Fkbrl-arv 1, 10:0.1 



THE INDIA RUBBER WORLD 



321 



Rubber Planting Notes. 



PLANT DISEASE ALARMS UNWARRANTED. 



While admitting that the question of ruhber diseases in tlie 

 Far Eastern plantations is important and noting that everyone 

 can see the marks of them on the trees and that the reason 

 why many estates are reported to be immune is that they have 

 not been examined scientifically, "The India-Rubber Journal" 

 is inclined to be ironical about disease scares, ascribing much 

 of their severity to the imagination of the local press in enumer- 

 ating the successive scourges which have not interfered with 

 the development of the plantations. 



The first alarm was over Fames and other fungi that attacked 

 the roots ; then came the black stripe canker which affected 

 tapped trees ; this was followed by Ustulina, and the latest is 

 the brown bast disease, of which the cause is yet undiscovered. 

 The pink disease alone so far, though ever present, has not 

 aroused concern. So long as no leaf disease attacks Hcvea 

 brasilicnsis, rubber producers need not fear. 



RUBBER RESEARCH IN CEYLON. 



Rubber research was interfered with by the calling away of 

 investigators for war service. The Rubber Growers' Association 

 did not favor the plan of having all research combined and 

 directed from a central body in England. Plans are formed for 

 training young men to inspect the rubber districts in the way the 

 tea districts are now inspected. A book on "Rubber Research in 

 Ceylon" is to be published soon ; it is made up of the bulletins 

 that have been issued by the Ceylon Research Commission. 



The investigation of rubber diseases is kept up in Ceylon, 

 Professor T. Petch at Peradeniya having received 232 speci- 

 mens. He reports that brown bast has spread throughout all 

 the rubber districts, though it is more common in the drier 

 regions. The cause and nature of the disease has not yet been 

 fully decided upon, and the measures taken to overcome it 

 seem to have varying success in the different provinces. 



INVESTIGATIONS OF HEVEA IN MALAYA. 



Variation in the llcvea brasilicnsis that grows in Malaya 

 have been, studied closely by Stafford Whitby, who gives the 

 results in the "Annals of Botany." His investigations concerned 

 the amount of rubber yielded by individual trees of the same 

 age and growing under the same conditions, and also the pos- 

 sible relation between the girth of the trunk and the yield 

 of rubber. About 1,000 seven-year-old trees in their third year 

 of tapping on a normal plantation of about 13 acres, were under 

 observation. As the seed from which the eastern plantations 

 were grown was not selected seed the results are of particular 

 interest. 



Great variations were found in the rubber content of the 

 late.x of different trees, but the strength of the latex was con- 

 stant for each tree, as a rule. Some trees yielded only 23 grams 

 of rubber to 100 cubic centimeters of latex, and others yielded 

 54 to 55 grams ; the mean of 243 trees examined was 36.58 grams 

 to 100 cubic centimeters. Moreover, the older the tree the 

 larger the rubber content; Mr. Whitby sets the yearly increase 

 at V2 gram. 



The yield of individual trees was found to be comparatively 

 constant, a tree that was a high yielder at one time continued 

 to be a high yielder through the two years of observation. The 

 results were drawn from the examination of 1,011 seven-year-old 

 trees. A large number of trees yielded from nothing to two 

 grams a day, a few yielded over 27 grams; the average was 

 7.12 grams. Less than a tenth of all the trees yielded 28 per 

 cent of the total, while over an eighth gave only 2.9 per cent 

 of the yield, and certainly did not pay for tapping. Four excep- 



tional trees yielded 41.45, 41.56, 41.72 and 42.77 grams a day. 

 The possibilities of improving rubber yield by a proper selection 

 of seeds seems clear. 



The investigation into the girths, while it showed tliat trees 

 with large trunks were good yielders and those with small 

 trunks poor yielders, did not determine the matter clearly enough 

 to justify destroying trees. The investigation of A. A. L. Rut- 

 gers in Sumatra, printed in the "Archief voor de Rubbcrcultuur 

 N ederlandsch-Indie," agree with Mr. Whitby's results. 



It is not possible under present plantation conditions, where 

 high and low-yielding trees are intermixed, to determine whether 

 seeds from a high-yielding tree will produce other trees that 

 are also high-yielding. To decide that, the young trees should 

 be segregated so that the pollen from the poor yielders cannot 

 fall upon them. 



SCIENTIFIC RUBBER PLANTING IN INDOCHINA. 



At Saigon, in French Indo-China, an official rubber laboratory 

 has been established as a branch of the local Pasteur Institute, 

 with Dr. Lahille in charge of it. Governor-General Maspero took 

 on himself the responsibility of adding the money needed to the 

 budget. The Scientific Institute of Indo-China has also been 

 brought into being, whose agricultural department will supervise 

 Hcvca culture as one of its functions. Both laboratory and 

 institute will work, so far as rubber is concerned, in close con- 

 nection with the newly instituted rubber department of the Mar- 

 seilles Colonial Institute, which is in charge of Dr. Van Pelt. 



WHITE ANT EXTERMINATOR. 



The termites or "white ants." as they are usually called, are 

 troublesome pests on rubber plantations where they enter the 

 roots of the trees and often excavate the stem. The depth of 



Destruving White Ants on a Rubber Plant.xtiun 



the insect burrows varies from a few inches to four feet but 

 the length is considerable in some cases, having been traced 300 

 feet from the nest. 



Soil insecticides are said to be practically useless in exterminat- 

 ing these pests and fumigation is the only satisfactory method. 

 A poisonous white ant powder is heated in a machine compris- 

 ing a charcoal furnace, generating fumes that arc forced into the 

 burrows by means of an air pump. All openings being sealed 

 with clay, the fumes will destroy the ants and eggs in a few 

 days' time. (The Four Oaks Spraying Alachine Co., Four Oaks, 

 Sutton Coldfield, near Birmingham, England.) 



