March i. 1883.] 



THE TROPICAL Aq|gLlCULTURIST. 



721 



To the Editor of the Ceylon Observer. 



COFFEE LEAF-DISEASE : THE EXPERIMENTS 



WITH CARBOLIC ACID AT UDAPOLLA : SOME 



FACTS FOR MR. STORCK. 



UdapoUa, Polgahawela, 3rd Feb. 1883. 



Dear Sir, — In your yesterday's issue in a foot-note 

 to " Enquirer " on the subject of StorcU's carbolic 

 acid treatment for coffee leaf-disease, you say, and 

 truly, you think I have lost faith in it as a remedy. 

 For the information of " Enquirer "and othei'S I give 

 the result of the trial made here. In May 1882 

 Messrs. Leechman sent up a cask of carbolic acid 

 wii\i properly constructed tin utensils, and instructions 

 as to the method of carrying on the experiment. On 30th 

 May, as many as 76 tins were laid down at 40 feet apart 

 each way to serve two acres of coffee, and tilled with 

 a 10 per cent strength of acid with water, and these were 

 replenished from time to time with same strength 

 mixture. Ou '21st June the strength of the solution 

 was raised to 2,5 per cent and tlie tins refilled every 

 three days till 16th October, when the strength of 

 the mixture was increased to 50 per cent. Besides 

 the two acres thus treated there were eight trees 

 with a tin to each, filled with the same strength of 

 acid as the others ; and at the end of October these and 

 other twelve tins were filled full with pure carbolic 

 acid. It would occupy too much space to make ex- 

 tracts from my diary as to the condition of the trees 

 from time to time ; sufiSce it to say that at all strengths 

 the results were nil. At any time, from the commence- 

 ment to the present, the disease could be found on 

 these trees in varying stages. So lately as this morn- 

 ing I found beautiful, healthy, red spores on leaves 

 within a yard of utensils containing pure acid. It is 

 my belief that the acid has no effect upon the disease. 

 Surely there has been an atmosphere of the acid 

 fumes surrounding these trees long enough to have 

 shewn some result, if it were ever going to do it. 

 The disease has shown itself and fruited many times 

 within the eight months, whereas, according to Mr. 

 Storck, the trees should be quite clean, he asserting 

 that in an atmosphere of carbolic acid the disease 

 cannot be developed. " No live spores can be carried 

 out of the area under treatment — nothing carried in 

 can live, and re-infection becomes impossible." I can- 

 not help thinking that all Mr. Storck's cures were 

 effected naturally ; and trees not under treatment 

 would have recovered equally with those under it. 

 During August and September last leaf-disease was 

 very bad ; worse than in any previous year, mainly, 

 1 believe, owmg to the character of the season ; mild 

 showers and sunshine alternating, making a veritable 

 steamy hothouse Since October the disease has de- 

 clined, and at the present time there is veiy little ; 

 the trees are ripening up a heavy crop, and there 

 is a fine blossom-spike which will open in about four 

 days. One peculiarity of leaf disease in Liberian coffee 

 is that it attacks the berries ; the germinal tubes 

 enter the cherry skin (how I do not know) from 

 mycelium, which fruits abundantly, causing gi'eat 

 damage to fruit only half matured, and even to those 

 much farther advanced. This in my experience has 

 never occurred to Arabian coffee, though I see by a 

 letter from an Indian correspondent in yesterday's 

 issue of your paper, that he says leaf-disease is so 

 bad that the berries are covered with the ■ ed rust 

 from the leaves, which causes damage to tlie fruit. 

 If he observes carefully 1 think he will find that tlie 

 rust is developed from the fruit itself : at any rate 

 it Is 30 with Liberian coffee. Mr. Marshall Ward says: — 

 ' ' I find no trace of tlie mycelium in any other 



part of the plant than the leaf," and with this I 

 think your correspondent " W." agi'ees ; for when 

 another writer suggested that the mycelium might 

 do harm through the roots, he said it could not, as 

 the roots of plants have no stomata, and therefore 

 the germinal tubes cannot find an entrance. I do 

 not know whether the tough green skin or husk of 

 Liberian berries has stomata or not, but I should 

 like to know, and perhaps your clever and facile cor- 

 respondent ■' W." will kindly inform us. Hemileia 

 spores will not grow upon the upper side of a leaf, 

 and I should have thought the cherry skin a tougher 

 substance than it. — Yours truly, 



WILLIAM JARDINE. 



THE COFFEE FUNGUS AND PLUCKING OFF 

 LEAVES. 



Sir,— An experiment somewhat similar to that 

 proposed by your correspondent, Mr. Kearney, has 

 been undertaken at my inst.-inoe in several places for 

 some mouchs past ; and in due time the results 

 if found to be of any use or interest, will be pub- 

 lished. The method I have adopted is to pluck nil 

 fully matured leaves indiscriminately, whether diseased 

 or not, immediately on their attaining the full size 

 and dark colour of mature growth. The experiments 

 were initiated in order to ascertain the effect of such 

 treatment on the health of the tre- — on its fruit- 

 bearing power — and on the leaf-disease. The object 

 was chiefly in connexion with the functions of leaves 

 and thiir work. The experimenta will therefore have 

 a special interest apirt from any connexion with 

 Hemileia. I may mention that, so far, the results 

 have been rather remirkable The trees and plants 

 so plucked have more foliaga than their neighbours 

 that are not plucked or otherwise treated. 'This re- 

 sult; contmues after .several months' persistent pluck- 

 ing. The f(iliaf;e is of course fresher, and tlieiefore 

 the trees in sto far have a liealthier appearance The 

 present is n cntical stage of the experiments, as it 

 is that in which the effect of the treatment on the 

 blossoming and fruiting of the trees will be manifested. 



The plucked trees have about the same amount 

 of .ipike lis their neighbours, and unfortunately this 

 weather is so unfav mrable tn all spike that little can 

 yet be said of the promise of this in particular. The 

 experiments will be pursued till the effect ofpluckinw 

 can be seen through the formation iind matuiino- o1 

 the fruit. The effect on leaf-disease is, of course," to 

 prevent any severe outburst, as all the leaves that 

 become affected are plucked in common with the others 

 before the disease attains maturity. Tne cost of the 

 work h.as yet to be ascertained, as it has been carried 

 out only ou a few trees and by the hand of the Eu- 

 ropean. It would on a la ge scale he very expensive, 

 no doubt, but incomparably less than that of Air.' 

 Kearney, as no selection is necessary, and therefore 

 no special ex minaticm of the leaves. Still I doubt 

 very much whether the process, as a remedial measure, 

 would prove "finaiicially practicable," to use Mr.' 

 Kcjirney's words. ^y. 



New Source of Sugar Production.— It seems that 

 the snccessful application nf the proce.eses for makinc 

 sugar trnm sorghum, discovered by Professors Scoville 

 and Weber, of the Illinois State Induslrial Univer- 

 sity, has caus.d great excitement all over the iftate. 

 Farmers are eagerly preparing to go into the sorghum 

 sugar businees, which »ill give them a larger profit 

 to the acre than any other product. On 250 acres 

 the Company who have heen using the new processes 

 have oroiiuce.l no less than 125,000 lb. of sugar and 

 22,500 gallons of molasses, valued at 19,000 dollars, 

 or an average of 76 d(dlar.i to the a.cre. — Public 

 Opinion, 



