense of a journey to 

 Ceylon until he has gained some more experience of 

 the effect of his treatment in Fiji. For, let us tell 

 him that several weeks ago we lieard of local experi- 

 ments with carbolic acid, pure and simple, in the case of 

 Liberian cofiee by a very careful experienced planter 

 who had previously tried solutions as recommended 

 by Mr. Storck up to 25 per cent without a satis- 

 factory result. We think we heard that the " raw 

 acid " was also found wanting : at any rate no news 

 has come of such a success as would warrant more 

 extended and expensive trials. While there is a 

 splendid field in Ceylon for the utilization of a cheap 

 and really effectual remedy for coffee leaf- 

 I disease, let us warn Mr. Storck that there is 

 little or no scope now — capital being so scarce 

 and every rupee on outlay having to be carefully 

 considered — for mere experimentalizing on any but 

 the most limited scale. When Mr. Storck is alile 

 to furnish the Ceylon planters with a certificate 

 signed by one (like Mr. Arthur Stephens or Mr. 

 Whitten) who knows what leaf disease in Ceylon 

 means, that he has so succeeded in keeping some 

 hundreds of acres — previously affected by hiinllcia 

 rastdl rix—onthvly free of any attack for at least 

 one year : — then we may venture to recommend him 

 to come over and supervise the application of his 

 remedy. But at present if his confidence is entu-ely 

 based on the effect of the vapour arising from pure 

 cabolic acid, we fear it will yet be disappointed 

 so far as the death and permanent eradication of the 

 spores are concerned. 



MR. STOECK ON HIS TREATMENT OF THE COFFEE-LEAF 



FUNCrS : PURE CARBOLIC ACID NOW RECOMMENDED 



FOR THE VAPOBIZkTlON PROCESS. 



Belmont, Rewa river, Fiji Island, 14th Sept. 1882. 



Deak Sir, — When I wrote to you last to give you 

 and your readers an account of a twelve-month's ex- 

 perience of the treatment of hemileia vastatrix, by 

 carbolic acid vapours, as practised and recoiamendeU 



m 



by me, I advised the use of a fluid mixture contain- 

 ing 25 per cent of acid in water as sufficient for in- 

 fallibly and thoroughly destroying that pest. I nmst, 

 however, plead guilty to having kept back wliat at 

 the time I thought a rather too sudden departure 

 from the directions given in earlier papers, and what 

 I feared might surprize and alarm, e-spocially those of 

 your readers who had akeady started or made pre- 

 parations for an earnest trial of my method : but 

 the following I hope will be accepted as an intelligible and 

 sufficient explanation for any further alterations pro- 

 jected by me. 



Any one using the above specified proportion of 

 acid will find that the sheet of water covering the 

 acid grows thinner with every application and that 

 after some 4 or 5 fortnightly supplies, there is no 

 more space left for any water, simply because the 

 periods of supply are disproportionate to the con- 

 sumption of acid, which means, in other words, tfjat 

 the vessels will be full of raw acid in direct contact 

 with the atmosphere, instead of still containing a 

 body of water which had in a way served as a screen 

 between it and the acid, rather than as a medium 

 of solution, and only permitting a certain restricted 

 amount of vaporisation. 



What I had not the boldness to recommend in 

 my last paper I do now and say: " use raiv aciil and 

 use it fearlessly, as it hurts nothiwj" \ Half a pint of 

 raw acid will in a vessel of four inches diameter 

 work and last 3 months and longer, causing au ex- 

 penditure of about 4 gallons per acre a year. Dur- 

 ing my observations of the 25 per cent charge, I had 

 for some time been thinking of reversing the pro- 

 portion of the mixture as originally recommended for 

 weekly supplies, thus containing a thin eheec of water 

 above the acid, by way of tempering the vapors arising ; 

 but, as this would have meant a resumption of the 

 troublesome weekly system, and defeated my object 

 of farther economizing labour, I came to the conclusion 

 that the boldest course is the best, and have now 

 made a clean breast of it. The alteratiou, in short, 

 consists in this; that, instead of restricting generation 

 of vapour by means of water, I now trust to dilution 

 of the carbolic fumes through the atmosphere, my 

 best ally. I was the more encouraged in introducing 

 this change, that one of the chief features of my 

 pennanent automatic system is the economy of labour, 

 as in many cases, for instance, in that of this colony, 

 it would be far easier for a man to buy chemicals, 

 a mercantile commodity, a chattle, than labour, the sup- 

 ply of which is often dependent on many contingencies, 

 artificial or natural. 



For some time past I have been thinking of an 

 improvement in the vessel as first described by me, and 

 have resolved on the following: — "Dimensions remain- 

 ing the same, the saucer receives a vertical rim J inch 

 high pierced by twelve J inch holes ; the roof, which 

 is close at the top, also receives a vertical rim, leaving 

 a slight projection for carrymg ofl' drip, and pierced in 

 such a manner that the holes in it correspond with 

 those in the rim of the saucer. With an easy fit of the 

 top part of the vessel on/- the rim of the saucer, a slight 

 turn with the hand will shut oft' an unnecessarily large 

 access of air, consequently diminishmg the generation of 

 vapour in the same ratio, even to completely stopping it, 

 and as a matter of course also the consumption of 

 material, if desired. The vessel thus combines com- 

 pactness with evei-y requisite for economy and perfect 

 control, nor need the price of it much exceed that of 

 the original. 



But before your planters go to the expense of 

 the special vessel, they may start a trial treatment 

 with anything they can procure in the way of jam tins, 

 preserve cans, wide-mouthed bottles, etc., wliilst zinc 

 or tin caseliniug, slate, shingles and similar things may 

 serve for roofing. Put the vessels on the ground with 



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