Report of the Work of The Rubber Research Board in 1947. The present report is the seventeenth Annual Report of the Rubber Research Scheme (Ceylon) as constituted under the Rubber Research Ordinance'(Chapter 302). CHAIRMAN'S REPORT Board Membership.—The following changes in the membership of the Board occurred during the year :— Mr. F. J. C. de Mel resigned and Mr. T. C. A. de Soysa was nominated in his place from 30th January. Mr. F. H. Griffith, M.P., left the Island on leave and Mr. J. D. Farquharson was nominated to act for him from 15th February. Mr. Griffith resumed membership on 22nd August. Mr. A. W. Harrison resigned and Mr. R. J, Hartley was nominated in his place from 14th March.* Mr. E. J. O. Richardson resigned and Col. J. T. Young was nominated in his place from 1st April. Mr. C. A. C.*Bowen left the Island on leave and Mr. A. D. Layton was nominated to act for him from 1st April. . Mr. Bowen resumed membership on 27th November. Mr^T. 'D' . Perera, C.C.S., Deputy Secretary to the Treasury, was nomi­ nated to represent the Minister of Finance in place of Mr. H. E. Peries, C.C.S., from 23rd October. JVfr. D. Rhind assumed duties as Chairman of the Board on appoint­ ment as Director of Agriculture from 20th October. Special mention was made of the valuable services rendered to ..the Board*by Mr. L. J. de S. Seneviratne who had served as Chairman from 14th February, 1944. The personnel of the Board at the end of 1947 was as follows :— • ; Ex-Officio Members :— The Director of Agriculture «— Mr. D. Rhind. Representing the Minister of Finance — The Deputy Secretary to the Treasury (Mr. T. D'. Perera, C.C.S.) Unofficial Members of Parliament nominated by H. E. the Governor ; The Hon'ble Mr. G. E. de Silva, M.P. " ' ; Mr. Simon Abeywickrema, M.P, • (Vacant). . # Members nominated by the Ceylon Estates Proprietary Association:— Mr. W. H. Attfield. . Col. J. T. Young. Members nominated by the Planters' Associa'ion of Ceylon :— Mr% F. H. Griffith, M.P. . Mr. K. C. L. Notley. Members nominated by the Rubber-Growers' Association :— Mr. C. A. C. Bowen. Mr. R. J. Hartley. Members nominated by the Low-Country Products Association of Ceylon :— Mr. W. Neal de Alwis, J.P. Mr. Noel de Silva. . Mr. A. M. Clement Dias. Mr. T. C. A. de Soysa. Members nominated by H. E. the Governor to represent smallholders :— Mr. W. P. H. Dias, J.P. • Mr. F. A. Obeyesekere. Meetings.—Meetings of the Board were held in Colombo on 8th April 12th May, 28th July, 3rd November and 15th December. Committees:— Experimental Committee — Mr. Thomas Amarasuriya acted for Mr. F H. Griffith during the latter's absence on leave and Mr. R. C. L. Notley acted as Chairman of the Committee during this period. The personnel of the Committee at the end of the year was as follows :— Mr. F. H. Griffith, M.P. (Chairman). Mr. W. P. H. Dias, J.P. Mr. Noel de Silva. • Mr. R. C. L. Notley. Mr. F. A. Obeyesekere. The Director (Convener). Meetings of the Committee were held on 8th April, 2nd May, 15th July and 2nd October. Smallholdings Committee.—There were no changes in the membership of the Committee which, at the end of the year, was a* follows :— Mr. W. P. H. Dias, J.P. Mr. F. A. Obeyesekere. The Smallholdings Propaganda Officer. , • The Director (Chairman and Convener). • A meeting of the Committee was held on 7th July. Members of the Board were also invited to attend this meeting and 9 members attended. Ad-boc Committees :— Finance Committee.—A Committee consisting of the Chairmaij of the Board, the Director and the Treasury representative was appointed to consider the financial position of the Scheme and formulate proposals for continuing the work of the Scheme, stating the minimum staff and funds required for the purpose. The Committee met on 25th November and submitted a report which was considered by the Board at its meeting of 15th December. Senior Staff Salaries Committee.—A Committee consisting of the Chair­ man, the Treasury representative and the Director was appointed to con­ sider the question of revising the salaries and war allowances of the senior staff; also re-organisation of the staff if necessary. The Committee met on 22nd April and 12th May and its report was considered by the Board at its meeting of 12th May, . Junior Staff Salaries Committee.—A Committee consisting of Messrs. \V. P. H. DiasT A. M. C. Dias, R. C. L. Notley and the Director was appointed to consider the salaries and terms of service of the junior staff. The Com­ mittee met on 15th April and its report was considered by the Board at its meeting of 12th May. . • London Advisory Committee for Rubber Research (Ceylon an,d Malaya). —The Board contributed jointly with the Rubber Research Institute, of Malaya to the cost of research on the quality and utilisation of raw rubber carried out at the Imperial Institute, London, under the control of the London Advisory Committee for Rubber Research (Ceylon and Malaya). Meetings of the Advisory Committee arid of the Technical Sub-Committee were held o o 7th February, 27th June and 7th November. Future Development.—Following the recommendations made by the Finance Committee, a deputation consisting of the Chairman, the Director, and five members of the Board, waited on the Minister of Agriculture and Lands with the request that the cess be increased to 50 cents per 100 lbs. Administration.—Dr. E. Rhodes assumed duties as Director on 26th February FINANCE. Income.—The Board's main income was derived from the cess on exports of rubber under Section 6(1) a of the Rubber Research Ordinance. The increased cess rate of. I cent per lb. became operative in January; thus the income from this source exceeded the estimate for the year. Monthly cess collections for the year were as fol lows:— B/forward Rs. 174,963.97 . January ... Rs. 21,515.56 July ... „ 38,024.27 February ... „ 35.837.68 August 49,308.64 . March ... „ 43,887.55 September ... „ 39,348.40 April 41,283.44 October 67,539.59 May ... „ 21.798.45 November .. . . ,, 38,962.96 June ... „ 10,641.29 December .., „ 43,001.57 C/over ... Rs!T747963T97 ~Rs. 451,149.40 A loss of Rs . '4 433.80 was incurred on the normal working of Darton­ field Estate and Rs. 2,622.22 on Nivitigalakele. Expenditure.—Current expenditure, exclusive of losses on estate working •acffounts, amounted to Rs. 435,895.68. The surplus of income over expenditure was therefore Rs. 31,754.62. Capital expenditure amounting to Rs. 118,450 was incurred mainly in respect of Agricultural Development Rs. 26,661 ; construction of Secretary-Accountant's bungalow, 1 junior staff bungalow, labourers' and attendants' cottages, and schoolmaster's quarters Rs. 66.155; alterations to experimental factory and laboratories Rs, 1,429; Hedigalla cart road Rs. 11,094; Furniture and equipment Rs. 6,186; Water and Power Supply Rs. 6,625; and Laboratory apparatus Rs. 300. Accounts.—The accounts for the year, with a Balance Sheet showing the property and liabilities of the Board, have been prepared and submitted to the Auditor-General for examination. Technical Reports.—The Director's report, which embodies the reports of the other officers, and the report of. the London Advisory Committee for Rubber Research (Ceylon and Malaya) are attached. (Sgd.) D. RHIND, March. 1948. • Chairman of the Board, Rubber Research Scheme .(Ceylon). 4 • DIRECTOR'S REPORT Th£ year has been one of uneasiness during which not only was it . not possible to enlarge the research staff in accordance with the Board's intentions, but the loss of experienced officers commenced. It has been possible to maintain the field experimental programme in spite of the absence of the Botanist on leave for four months. The advisory service and routine work on the chemical side has also continued, although in the absence of the Chemist during the second half of the year the longer range research work was necessarily in abeyance. The outlook for 1948 borders on the desperate as there is a strong likelihood that \he Director and the Botanist may be the only available research officers after the first quarter of the year. The. report includes a summary of the work of. each Department. STAFF. Director.—Dr. Edgar Rhodes assumed duty at the end of February. Chemical Department.—Oft the arrival of the Director, Mr. M. W. Philpott resumed full-time duty as Chenhst -until 6th June when he left the Island on long leave. Late in the year it was learnt with great regret that his services would no longer be available to the Scheme. Botanical-Mycological Department.—Mr. C. G. Hansford, Mycologist, was on duty throughout the year, but it became known during October that he intended to leave the Scheme's service. (He left Ceylon during January, 1948). Mr. C. A. de Silva Botanist, was on end of contract leave from lTlth September until the end of the year. (He returned to duty on 14th January, 1948). Soils Department.'—Dr. L . A. Whelan, Soils Chemist, was on duty throughout the year. Smallholdings Department.—Mr. W. 1. Pieris, Smallholdings Propa­ ganda Officer was on duty throughout the year and from 1st November he was assisted by Mr. H. H. Peiris who then assumed duty as Deputy Smallholdings Propaganda Officer. Estate Department.—Mr. G. P. N. de Silva resigned from the office of Estate Superintendent on 30th September and Mr. L. Wijeyegfoor^ewardene assumed duty as Assistant Estate Superintendent. The duties of Estate Superintendent proper were taken over by the Director. Headquarters Office.—Mr. C. D. de Fonseka, Secretary-Accountant, returned from overseas leave on 28th February and was on -duty during the remainder of. the year. Research Assistants.—These appointments were re-advertised during the year but no suitable men offered themselves. Personal enquiries and visits to the University have indicated that there is no likelihood of suitable men being available during 1948. C H E M I C A L D E P A R T M E N T Research W o r k . General.—The departure of Mr. Philpott on leave early in June and his subsequent resignation, coupled with the" loss of the key trained assistants* to more lucrative appointments, brought effective long range research to an end before the middla of the year and there is little, prospect of re­ commencement during 1948, • Control of Plasticity.—Further trials were made by Mr. Philpott to deter­ mine the effect of amines and nitro-compounds on plasticity and in these a slightly elevated temperature of 60°C was used. The dyes Bismarck Brown and Fuchsine which contain freeNH., groups cause progressive stiff­ ening. The m and p Phenylenediamines, which at room temperature induce stiffening behave *>mewhat differently at 60°C. and cause at first a pro­ gressive hardening followed by softening if the heating be prolonged. The o derivative accelerates the softening of rubber 60°C. Dinitrobenzene which produces a soft rubber at room temperature does not induce, progressively more softening in rubber heated at 60°C. Because the most active stiffening agents so far found are aromatic amines containing two or more nuclear N H a groups, it was thought that diphenols might also induce stiffening but both hydraquinone and resorcinol were found to be inactive. Of two tri- phenols tested, pyrogallol was inactive while phloroglucinol was strongly active. There is ample evidence to show that the stiffening capacity of diamines diminishes with increasing acidity of. the medium. Latex was coagulated with a range of acids of widely different dissociation constants and the order of increasing hardness of the rubber was the same as the order of decreasing dissociation constant of the coagulants used. It would appear from the above facts that softening by nitro-compounds and hardening by amines are probably connected processes and that soften­ ing by nitro-compounds may not be due to accelerated, oxidative breakdown. It would also appear that the diamines are active only in the non-ionised form. Mr. Philpott presented a paper on the control of plasticity to the 1947 International Congress of Pure and Applied Chemistry. Rubber Seed Oil. The prevailing world scarcity of vegetable oils and their high prices led to a re-consideration of the possibility of collection and marketing of rubber seeds. A circular was issued inviting estates to make experimental collections during the 1947 seed season with a view to determining the probable cost per ton under Ceylon estate conditions. At the same time two oil milling concerns agreed to make expression trials on a sufficiently large scale to determine the commercial possibility of. local expression of oil. The seed season in 1947 was however a complete failure because of the most severe attack of Phytophthora pod disease for many years, and it was .quite impossible therefore for reliable information on collection costs to be obiaifled. The two oil milling concerns did with some difficulty obtain sufficient seed for small scale trials which were in both cases disappointing particularly with regard to the percentage of free fatty acids which was undwly high indicating that in spite of the fact that the seeds' were heated immediately on receipt by the oil millers, enzyme activity had. been too great between seed fall and expression. These meagre results are sufficient to indicate however :— (i) that in Ceylon the total available amount of seed must always be expected to be very much less per acre than in Malaya where Oidium attack on the flowers and Phytophthora attack on the seed pods is almost negligible, by comparison. The 1947 seed season has indicated that the Ceylon crop can in bad seasons be reduced to negligible proportions; ' ( i i ) that if oil of. satisfactory commercial quality is to be obtained, lipolytic enzyme activity must be minimal which pre-supposes rapid collection and sterilisation of seed before extraction of oil commences The terrain in Ceylon is hilly, extensive use is made of ground 6 • covers and almost no estates have either the means of sterilisation, or are situated close to existing copra kilns which might be used for the purpose; seed may therefore lie for days before it is found • and be virtually useless even before it is sterilised. The fact that although the Ceylon oil millers were already aware of these, dangers %nd did their best to get their suppliers to avoM them, the quality of the oil obtained was sub-standard, gives rise, to very serious doubt as to whether oil from wholesale collection of seed from Ceylon estates could ever be of consistently good commercial quality. The collection of seed on smallholdings could in certain circum­ stances offer perhaps more possibilities than the collection from estates. Such holdings are more frequently on flatter ground which is usually bare. Seed could be collected daily by the smallholders' children during the July-August seed season, but an elaborate depot organisation would be necessary to which the seed could be taken for sale and from which seed could be transported d^aily to sterili­ sation centres. The Rubber Commissioner's present depots and transport system could meet these requirements but until rubber seed oil from other sources has established itself on the world's markets at a known price it would not be possible for the Rubber Commissioner to consider extending the services of his depots for these purposes and arranging for sterilisation and final sale. Spec ia l R u b b e r a n d V u l c a n i s e d P r o d u c t s On behalf of the Department of Commerce and Industries a consign­ ment of. captax softened rubber was prepared for trial by a tyre many iacturer in U. S. A. Although the manufacture of vulcanised articles no longer comes within the purview of the Scheme's activities, the manufacture of 1,000 seats and 1,000 pairs of arm rests in sponge rubber was undertaken and com­ pleted for the equipment of a cinema. No further work of this kind will be undertaken in the future. 0 Estate Manufacture. Since early June it has been necessary for the Director to takeover the day-to-day duties of advisory chemist. In the early part of the year there was a serious shortage of sodium bisulphite which gave rise to .many enquiries for substitute materials and for several months it was necessary for crepe producing estates to use radium sulphite in abnormally large amounts in order to preserve."a good colour. This naturally entailed the use of unusually large amounts of coagulant but until the supply position eased there was no alternative. In this connection and at this time Mr. Philpott made the interesting observation that if Captax (MBT) is added to latex in amounts equal to 1 part per 5^000-10,000 parts of rubber, discolouration" of the coagulum is suppressed. Estates have so far not been recommended to adopt this procedure. Two estates have erected creaming plants during the year and their rubber-makers have been trained in the manufacture and testing of creamed latex. Other estates have made preliminary trials. In all cases all possible advice has been given. • Meteorological Observations The weather summary for 1947 obtained for the Colombo Observatory Rainfall (ins.) Highest monthly rainfall (ins.) Highest daily rainfall (ins.) Highest shade-temperature (day) Lowest temperature (night) Number of rainy days is shown below and is based on data 1947 172.98 26.39 (October) 6.20 (20-21.10.47) 94-4°F (28.2.47) 62 5°F (10.2.47) 225 1946 158.0 * 24.7 (Dec.) 7 4 9 (28.4.46) 94.2°F(l 1.3,46) 63.8°F (5.1.46) 244 B O T A N I C A L A N D M Y C O L O G I C A L C. G. Hansford. C. A. de Silva.- D E P A R T M E N T Mycological. The 1947 season in the low-country showed on the whole a rather mild attack of Oidium, though late wintering trees suffered at least one complete defoliation. The wintering seasori was delayed, owing to the heavy rainfall of the previous November and December, and the first signs of wintering on Dartonfield occurred in the first week of. January, whereas the present wintering season has begun in early December. By the end of* January, 1947 the first trees had commenced refoliation and on the 7th February, a few colonies of Oidium were found scattered at random over their leaves which had then reached the full green stage and were practically of mature size; the colonies were confined to the upper surfaces of the few leaves infected and in most instances only a single colony was present on a leaf. These leaves did not shed, but the Oidium remained on them producing abundant conidia for 3-4 weeks. During the remainder of February the fungus gradually became more prevalent, though mostly confined to leaves in the green stage of semi maturity and hence very little leaf shedding occurred. About 1st March the habit of the fungus suddenly changed and wholesale infection of bronze leaves occurred during the following week, with consequent severe leaf shedding during the next few days. These conditions continued for the remainder of March, after which the epidemic gradually died down except on the extremely late winter­ ing clone PB. 6/9. Fortunately during the 1947 refoliation season the bulk of the trees on most estates had passed the susceptible stage before the period of severe infection occurred, and hence the epidemic as a whole was less severe than on many occasions in the past. The story of the 1947-48 wintering period cannot yet be written, but conditions are now almost the exact opposite of. those prevailing last year. Instead of a record rainfall in November-December, we have experienced virtually a record drought, with the result that wintering of the rubber trees has been acwanced about six weeks for most clones. Yet the story so far of the annual Oidium attack has been identical with that of the last season. The very first tree to re-foliate has shown a few scattered colonies (six in a l l ) -on its fully expanded green leaves, limited to their upper surface; these were discovered on December 16 and ccftifirmed on December 18th. 8" • No trace could then be found on neighbouring trees with somewhat younger leaves but until the end of the month there was a gradual spread of the fungus on to them, limited almost entirely to the upper surface of, the leaves. Thus in the low-country of Ceylon the Oidium epidemic commences each yea* a#s a few colonies on the very early wintering, trees and spreads from them "for about a month to the fairly mature green leaves of their successors to winter. Eventually the foliage of the latter becomes quite heavily attacked, but being past the extremely susceptible bronze stage it does not shed in any serious amount. Then for some reason still entirely unknown the fungus suddenly makes a large scale attack on younger bronze leaves, develops very rapid.ly on them and causes wholesale shedd­ ing within 5-6 days after infection. Some years this severe attask may be repeated once or twice before the epidemic gradually dies down and the trees are able to form a permanent foliage for the year. In other years most trees suffer none or only a single defoliation. From this general picture of the Oidium epidemic in the Ceylon low-country arise a number of questions, and attempts have been made during 1947 to provide answers to some of them. The first question is that of the persistence of Oidium in the low-country throughout the year. At Dartonfield there is a small area of a very late-wintering clone PB. 6/9, and in 1947 it suffered defoliation, from Oid&um repeatedly until mid-May, and it was not until towards the end cf June that it was able "to form a reasonably dense canopy. Even then some of its leaves bore active Oidium colonies up to early August. Unfortu­ nately this year a severe epidemic of Phytophthora occurred in July-August so that normal conditions of. foliage renewal were considerably upset. In September, after the leaf fall caused by this fungus there was an abnormal amount of young foliage present on the trees, and it was expected that Oidium would attack it. Close examination of many trees failed to reveal any sign of its presence, however, although a few colonies of Oidium had been found towards the end of July on a tree artificially defoliated on July 1st. This absence of Oidium on young foliage in September was very unexpected, especially as on October 1st two colonies were found on a 2-year-old seedling tree growing in a water-course reser^t ion at Darton­ field. It is still possible that occasional colonies may have occurred on the September crop of new foliage, and were missed by the field glass exami­ nations made. The Mycologist's opinion is that this possibility pi very small scale existence of Oidium throughout the year in the low-country rubber plantations cannot be entirely ruled out, and would account for the few colonies appearing on the very early wintering trees each season. The second point arising from the field study of the annual Oidium epidemic is the origin of the original colonies found each season. The old explanation was that the fungus was able to exist in some resting form in the buds of the trees, as is known to happen in the case, of some nearly related mildews of temperate plants. Mere examination of the occurrence of the original colonies of the rubber mildew shows that there is no definite relation to buds. The colonies are few in number and may occur on single leaflets of the comparatively large number formed from one dormant bud ; they are most often situated in the centre of the upper surface and never occur on the lower surface; and finally bear no relation to the .stem of the twig on which they occur. It is concluded that they result from sporadic air-borne comdia of the fungus. This conclusion was tested by enclosing dormant*branches in cellophane bags, and allowing the buds to develop their foliage within the bags while protected from Outside infection. Great trouble was found in rendering these cellophane bags capable of standing up to heavy rainstorms, but the trials were successful enough to indicate that no Oidium develops under such conditions. E v e n l n the case of bags damaged, such infection as did occur was always on leaves exposed to the outer»air through openings in the bags. It is possible However that the conditions of absolute saturation of moisture inside the bags would prevent development of Oidium, and this alternative explanation of the experimental results needs testing further. All that can now be said is that evidence hitherto indicates that) the fungus is air-borne to the leaves of the trees first to winter in each season, and that having once infected these, the origin of the epidemic is thereby accounted for. With regard to clonal resistance and susceptibility, we have as yet no evidence of any sufficiently high degree of resistance to be of commercial value amongst any clones at present in existence in Ceylon. One of the more promising kinds of resistance was shown in 1947 by HC. 28 — a late wintering clone which becomes quite heavily infected with Oidium but shows comparatively little leaf, shedding. Further observations are needed on this matter, especially in view of the marked differences in behaviour shown by any individual clone when planted in different situations. This variability in reaction in Oidium also extends to the relative date of winter­ ing of any clone in comparison with others close by, and is also shown from season to season. For instance in the 1946-47 season the first trees to winter and' to refoliate at Dartonfield were those of R.R.I. 506, and the first signs of Oidium were found on one tree of this clone. In the 1947-48 season some trees of PB. 183 which had not recovered at all well from tlje Phytophthora leaf-fall in August-September, were first to winter, and one tree of this clone showed the first colonies of Oidiuwi this season. The conditions governing the sudden increase in severity of Oidium attack on young bronze leaves each year remain entirely undiscovered. Much time has been spent by the Mycologist in detailed examination of meteorological records dating back to 1935, and no correlation has yet been discovered to indicate that one or two meteorological factors control sucii development. Oar present knowledge renders it impossible to give more than 4 or 5 days' warning, of an impending epidemic, and such a warning would be of use only on the individual estate under very detailed day to day observation^ Hence it is not yet possible to give estates in general any useful forecast of when to commence dusting operations, or whether these can be dispensed with in any given season. If it became possible even to give 14 days' notice of danger of heavy attack then in years of light attack estates might be saved this expense. Present prospects are that such a long-term forecast will not become possible for some years to come. The condition and yield figures of neighbouring estates may be taken as reflecting a general summary of conditions over the past 10 years, and in this matter a comparison between Dartonfield, dusted regularly each year, and Mukalana never dusted, shows that Oidium in this district has not been severe in its effects. . . Conditions relating to Oidium on estates in the drier and more elevated districts of Matale and Kandy are altogether different from those in the low-country. The fungus exists in quantity throughout the year there on all trees having foliage in a susceptible condition. In these districts it is virtually impossible to obtain a reasonable density of, foliage without the most careful and regular sulphur dusting* possible. Before leaving the subject of the epidemiology of Oidium it is neces­ sary to correct a statement often repeated in the past, that the fungus is •capable of infecting mature rubber leaves. No single case of such infection has* been observed by the Mycologist, and all spots and. deformations shown by mature rubber leaves as due to Oidium attack are merely the long- term resTilte of infections occurring at the latest about*>3 weeks after the buds open. After infection has once occurred the fungus is able to exist on the leaf in active and sporulating condition for 6-8 weeks at the most, when its mycelium gradually disintegrates and dies away. The only reason­ ably efficient control measure for a disease of this nature, affecting a com­ paratively large tree is that of sulphur dusting both to protect young foliage against infection and to control to some extent the development and sporu- lation of colonies already formed. There is some indication ttfat present apparatus and sulphur dusts are not ideal, but with the limited facilities available to the Rubber Research Scheme it is not possible, to make detailed investigations of these matters. Fortunately Imperial Chemical Industries have recently taken an interest and have promised to make trials of new dusts and machines in England, before sending them to us for field tests. From their resources we may hope to obtain results.of practical value to rubber planters in a much shorter time than would otherwise be possible. The essential of control of Oidium in a district liable to severe and regular annual attack is very careful supervision and frequent repetition of small doses. Unfortunately the districts concerned are those in which the crop is least profitable, and hence the recent Rubber Commission has recommended that rubber is no longer a practicable crop there. The rubber estates of the low-country districts of Ceylon suffered an exceptionally severe epidemic of Phytophthora leaf-fall in August-September 1947, probably the worst outbreak for about twenty years. Reports and inspections showed that no individual clone possessed everywhere any marked resistance td the attack, though a few clones such as BD. 5 proved particularly. susceptible on almost all estates. The other standard clones such as TJ. 1 and PB. 86 on most estates showed moderate attack, but somewhere or other each clone suffered severely. Following the actual leaf fall due to the attack outbreaks of various forms ^ f bark rot and canker on branches and main stems occurred, though in the case of these forms of Phytophthora attack the standard clones TJ. 1, PB. 86, HC. 28 and GL. 1 did not suffer to the same extent as some others including BD. 5 and PB. 183. All low-country estates were advised of tlie "dangers consequent upon this severe attack of Phytophthora and special precautions must be continued at least until the end of. 1948 to ensure that all canker and bark rot patches are thoroughly cleaned up and healed. With*.the present economic situation of the Ceylon rubber industry, it is manifestly completely impossible to attempt to prevent Phytophthora leaf-fall,.but it is important to clean up annually all patches of stem and branch attack of this fungus. The question of root disease, almost entirely due to Fomes lignosus, in replanted areas is coming very much to the fore in view of the heavy replanting programmes now under way. There appears to be much more danger of damage from this disease in replanted areas than in rubber planted on virgin land, probably due entirely to the presence of the susceptible roots of the old rubber in the soil. - Present experience leads to the view that in many fields of old rubber in Ceylon there exist frequent incipient or quiescent foci of Fomes root disease, though the old trees do not show any symptoms. When the rubber is felled and replanted, the first sign of ii the presence of Forties is the death of a proportion of the young plants usually about 9-12 months after planting. Their roots show the typical mycelial strands of the fungus, which cannot be mistaken. Although it may not prove possible completely to prevent such attack in young replanted fields, there are a few precautions which can be adopted to minimise the danger. At the time of felling the old rubber, the main roots e^pcsed by felling should be examined immediately for signs of" Fomes; a few hours' delay may obscure all signs. Infected or doubtful trees should be marked and later their root systems further exposed for detailed examination. Where the fungus is found, all infected roots should be carefully dug up and burnt, as completely as possible, before replanting is commenced. Where the old stand has been poisoned with arsenite, this precaution is not possible* The bases of the old trees after felling are best left in situ.. as we have found at Dartonfield that they form useful indicators of Fomes. If they have been attacked by this fungus, its fructifications soon appear on the rotting wood, instead of the normal crop of other harmless wood rotting fungi, and then all roots belonging to the infected stump and-its immediate neighbours of the old stand should be opened up and infected material burnt. If the Fomes patches are not so treated immediately they are noticed there is danger that the mycelium may spread rather extensively along the dying root systems of. the old stand, and hence infect a much larger area than would otherwise be the case. The disease is capable of causing considerable damage in young replanted fields, especially now that cur modern fields contain a much closer stand of plants, and it should prove well worthwhile to take steps to control it at the earliest possible stage, before the infection has become widespread and expensive to treat properly. Planting Material. Studies of Clones and Seedling Families.—3,046 trees were test-tapped at Nivitigalakele and Dartonfield consisting of local and foreign clones and clonal seedlings. The more important results are detailed under :— Prang Besar Isolated Gardens and Tjikadoe Seed.—This seed was imported from Malaya and the Netherlands East Indies and planted in two clearings in 1932 and 1935. The trees have been test-tapped on S/2, d /2 , 100% system fratn 8 to 10 years up to October, 1947 when both areas were put under general commercial tapping. The test-tapping yields for the final year are given in Table I together with the yields of 3-tree PBS clones from, selected mother trees of Plot C Prang Besar seedlings. The Tj ikadoe seedlings selected on vigour of growth have done better than those selected on test-pricking. The yields of the PBS. clones are very promising and 6 of these clones which have been planted in a large sca le - clone trial have given an average of 15 lbs. per tree per year of 130 tappings for 1947-48 in the seventh tapping year. Incidentally these buddings which are planted in a more favourable area of the 1935 clearing have grown better than most of the seedlings. The incidence of. Brown Bast disease has been quite marked in the seedlings and in general it is found that seedlings are as susceptible to the disease as buddings. New Trials.—A large scale trial for comparing clonal seed against budd­ ings was completed at D'artonfield. 3 families of illegitimate seedlings of clones TJ. 1, PB. 86 and PB. 5/139 and a collection of hand pollinated seedling, families representing a hypothetical seed garden were included for trial with clone TJ. 1 as the budded material. 36 tree plots were used for each of the 5 selections of planting material replicated 8 times, the area being planted at a density of 256 trees per acre. Thinning out will be carried out when the plants are 12 irfches in girth on vigour of T A B L E I Material Planted • as stumps Year of tapping No. of . trees tapped Mean yield in lbs. pe% tapping year per tree Mean girth in ins. 1947 Brown Bast cases Tjikadoe Isolated Garden Seedlings selected by test- pricking 1932 10 154 5 9 • 44 Tjikadoe Isolated Garden Seedlings selected for vigo­ rous growth L 1935 9 103 9 0 3 9 0 47 Prang Besar I. G. Seedlings, Plot B 1935 8 123 9-9 3 4 6 48 Prang Besar I. G. Seedlings, Plot C 1935 8 56 6 3 3 2 5 7 PBS clones, Plot C 1935 7 54 1 3 0 361 6 . growth, yield- and secondary characters and permanent tapping will co- mence on the selected trees at a density of 1 6 0 trees per acre. The experi­ ment should give valuable information on the potentialities of clonal seed compared with the best yielding clone TJ. 1 under the conditions laid down for the planting of clonal seed. a Hand-pollinated seed from the 1 9 4 4 and 1 9 4 5 seasons totalling about 5 , 0 0 0 seedlings and 1 , 3 5 5 derived clones in 5 tree plots were p l a n t e d at t h e Hedigalla sub-station and on 9 outside estates during the»ye£r under review. N o . 3 R e p l a n t i n g E x p e r i m e n t , Dar tonf ie ld 1936.—The experiment pro­ vides for a comparison between 3 methods of establishing budgrafts fh the field. Girth measurements were taken in June 1 9 4 6 and 1 9 4 7 . The figures are summarised in Table II together with the yields for 1 9 4 7 . The slumped buddings were first tapped in March, 1 9 4 2 , the budded stumps in December, 1 9 4 2 and the field buddings in December, 1 9 4 3 . The excess of yields of both stumped buddings and budded stumps over field buddings still persists in. the 5 t h year of tapping. • The Botanical Department supervised the commercial tapping in this area for the second six months of 1 9 4 7 to study the relationship in yield records taken from one sample tapping per month and yields obtained from the general estate from commercial tapping. The yield per tree per tapping in grams of d r y rubber from test-tapping and commercial tapping were 2 4 . 1 and 2 1 . 2 , respectively. • 13 • Material Age June 1947 in years Mean Girth in Inches Yield* pjsr tree • per 1946 1947 Increase 1946/47 tapping in gms. 1947 Stumped ljuddings Budded stumps Budded in field 11 11 lOf 2829 27 33 - 24-21 2974 29-22 26T3 1-45 1-89 1-92 24 5 23-2 175 . Sign, difff (.01) 1 44 1-47 This preliminary investigation shows that the method, of test" tapping i9 a reliable guide if allowance is made for the fact that test-tapping is carried out on normal tapping days only, while the estate shows records of tapping under all conditions of weather. The investigation is being continued. S t o c k E x p e r i m e n t , Dar tonf ie ld 1941.—In this experiment 5 clones of "R.R.I. 5 0 0 Series" were budded on 5 illegitimate seedling family stocks and on unselected seedlings. The budgrafts were planted in June 1 9 4 1 . Each monoclonal block was made up of 1 6 sub-blocks each sub-block consisting of 6 single budded tree plots of the various stocks replicated sixteenfold. Unbudded seedlings of the various stocks were planted in 6 tree sub-plots replicated sixteenfold as in the budded areas. Girth measurements were taken in May and a summary of. results is given in Table III. As in previous years the differential effect of stocks on growth of scion is not of any practical importance. The best growth of unbudded s e e d i n g stocks is to be found in the AV. 1 6 3 family. T A B L E III • _ Mean Girth in Inches Stock Un­ Sign, diff Family TJ. 1 AV. 163 B D . 10 BS. 3 MK. 1/1 selected - (-01) ScifTh growth Unbudded 16.5 17.3 16.6 17.0 169 16:9 'Not sign. - Seedling 19.0 2.4 Families 20.3 22-2 20.5 19.8 19.8 Stem a n d B r a n c h B u d d i n g E x p e r i m e n t — Hed iga l l a 1944.—This experi­ ment was designed to test the differences in performance of buds taken from different parts of the same parent plant classified into 'stem' and •branch' buddings. Budded plants established from the various types of buds were planted in a split-plot design using 1 0 clones, 3 types of budwood with 5 replications. The analyses of the girth measurements after 3 years" growth showed no significant differences between the various types of buds used, • . I T A B L E II 14 a N e w C l o n e s f rom T j i k a d o e Seed l ings and Esta te M o t h e r Trees .—Fie ld N o . 6A , 1939 Clear ing , Nivit igalakele.—44 clones planted in this area are made up of clones established from high yielding Tjikadoe seedlings, estate mother trees, marcots and controls of the better known local and foreign clones planted on a large scale. The la3'out consists o f ^ O polyclone blocks of 44 single tree plots representing the 44 clones. Tapping commenced in 1946 and the mean yields based on two sample tappings per month of the more promising clones compared with controls are given in.Table IV, T A B L E IV Yield of New Clones, Field 6A, 1939 Clearing, Nivitigalakele. Tapping System S/2, d/2, 100%, 2 Sample Tappings per Month Clones No. of trees tapped No. of cases B.B. Yield per ann 1945/46 in lbs. pe urn. 140 t 1946/47 r tree appings 1947/48 Mean girth in inches Sept. 1947 *NAB. 17 12-19-20 5 1 7 9 12-2 25-1 *NAB. 16 8T8-20 — 5 1 6-6 9-4 22-7 • N A B . 15 920-20 — 4-4 6-8 1 1 6 2 6 0 *RR. 19 2-16-18 1 4-3 4-5 5 3 2 2 1 . R R . 15 7-17-18 — 3-8 4-5 5-7 21-9 *NAB. 20 11-20-20 — 3 4 6 3 10-2 25-8 NAB. 21 6-19-14 5 2-9 4-3 6-4 23-4 f N A B . 12 9-19-18 — 3 0 5 0 8-5 25-3 fNAB. 8 8-18-18 — 2-9 4 5 7-9 . 251 NAB. 3 5-18-17 3 2-9 4 1 . 6 0 21-5 NAB. 11 11-20-20 — 2-7 4-8 0 7-2 24-5 NAB. 1 1020-20 — 2-3 4 0 5-9 26-7 NAB. 19 10-20-19 1 2-2 3-5 5-3 29-9 NAB. 4 8-20-20 — 2 1 3-7 5-3 .25-2 NAB. 5 8-19-19 — 2 0 3-8 . 5-4* • 241 NAB. 22 10-20-20 — 1-9 3 4 6 0 27-8 NAB. 2 10-18-19 — 1-9 3-7 5 3 271 NAB. 18 10-19-19 — 1-5 3 1 5-3 2 i ;2 Controls • TJ. 1 7-17-19 1 2-6 4-7 5 9 23-3 PB. 86 9-20-20 — 3-9 6 1 8 4 21 5 GL. 1 2-19-20 —• 4-0' 4-8 7 0 21-7 MK. 3/2 • 11-20-18 2 2 1 4 0 5-7 24-9 Significant difference (•05) 1-2 1 5 * Clones sleeted for large-scale trial. \^to be]included later. NOTE—Under the heading ' m No. of trees tapped " the figures indicate the number of trees tapped each.year. 15 together with figures for growth and incidence of disease. 4 NAB. clones Nos. 15, 16, 17, 20 and RR. 19 have been selected for a large scale clone trial in 1950. It will be noted that the control clones under polyclcjne TABLE V o • Trial of Foreign Clone?, Field 6B, 1940 Clearing, Nivitigalakele. Tapping System S/2, d/2, 100% Yield in lbs. per tree per Mean girth • Clone No. of trees annum, in inches, tapped 140 tappings 1947 January '48 • NAB. 26 24 6-4 22-6 RRIM. 511 21—23 5 9 2 0 6 PB. 6/50 23 5 9 24 9 RRIM. 513 22—24 5 8 2 0 2 RRIM. 500 19—21 5 6 2 1 2 AV. 255 24 5-6 24-1 RRIM. 501 20—22 5 4 19-5 RRIM. 504 19—22 5 1 201 GL. 1 13—17 51 19.7 RRIM. 506 19—20 5 1 2 0 2 RRIM. 514 14—23 4-9 18-7 PR. 107 22 4-7 2 1 2 PR. 106 21—22 4 5 211 RRIM. 519 17—21 4 5 19 5 PB. 5/57 '20—22 4-4 211 HC. 28 23 43 25 0 Waringiana 4 23 4-2 21-7 PR. 105 ,» 16—22 4-2 199 B D . 17 20—21 4-1 199 B. 6 21—23 4 0 21 2 B. 7 . 14—20 4 0 198 NAB. € 4 * 22—23 4 0 21-5 B. / 24 3 9 2 3 3 WG. 6278 22 3-9 20o TJ.* 1 22—23 38 226 Lunderston N 22 3 8 2 0 7 Pilmo»r B. 84 23 3 5 21-4 Kali Djeroek 1 20—21 3 5 20 3 B. 13 24 3 3 2 1 9 B. 3 12—18 3-2 1 9 3 RRIM. 518 19—21 3 1 1 9 2 Parawatte 1 15—19 3 0 197 • MK. 1/3 18—22 2-8 21-5 NAB. 25 22 2-8 2 2 0 AV. 352 23 2-6 2 2 5 Pilmoor D. 65 11—18 2-4 187 w NOTE—Control clones are italicised, 16 conditions are not up to the standard of growth of some of the new clones. The yield of clone PB. 86 is reassuring. • Tr ia l o f F o r e i g n C lones , Fie ld OB, .1.5)4.0 Clear ing , i \ iv i t iga lake le .—The experiment was primarily intended to test foreign clones of promise under local conditions. A few local clones and controls wene included to make ** 'tip a total of 36 clones. The experimental layout is a quasifactorial- lattice design adopted with 2 replications of 3 arrangements each. Plots consist of 4 trees and total number of trees tested is 24. The trees were taken into tapping in 1947. The yield figures have not been analysed statistically as the full number of trees in the various clones have not come into tapping. Yield and growth figures are summarised in Table V. It would be premature to comment strictly on these early yields bu* there are indications of good results from a number of clones on trial in this area, under the conditions of the experiment. T a p p i n g E x p e r i m e n t s . • Ma tu re Seed l ing R u b b e r , Dai'tonfield 1937.—The 10th and final year of this experiment was completed in February, 1947. The yields for the year 1946-47 and for the 10 year period were summarised in the Combined 1st and 2nd Quarterly Circulars for 1947. The double-three system gave an increased yield of 19 per cent over the control up to the 7th year. In the 8th, 9th and 10th years there were signs of an apparent deterioration in yield. This was attributed to the tapping of somewhat immature bark, resulting from the high consumption of bark on this -system on old seedling trees. The dry rubber content figures up to the end of the 10th year were quite satisfactory. Compared with the double-four system the cost of tapping on double-three was 15 per cent higher based on yi*ld and tapping task, other conditions being equal. T a p p i n g E x p e r i m e n t N o . 14 ( L a d d e r T a p p i n g ) Dar tonf ie ld 1944.— This experiment was started on old seedling rubber in August 1944. The double-three system is compared with (a) double-three plus a half circum­ ference V cut at 8 feet from ground level tapped downwards with the aid of a ladder and (b) double-three plus half V cut opened on virgin bark and tapped upwards. In March, 1946 the tapping system was changed from double-three to double-four and the comparisons were carried on as before. A summary of the yields as a percentage of the control 2S'2, d'3, 133% or 2S/2, d/4, 100% are given in Table VI. . • T A B L E VI Period S /2+V/2 (Ladder) d/3, 200%* S/2, V/2 (Upward) d/3, 200%* . «*.. Sign, diff. % (•01) Lower cuts Upper cuts Total Lower cuts Upper cuts Total Aug. 1944 to July 1945 87 56 143 '80 56 136 174 Aug. 1945 to July 1946 87 60 147 73 55 128 28-8 Aug. 1946 to July 1947 86 63 149 77 51 128 22-5 * Changed Match, 1946 to d/4, 150% TABLE VII. Tapping Experiment No. 5, Budded Rubber Mean yiekl in pounds dry rubber per tree per annum and as per cent of S/2, d/2, 100% Clone Original Tapping System i • • 1941-42 1942-43 s 1943-44 1944-45 1945-46 • . 1946-47 NewB.B. cases 1946 to - 1947 Total cases 1942- 1947 • No. of trees wind- damaged GL. 1 S/2, d/2, 100% S/3, d/2, 67% S/2, d/3, 67% 2S/2, d/4, 100% 5.47 100% 4.44 81% 4.07 74% 5.07 93% 6.57 100% 5.37 82% 6.02 92% 6.30 96% 8.26 100% 6.84 83% 8.33 101% 10.18 123% 4.28* 9.29 5.80 5.14*» 10.08 9.57 12.31 5.22 9.45 8.90 9.90 5.49 5 2 45 29 25 30 • 1 * A V . 256 • , Buildings and roads .., 16 3 08 Scrub, etc. ... 2 2 19 Newly acquired land . ... 2 1 22 Total ... 179 0 19 Rainfall.—172.98 inches. Rainfall was above average. The South-West* Monsoon rains burst unusually late in June and the August rainfall was the highest recorded for j o m e years. A monthly summary is given on next pagja. . There was a further increase in the yield of the demonstration replanted block at Baddegama (clone PB. 86), the average for the year being approxi­ mately 34 gms. per tree per tapping. 76 trees are being tapped. The block was planted, with budded stumps in November 1938 and is in tapping since September, 1943. The 5 other demonstration blocks in the ranges were m°air»tained in good order but further interest in the block at Ratmal- goda (Horana Range) was abandoned owing to complications that arose over a dispute in ownership, which made proper tapping and maintenance impossible. Demonstrations In addition to the demonstrations mentioned elsewhere, 39 budding, 266 tapping, 194 disease treatment and 220 miscellaneous demonstrations were conducted by Instructors. Nurseries 10 demonstration nurseries were opened in the ranges for giving budd­ ing demonstrations and supplying small quantities of budded stumps to smallholders. Other nurseries opened in previous years were maintained and budded. 1538 nursery plants were budded by Instructors and 320 budded stumps sold. 146 yards of budwood were issued for budding nursenes. 5 private nurseries were opened by smallholders with the Instructors' advice. Compost Pits. The simple process of collecting green loppings in a shallow pit and turning the heap at 10-14 days' intervals for making compost was popular­ ised by the opening of demonstration compost pits in each range. A total of 47 demonstration and 26 privately-owned pits were opened. The compost made was given free to Smallholders or used for manuring demonstration nurseries, replanted blocks, etc. 25 1946 1947 5 years' average January 1.66 ins. 12.45 ins. 7.15 ins. February 7.84 „ 602 „ 6.54 „ March • 9.93 , 15.40 „ . 12.26 „ April 20.25 „ 7.16 „ 12.20 „ May 7.46 „ 13.92 „ 22.66 „ June 13.48 „ 25.04 „ 19.24 „ July 8.59 ,. 12.27 „ 8.79 „ August 14.79 „ 24.04 „ 12.72 „ September 11.62 „ 12.86 „ 13.54 ,, October 20.65 „ 26.39 „ 25.07 „ November 17.04 „ 8.65 „ 16.88 „ December 24.67 „ " 8.78 „ 12.98 ,, Total 157.98 ins. 172.98 ins. 170.03 ins. Crop.—The crop for the year was 67,875 lbs. which is 92.68 per cent of the estimated crop and 125 lbs. above that of. 1946. The loss in crop is attributed partly to the replanting of 11 acres which was intensively tapped the previous year and partly to weather which was unfavourable to crop. Yield records for individual fields are as follows:— - Field No. Date of planting Total crop lbs. Acreage tapped Yield per acre lbs. 1 1910 12,179 28J 427.3 % 1913 605 1 605.0 3 1917 10,744 - 24 447.6 4 1911 534 H 427.2 5 1913 20,364 46£ 437.9 . * 6 1934 " 6,149 n 793.4 7 1938 9,796 16* 602.8 8 1936 6,424 9* 676.2 9 1939 773 l i 618.4 10 1938 307 •6* 47.2 67,875 142* 476.3 Tapping.—The commercial areas were tapped on the 2S/2, d/4 system. Bark consumption 3* inches on each cut. Upward cuts were opened on otherwise worthless trees. Tapping was discontinued on 21st February and resumed on 17th March. Tapping of the experimental areas was under the supervision of the Estate Superintendent. The Visiting Agent reported favourably on the standard of tapping in general. The average daily intake per tapper was 6.5 lbs. compared with 6.6 lbs. in 1946. Average daily pay amounted to Rs. 1.46 including dearness allow­ ance for tappers. 26 Total ... 82 0 Manufacture.—Some sole, crepe was manufactured, after the middle of May. A summary of grades prepared during the year is given below :— • Grade . lbs. Per cent Total Smoked Sheet No. 1 785 1.14 „ 1.14 Sole Crepe „ 1 5,471 8.07 8.07 Latex Crepe ,, 1 28,239 41.61") do „ 2 10,567 * 15.57 y 73.02 do „ 3 10,753 15.84 J Scrap Crepe ,, 1 6,056 8.925 do ,, 2 3,520 5.19 y 17.38 do „ 3 ,2,222 3.27 J Latex ' 262 .39 .39 Machinery.—The Consulting Engineers, Messrs. H. W . Hammond & Co., made their annual inspection of the machinery and elettrical equip­ ment on the 11th and 12th March. Their report was satisfactory. The new piston and liner ordered in 1945 for the 20 B.H.P. Gardner oil engine was received and fitted in the course of. the year. The 80-90 H.P. National engine and the new Nickle Battery as made by Nife Batteries Ltd. on order were not received by the end of the year. An accident which occurred in December 1946 on the 26-inch water cooled grooved mill causing the cast iron keeps above the roller bearing blocks to crack, received attention and the keeps were renewed. The 26-in. water cooled smooth mill had the bearing journal on one of the rolls frac­ tured in June. Messrs. Brown & Co. undertook the repairs. From June* to October the mill was out of commission. A further breakdown occurred in December and the mill was again out of commission for a fortnight. While the mill was under repair the rubber was milled at Gallawatta and Pimbura estates. The breakdown of this mill adversely affected the per­ centage of sole crepe manufactured. Buildings.—The construction of the following buildings was completed during the year :— Secretary-Accountant's bungalow Junior Staff bungalow No. 12 4 sets double roomed cottages • # 2 sets double latrines. Pests and Diseases Oidium.—The incidence of oidium was not severe. One full and three partial rounds of sulphur dusting were carried out at 5 lbs. of. sulphur per round per acre. * Phytophthora.—A severe secondary leaf-fall was experienced in July. In the 9J-acre clearing, the clone PB. 183 was adversely affected and recovery was very slow. * The following trees were uprooted in 1947 :— Damage by wind ... ... 24 Building sites ... ... 12 Dry trees ... ... 15 Diseased trees ... ... 31 27 Damage by fire over an area of 11 acres in the 1938 clearing occurred in February. The damaged trees were scraped and treated with fungicide. Failure to recover necessitated the removal of 9 trees. Replanting.—The intensively tapped area of 11 acres where lining a*nd holing was in progress by the end of 1946 was replanted in May, 1947. A clonal seedling trial was laid out according to experimental requirements. The following material was used :— TJ. 1 (selfed), PB. 86 (illegitimate), PB. 5/139 (illegitimate) and GLS. 1 (illegitimate) from Dartonfield nursery. H.P. seedlings and TJ. 1 budded stumps from Nivitigalakele nurseries. Manuring.—The 1947 clearing of 11 acres received 4 ozs. saphos per tree and the 1941 clearing 61 acres received R. 215 mixture. The mature areas were manured according to programme. Cover Crolps.—The planting of Desmodium ovalifolium was continued It was suggested by the Visiting Agent that it would be desirable to plant the cuttings closer. Weeding.—Grass was eradicated. Rubber seedlings and indigenous erect covers were lopped. An extensive weeding programme started in Septem­ ber was satisfactorily completed by December. Forestry Area.—This area was manured according to experimental requirements. Natural covers causing obstruction to the movement of tappers was eliminated. Labour.—Labour was sufficient and appeared more settled towards the erid of the year. Details of. labour on check-roll at the end of the year were as follows :— Residents Non-residents Ceylonese ... 18 53 Non-Ceylonese ... 65 Average daily out-turn 109 Average daily pay 1.46 , (including dearness allowance) Health.—Record of sickness among staff and labour force :- Malaria ... ... ••• 99 cases •TJlcws ... . . . 92 „ *tnfluenza ... ... ... 195 „ Worms ... ... ... 128 „ Ankylostomiasis ... . . . 36 „ * Miscellaneous and minor ailments ... 622 Visiting Agent.—The Visiting Agent, Mr. W. A. Paterson, inspected the estates once during the year and reported favourably on their condition. Nivitigalakele Acreage Statement Rubber mature areas (1926-1935) Clearings (1939--1944) Repan'ted area — 1946 Nurseries and roads Uncultivated 681 acres 463. „ 21 „ 17 „ 16 Total 169J acres Rainfall.—146.5 ins. 23 Clearing Acreage Crop Yield per in tapping lbs. acre lbs. 1926 clearing 131 12,870 936.0 1927 103 8,442 785.3 1928 16 10,025 626.5 1935 284 16 141 566.4 1939 101 3,699 360.8 1940 93 1,926 197.5 1941 5 858 171.6 • 94 53,961 ' 574.1 Tapping.—The commercial areas were tapped on double 4. Bark con­ sumption 31-in. on each cut. Test-tapping was on S/2. d/2 system. Tapp­ ing was discontinued on the 21st February and resumed on the 17th March. The Visiting Agent commented favourably on the tapping, but recommended that the older clearings should be reverted to the double 3 system. Average daily intake per tapper was 9.3 lbs. compared with 8.6 lbs. in 1946; and the daily pay for tappers amounted to Rs. 1.56 (including dear­ ness allowance). Manufacture.—One third of the crop was manufactured in the form of smoked sheet at Nivitigalakele factory in the months of January, April, September and October, 1947. The rest of the coagulum was sent to Dartonfield for manufacturing sole crepe and other grades. . The distribution of grades is as follows :— Grade lbs. Per cent Total Smoked Sheet No. 1 7,080 13.12 - 43.12 Sole crepe 1 3,650 6.76 * • 6.76 Latex crepe 1 15,568 28.85 Latex crepe 3 6,160 11.42 y 57.22 Latex crepe 3 9,145 16.95 J • Scrap crepe 1 .6,579 12.38 1 Scrap crepe 2 3,946 7.31 y 22.90 Scrap crepe „ 3 1,833 3.21 J Machinery.—The 5 H.P. National engine was decarbonised. • Buildings.—Lines. 2 double roomed, cottages were built. Pests and Diseases. Oikliunty—The late wintering trees were severely attacked! A full round of sulphur dusting and two partial rounds were done. 5 lbs. of" sulphur per acre per full round and 3 lbs. per acre were used for the two partial rounds. • Crop.—The crop secured for the year was 53.961 lbs. This is 5,961 lbs. above the estimate and 14,407 lbs. above 1946. The 1941 clearing — 7 acres — was brought into tapping during the year. The older fields in commer­ cial tapping continued to give improved yields. The following is a summary of yield records for each field :— 29 Phytophthora.—Older clearings were attacked badly in July. Bairk Rot.—A few cases of bark rot were noticed in the areas in tapping. The usual methods of control were adopted. A summary of frees uprooted in 1947 is given below Wind damage Ustulina Building site and telephone ... Fomes . . . " Total ... 32 trees' in the 1926 and 1928 clearings were damaged by fire. These were scraped and treated with fungicide. Canker Scraping.—This was done in the 1939, 1940 and 1942 clearings. Manur ing .—The 1947 manuring programme was completed. Nurseries.—Budwood nurseries we're manured and pruned according to requirements. Seed l ing Nurseries.—Backward seedlings were manured with 12 ozs. compost and l-oz. R. 215 mixture per plant. Hand-pollinated Seeidling) Nurseries-—The disposal of material from these nurseries was as follows :— 1944 Hand-pollinated: Seedlings.—235 H.P. seedlings were planted • in the 1946 (16 acres) clearing at Hedigalla in May 1947. 2,356 buc\ded stumps representing the clones derived from the 1944 H.P. seedlings were planted (in 5-tree plots of 2 per hole) in the 1947 6f>acre clearing at Hedigalla in October, 1947. 1945 Hand-pollinated Seedlings.—3,565 H.P. seedlings were planted in the 1947 60-acre clearing at Hedigalla in October, 1947. The remain­ ing 1,200 seedlings were distributed, to nine 'Outside estates. Clones derived from these latter seedlings were planted in 5 tree plots by the estates concerned in clearings adjacent to the seedling plantations. LaWour.-f-Labour for all works was sufficient except during the har­ vesting periods. Details of labour on the checkroll at the end of the year were as fol lows:— Resident Non-resident Ceylonese ... 28 59 Non-Ceylonese ... 1 — 'Average daily out-turn 72 Average daily pay ' 1.43 (including dearness allowance) Hedigalla Estate. Acreage Statement 11 acres 14 „ 25 „ 16 ., . ... 60 • Total . . . 126 acr£s 1943 Clearing 1944 1945 1946 1947 30 1947 Clearing — 60 acres.—The felling and burning operations of 10 acres of this clearing were completed by the middle of March. Lining and holing according to experimental requirements were carried out. The distance of planting was 40 feet by 8 feet square planting, the rows running east to wegt. A further 20 acres was cleared felled «nd burnt. Lining and holing of this area was also done. A total of 5,474 holes were planted with 1945 H.P. seedlings and derived clones. Immature Areas.—Growth was satisfactory. Manur ing .—The young areas were manured according to programme. Green Manure.—Cuttings of Desmodium ovalifolium were planted out and. are spreading well. , - Bui ldings .—The following buildings were completed during the year:— Two sets of double room lines Two latrines. The following are under construction:— One junior staff bungalow Two sets of double room cottages. Cart Road .—The 4th half mile was completed in March. The road was very badly churned up on many occasions. Earlier in the year the colon­ ists used bullock carts on this road for the transport of timber and fire­ wood and latterly heavy lorry traffic was resorted to with the resultant serious damage to the road. Surface repairs were attended to monthly. Pood Production Areas under cultivation for food crops were as follows :— # Nivitigalakele Hedigalla Crops harvested during the year :— Padd.y Manioc Pineapples Advisory Services, etc. The annual summary is as under :— Chemical Department Botanical and Mycological Department Soils Department:— General Fertiliser Rationing i acre 35 acres 200 meas. 2.618 lbs. 1,365 fruits # Estate Enquiries "Visits 272 15 331 12 85 194 .12 In the Chemical Department the weight of enquiry was fifty per cent greater than that of 1946 and concerned mainly methods of procedure and machinery for the manufacture of sole crepe, defects in sole crepe and the preservation and concentration of latex. • In the Soils Department the number cf enquiries was about the same as in previous years and concerned, mainly fertiliser rationing. In the Botanical-Mycological Department incoming enquiries also showed an increase of over fifty per cent over 1946. The poisoning of rubber trees for replanting was a new item upon which a number of enquiries were made, 31 Two new advisory circulars were issued. Particulars of these appear under "Publications." Meet ings , C o m m i t t e e s , etc. The Director attended by invitation all meetings of the Board of Management, and served on the Experimental Committee, the Smallhold­ ings Committee, the Senior and Junior Staff Salaries Committees and the Financial Sub-Committee. The Soil Chemist represented the Scheme at meetings of the Fertiliser Rationing* Committee. The Director represented the Scheme at the Annual General Meeting of the Planters' Association of Ceylon and at various meetings of *he Kalutara Planters' Association in company with other officers. The Director and Mycologist attended meetings of the Matale and Kandy Planters' Associations. The Director attended several meetings in Colombo at the request of the Special Rubber Commissioners during their enquiry into the state of the Rubber Industry and prior to the publication of. the "Report of the Commission on the Rubber Industry in Ceylon." The Chemist and the Smallholdings Propaganda Officer also responded to special calls. Co-opera t ion wi th o t h e r R e s e a r c h A s s o c i a t i o n s . The long standing co-operation with the London Advisory Committee for Rubber Research (Ceylon and Malaya) was actively maintained. A Botanist appointed by their good offices became ill and withdrew just before sailing and the financial arrangements consequent upon the with­ drawal were concluded very satisfactorily by the Committee. • The fullest exchange of views has taken place on many subjects with the Rubber Research Institute of Malaya now happily restored to an active state.. • The British Rubber Producers' Research Association has continued to assist us wherever possible and Dr. G. Gee, its Director, spent several clays in Ceylon towards the end of the year during which time he was able to visit the Scheme's laboratories and estates, to see some of. the Island's rubber in company with Director, R. R. S., and to discuss with him the probable future of rubber research in the various rubber producing territories. Correspondence has also passed between the Scheme and the Research Association of British Rubber Manufacturers. In the matter of enquiries into the commercial possibilities of rubber seed oil, very active help was given to the Scheme by the Coconut Research Scheme, and close co-operation with the Tea Research Institute on matters concerned with fertiliser rationing was maintained. Publications were exchanged with research organisations in many parts of the world, • , 32 REPORT OF THE LONDON ADVISORY COMMITTEE FOR RUBBER RESEARCH (CEYLON AND MALAYA) FOR 1947 RUBBER D E P A R T M E N T Gene ra l A d m i n i s t r a t i o n • * As indicated last year the temporary arrangement made during the war under which the Imperial Institute and the Rubber Research Scheme of Ceylon shared the cost of the work carried out under the direction of «the Committee, ceased at the end of 1946. With effect from 1st January, 1947, the Boards of the rubber research organisations in Ceylon arid Malaya agreed to share in the same proportion as pre-war years the financial contri­ bution for the Committee's research and agency work. The Committee and Technical Sub-Committee held three meetings during the year and in addition the Selection Sub-Committee met on several occasions to deal with replies to advertisements issued with a view to filling the vacancies in the European Staff in the East. Many of these vacancies have existed since the end of the war, but were still unfilled at the end of the year in spite of the most extensive enquiries. The Committee were, however, successful in filling two posts in each of. the Chemical and Patho­ logical Divisions and one in the Botanical Division of the Rubber Research Institute of Malaya, Publications Publications of the Research Scheme are issued without charge to the Proprietors (resident in Ceylon), Superintendents and local Agents of Rubber estates over 10 acres in extent, who apply for registration. Extra copies are supplied # for the use of Assistants on large estate* Particulars of issues of publications are given below:— 1946 1947 Estates and Agencies ... 959 972 Subscribers ... 51 53 Exchange List ... 65 65 • Publications issued during the year were as follows:— Report of the work of the Rubber Research Board in 1946. Combined 1st and 2nd Quarterly Circulars for 1947. • Advisory Circular No. 17—Tapping Systems for Young Rubber (Revised March, 1947). do. No. 26—Clonal Seed as Planting Material (July. 1947). (Sgd.) EDGAR RHODES, Director. Research Laboratories, Dartonfield, Agalawatta, 2nd April, 1948. S3 Preliminary courses of training for selected candidates were arranged in the Committee's laboratories and those of other scientific organisations in this country. For one of the vacancies in the Chemical Division, a scholarship has been awarded to a young graduate who is being trained at the Imperial Institute, with a view to taking up duty in Malaya at the end of 1948. The Rubber Research Institute of Malaya suffered serious loss owing to the resignations of Mr. J. D. Hastings, Head of the Chemical Division, and Mr. J. H. Pidford, Chemical Engineer, to take up more remunerative employment offered by commercial organisations in Malaya. At the suggestion of the Committee, salary scales at the Rubber Research Institute have been improved, which it is hoped will result in attracting more and better qualified candidates, and place the Institute in a better position to retain the services of experienced officers'. On the recommendation of the Committee the Malayan Government appointed Mr. C. E. T. Mann, the Head of the Botanical Division of the Rubber Research Institute, to become_X>irector of. the Institute, in succes­ sion to Mr. H. J. Page who resignedQo accept the position of Principal of the Imperial College of Tropical Agriculture, Trinidad. Dr. E. Rhodes, of the British Rubber Producers' Research Association, formerly Head of the Chemical Division of the Rubber Research Institute, was appointed by the Board of the Ceylon Rubber Research Scheme as Director vice Mr. T. E. H. O'Brien, who had been compelled to retire on account of ill-health. The vacant post as Head of the Chemical Division of othe Rubber Research Institute was offered to and accepted by Mr. M. W. Philpott, Cflemist to the Ceylon Rubber Research Scheme. With a view to assisting the Rubber Research Institute in the serious difficulties which have arisen owing to the absence of experienced staff in the Chemical Division, arrangements have been made for a senior member of the staff in London, Mr. H. C. Baker, to be seconded for service in Malaya for a period of. one to two years. Since 1939 methods employed at the Imperial Institute for determin­ ing the quality of rubber have been modified considerably as a consequence of the experience gained by manufacturers during the War with African Wild Rubbers and with synthetic materials. Mr. Baker's experiences in these developments will be utilised in making similar modifications in the methods of physical testing employed in Malaya. Packing of Rubber It was suggested by a large English rubber manufacturing concern last year that natural rubber should be packed in 75 lb. bales similar to the standard package of GR-S synthetic rubber. Among the advantages claimed for this bale, as compared with the standard 2 cwt. cubical bale were reduction of distortion and greater ease of handling and stacking, on arrival in the country of manufacture. After consultation with other manufacturers it was decided to ask the Rubber Research Institute of Malaya to arrange for the preparation of a trial consignment of 20 tons • packed in bales of 75 .lb This consignment arrived during the year and was distributed by the Federation of British Rubber Manufacturers' Associ­ ations to manufacturers in the U. K. for their ^pinion. A conference was held in September with representatives of, the Federation, the Rubber T r ade 34 Association and Wharfingers to consider the reports received. The 7 5 lb. bale was strongly favoured by all classes of manufacturers, but it would cost more to pack in the East and handling charges in transit might be increased. The'representatives of the R. T. A. pointed out thSt it would not be practicable to N pack in small bales for the U. K. and in larger bales for the U. S. A., and it was agreed that little or no progress would be made unless American manufacturers also preferred the small bale. It was accordingly decided to inform the Rubber Manufacturers' Association of America, of the opinions received from British manufacturers and to ask the Association whether they would be willing to arrange for tests with a consignment of from 500-1,000 tons to ascertain the preference of American manufacturers. It is understood that some of the very large firms equipped with large size Banbury mixers able to deal with a bale of 224 lb. without cutting have previously not favoured the idea of a smaller, bale. R E S E A R C H 1. Properties o f Dry Rubber Chief attention this year has been given to a continuation of the study of the resilience of natural rubber. Resilience may be regarded as a measure of elasticity and is of considerable importance in determining the suitabilily of rubber for tyres and other important uses. The more resilient the rubber, the less is the amount of heat developed in a tyre running at speed, and other factors being equal the cooler the rubber the more resis­ tant is the tyre to internal breakdown such as "heat blow-out" tread separa­ tion and ply looseness. Natural rubber is already superior in resilience to all synthetic rubbers, and the object of the work is to increase this important advantage. It was reported last year that thorough purification of Hevea rubber leads to an improvement in resilience. This has now been con­ firmed and it has been shewn that the improvement is significant and would be of practical importance if highly purified rubber ftould be prepared economically. Purification not only involves special treatment of latex to remove protein and water-soluble impurties, but also extraction with acetone or alcohol to remove others. The total yield of rubber is thereby decreased by over 5 per cent so that apart from cost of treatment, there must be a 5 per cent increase in price to compensate for loss of yield. Moreover, it is necessary to take precautions to avoid rapid deterioration which occurs when highly purified, rubber is kept under normal conditions. Iii the circumstances, the results given by purified rubber are only of practical value in so far as .they are a guide to the preparation of good .quality material. Having established the importance of purification, an attempt has been made to determine whether the results given by rubber hydrocarbon from various botanical sources are the same. A start was made with commercial unpurified Funtumia sheet and Landolphia vine rubber from Africa in comparison with Hevea smoked sheet. The wild rubbers gave resilience results intermediate between those of Hevea and general purpose synthetic rubber. The fact that the wild African rubbers are inferior to plantation Hevea may be due to the impurities which they contain, but partial purifi­ cation by acetone extraction did not effect an appreciable improvement. Moreover, extracted Landolphia contains approximately the same percent- •age of rubber hydrocarbon as commercial Hevea smoked sliest. Although Hevea rubber is superior to wild rubbers it is not suggested that there is a fundamental difference in the chemical structure of the rubber hydro­ carbons. Molecular weight distributions and state of oxidation affecting molecular cohesion^ are more likely causes of the difference observed. It is hoped to study these problems in 1948. * The possibility of. the existence of rubber hydrocarbons of different technical qualities was further examined by dividing highly purified rubber into a series of fractions depending upon ease of solution in organic solvents. It was found that the least soluble fractions gave the best results. The insolubility of the fraction may be partly due to molecular size and also the fatt that the rubber behaves as if the molecules were lightly cross- linked (elasticity, insolubility and lack of "tack.") It is not known why a small amount of molecular bridging should produce a better rubber, but if it is true been completely worked out and tried. Much has been learned about the technique of manipulating thin, stretchy, adhesive films, and simple devices have been installed to ensure reliable and continuous service. It was hoped to complete the work in this country during 1947, but it is now expected that the work will continue .throughout 1948 after which the plant will be dismantled and shipped to Malaya for trial with fresh latex. The object of the process is not merely to effect a small reduction in cost as compared with smoked sheet but also to prepare a cleaner and more reliable rubber which cannot be confused with smoked sheet which is graded on appearance only and may or may not have come from a reliable source.^ 4. Latex TJie practical importance of the various naturally occurring non-rubber substances* in the preservation and utilisation of latex is being gradually established. Fairly detailed information has already been obtained about nitrogenous compounds and more attention is now being given to com- pormds of phosphorus. It is known that lecithin — a compound contain­ ing phosphorus — is present in fresh latex and is a surface active material likely, to be of. importance in stabilisation. Attempts were made there­ fore to ascertain how much phosphorus is associated with the rubber particles in preserved latex. Appreciable amounts of magnesium ammonium phosphate are precipitated in the insoluble sludge formed in freshly pre­ served latex, but after removal of. the sludge the latex still contains phos­ phorus as a major non-rubber constituent. Distribution experiments haye now shewn that the phosphorus is. mostly in the serum or water-phase and that it is not appreciably associated with the rubber. Occasional irregular results have been obtained suggesting that some phosphorus was Associated with the rubber-phase but it is believed that this is d.ue to the mechanical entanglement of colloidal insoluble phosphorus compounds. Even in latex preserved wholly with sodium pentachlorphenate, which would have less tendency than ammonia to hydrolyse lecithin, there was . 38 no evidence that phosphorus was associated with the rubber-phase. It is of interest that the phosphorus in dried latex films could not be extracted witfi water, dilute acid or alcohol. It is possible therefore that by the time latex reaches the U. K. or U. S. A., the whole of the phosphorus is present in an insoluble form, distributed in the aqueous phase with a tendency to "become entangled with the rubber particle. One of the practical implications of this suggestion is that phosphorus compounds are not likely to be responsible - for difficulties experienced when latex is compounded with zinc oxide. A preliminary examination of. latex for potassium compounds suggested that they were mostly in the water-phase in ammonia-preserved latex and that a larger amount was associated with the rubber in latex'preserved with sodium pentachlorphenate. A fairly detailed examination of latex with different preservatives confirms that ammonia causes the decomposition of surface-active nitro­ genous compounds and that the products pass into the aqueous phase, which as usual contains relatively large quantities of water-soluble acids as compared with latex preserved with sodium pentachlorphenate. It has been shown in previous reports that when a potassium soap is added to latex almost the whole of the surface nitrogenous material is displaced and passes into the aqueous phase. It has now been found that sterols are also displaced. This is the first direct evidence which has been obtained that sterols are at the surface of the rubber particles, although it is well known that sterol-protein complexes form mechanically stable, surface active films. The evidence indicates so far that the rubber particles in preserved latex are protected from coagulation by a complex film containing protein which is slowly being hydrolysed but is part of a complex film containing sterol and fatty acids both of which remain fairly constant. A range of substances was tested for their capacity to replace nitro­ genous materials, from the surface of rubber particles, yhe unsaturated soaps previously used tend to form peroxides which may have an adverse effect on the quality of the rubber. Of the materials tried the most effective at room temperature was sodium laurate, and as a result ^ammonium laurate is now being used in the preparation of highly purified rwbber. Co«o