Vol. XVI. No. 403. 



THE AGRICULTURAL NEWS. 



319 



THE BIOLOGICAL FACTORS AFFECTING 



COTTON PRODUCTION IN 



ST. VINCENT. 



The principal contents of the West Indian Bulletin, 

 "Vol. XVI, No. 3. just issued by the Commissioner of Agri- 

 culture, contist of three interrelated papers which have 

 reference to cotton growing in the West Indies. Summaries 

 of Mr. W. Nowell's paper on the internal disease of cotton 

 bolls, and that of Mr. W. N Sands on the cotton stainer, will 

 be found on pa^es 318 and 308 respective y, of this issue. 

 Mr. Harland's paper, based on the m-inurial experimenls with 

 cotton at the St. Vincent Experiment Station, e.xtends to 

 a detailed presentment and discussion of observations made 

 during the past season on the factors affecting the yield 



The results of the manurial experiments proper arc; — 



(1) That all the manurial plots show »n increased yield, 

 ■which in the case of the phosphorus potassiumcotton-seed 

 meal plots in the year under review amounted to 116 per cent. 



(2) That the element most needed in the plots is 

 potissinm, applicition of which gave an increase of 76 

 per cent. Shortage of potash showed clear effects on the 

 plants ill several plots by leading to the production of 

 reddish-coloured leaves with a tendency to drop prematurely. 



(3) Phosphate and potash was less beneficial than potash 

 alone. 



(4) Artificials and cotton-seed meal proved belter than 

 either alone. 



(.5) Cotton-seed meal alone at the rate of -500 Bb. to the 

 acie has been shown to be insufficient to meet the full require- 

 ments of the plants when grown on the same land for 

 a number of years. 



Perhaps the most important conclusion reached, which 

 was rendered possibh by the detailed nature of the studies, 

 is that differences in manurial treatment do not cause any 

 notable differences in the percentage of flowers producing 

 ripe bolls. 



The second and principal section of the paper is con- 

 cerned with the biological factors, apart from manuring, 

 which affect the yield, and is of great interest and importance. 

 The number of Howers opening daily in each plot of the 

 manurial series was recorded, and the production of bolls 

 was similarly observed. From these data a graphic repre- 

 sentation (Plate 1) of the flowering and boiling curves of the 

 plots has been constructed, which affords a definite picture of 

 the process of events during the course of the season. 



The first flowering curve (October-November) is followed 

 at an interval of some fifty d*ys by the corresponding boiling 

 curve of the first picking, and the contrast between the areas 

 enclosed by the two curves illustrates in a striking manner 

 the very great difference commonly experienced in St. Vincent 

 between potential and actual yield. The second flowering 

 curve (December-January) which is of considerable dimen- 

 sions, represents a capacity for production on the part 

 of the plants which is totally lost, for the reason that 

 infestation with internal boll disease becomes complete 

 during -January, and makes the keeping of the plants beyond 

 that month quite useless. 



For the purpose of detailed analysis of the losses occur- 

 ring during the effective part of the growing season a daily 

 examination of some thirty plants was made, and, as far as 

 possible, an accurate record was kept of the fate of every bud, 

 flower, and boll produced. The record of one plant is 

 reproduced in full (Plate 2), and the records of seventeen 

 plants, including for comparison Upland and hybrid types, 

 are given in abbreviated form (Plates 3-6). Only about 20 



per cent, of the flowers matured into bolls. The principit 

 cause of loss of crop in the effective period is the shedding 

 of buds and bolls. Heavy sledding took place in the latter 

 part of October and throug.hout November, of which the 

 shedding of buds and young bolls is attributed to the physical 

 effects oi the heavy rains which fell during that period. Very 

 considerable losses of older bolls occurred from shedding 

 induced by the presence in the boll of the .external (bacterial) 

 boll disease, and of the internal boll disease. Of these three 

 factors leading to shedding, and responsible for the serious 

 reduction of the first picking, the first two are dependent on 

 wet weather, while the third, internal boll disease, depends 

 mainly on the prevalence of the cotton stainer bug. The 

 weather tends to be drier towards the end of the year, but the 

 good effects which might be expected from this, and which could 

 be secured in increased measure by late planting, are nullified 

 by the increase in the number of stainers and the corre- 

 sponding prevalence of stainer-borne disease. The welfare 

 of the otton industry in St. Vincent thus deperid.s, in the 

 last resort, on the control of stainers. 



The study of the internal boll disease by Nowell, and 

 that of stainers by Sands, are thus closely related to the 

 general problem as revealed by Harland's observations, and 

 the three papers afford an example of that correlation of 

 ecological, pathological and entomological effort of which the 

 desirability is indicated in the editorial on another pa2e of 

 thi.s .Tournal 



From the analysis of the conditions in the various 

 i.slands made in th-! paper on internal boll disease, it will 

 be seen what widely different results are produced from 

 differences in the combinations of the factors concerni d, s > 

 that, to cake extreme examples, a matter which is vital for 

 St. Vincent has hardly any significance for St. Kitts. The 

 history of this investigation illustrates, moreover, the very 

 real value of the co-operation between the islands in the 

 collection and distribution of information which is secuici 

 by the existence of a central Department of Agriculture. 



THE SUGAR MARKET. 



The following information concerning the sugar 

 situation is abstracted from the latest report to hand of 

 Messrs. Gillespie Bros, and Co., dated New York 

 September 14: — 



The uncertainty regarding the future still tends to 

 check business, and while there are offers of Septem- 

 ber shipments at 5jc. per lb. c. & f., there was no 

 buying interest displayed here for the shipment positions. 

 Canadian refiners accepted a little business for fairly prompt 

 shipment at this figure, and we have buyers here for immediaie 

 shipment at the same price, but so far the lowest offers for 

 this position are at 6c. c. ct f. for basis 96° centrifugals. Porto 

 Piicos are ofi'ered at 6 OOo. per lb. with buyers at 6-77c., 

 the market being fairly steady around these levels The 

 chief matter of interest affecting this product is the advices 

 from Washington of the elimination of the consumption taxes 

 and clause repealing the drawback. 



Most of the refiners have been in session this week 

 with the Food Commissioner, and it was expected ia 

 some quarters that arrangements might be made whereby tha 

 balance of the present Cuban crop could be purcliased and 

 distributed among the several interests without competition 

 among themselves. 



All export businers is at a standstill owing to the 

 requests of the Government to di.-^continue all export .ship- 

 ments until sugar becomes more plentiful. 



