104 



THE INDIA RUBBER WORLD 



[November 1, 1916. 



Rubber Planting Notes. 



MALAYAN PLANTERS FEAR AMERICAN INVASION. 



SOME anxiety appears to e.\ist in Malaya concerning what 

 is termed the ".'American Invasion." 

 It is asserted that representatives of American rubber 

 interests are seeking land grants in the Federated Malay States 

 and the planters fear that, should the local government grant 

 any large area to these interests, such action might add to the 

 present difficulties of the labor question in Malaya. 



Rubber estates import most of their coolies under contract 

 and have difficulty in preventing them from breaking their 

 agreements and going to work for native land owners. The 

 fear is that there would be created a fresh demand for labor if 

 large areas were to be opened up at one time. 



Besides this question of shortage of labor, there is, of course, 

 the question of wages, which the planters do not wish to see 

 higher than the present level. 



Our Malayan contemporary, "Grenier's Rubber News," sug- 

 gests that a good way to obviate the danger would be to make 

 all grants of land conditional on the Americans importing all 

 the labor necessary, and perhaps more, for the new plantations. 

 In other words, guarantees should be secured from American 

 interests to safeguard the labor in the Federated Malay States 

 from a partial or wholesale absorption by the "invaders," whose 

 motive spirit does not appear to be questioned, our contemporary 

 explaining: "An area of 100,000 acres opened up next year will 

 yield probably in 1921 only about 13,000 tons of rubber, and in 

 that year of grace the American requirements of the commodity 

 will be more than 15 times that quantity, and Britain will still 

 hold a great preponderance of power." 



DISEASES OF PLANTATION HEVEA IN CEYLON. 



I'roni tlic annual report of the botanist and mycologist of the 

 Ceylon .'Xgricultural Society, it appears that during the year 1915 

 this society received 44 consignments of Hcz'ca Brnsiltoisis dis- 

 ease specimens for examination. 



The specimens of Hevca sent in for report showed that in prev- 

 alence the diseases occupy the same relative position as in tormer 

 years, and, taken altogether, there appeared to be a general dimi- 

 nution of disease. 



The "canker" fungus. Phytophlhora Fabcri, again lieads the 

 list. Pod disease caused by this fungus was severe in some dis- 

 tricts in July; this was accompanied by heavy leaf-fall, owing to 

 the spread of the fungus to the leaf stalks. Tliis condition has 

 recently been reported from South India. 



Canker of the leaf stem in its early stages has been effectively 

 treated by light scraping and treatment with 20 per cent solution 

 of carbolineum in water. 



Canker at the collar of trees was found in the Matara district, 

 where it had nearly ringed several trees. By early and vigorous 

 treatment it is deemed possible to lessen, to a consideralile extent, 

 the ravages of this fungus. 



Towards the end of the year Fames lignosus (same as Fames 

 semitostus) was reported on several occasions from the Kelani 

 Valley. Drastic removal and burning of diseased roots and jun- 

 gle stumps where these still occur in rubber clearings is recom- 

 mended to reduce the losses from this cause. 



Decay of the renewing cortex or "bark rot," as it is more gen- 

 erally termed, was somewhat prevalent about July and November, 

 during wet weather experienced in those months. In December 

 experimental work was initiated in connection with this disease. 

 Inoculations of the freshly tapped surface of healthy trees with 

 diseased hark yielded no cases of infection. Treatment with 20 

 per cent water solution of carlmlineum appeared to mitigate the 



severity of fresh attacks, but had no immediately apparent effect 

 in arresting the rot of bark already affected. 



This disease would appear to be capable of explanation on 

 purely physiological grounds. 



Treatment of diseased areas with clay and cowdung mixtures 

 is being tried as a means of accelerating the process of occlusion 

 of exposed wood surfaces. 



One case of Poria hypolatcritia killing young Hevea was 

 observed on the Experiment Station at Ganoruwa. 



A case of Colletotriehum fieus was recorded on llevea leaves. 



The rubber research chemist of the Ceylon Agricultural Society 

 started an investigation into the formation of latex cells in con- 

 junction with the botanist and mycologist in August, 1915. This 

 research will cover a period of at least one year in order to 

 allow of observations being made in various seasons of the year. 



Observations made on samples of l)ark from numerous trees 

 indicate that the number of rows of latex cells varies to a consid- 

 erable extent, according to the height from the ground. 



INSECT PESTS OF HEVEA IN CEYLON. 



In a recent number of "The Tropical .\griculturist," the Assist- 

 ant Entomologist of the Department of Agriculture of Ceylon 

 states that Hevea rubber on Ceylon plantations appears to main- 

 tain almost complete immunity from insect ravages. Such 

 pests as have been reported during the past year were either 

 scarcely pests at all or confined their attacks to sickly or diseased 

 trees. No reason can be assigned for this, other than the one 

 put forward by Mr. Green some years ago, — that the latex acts 

 as a strong deterrent against any attempt to penetrate the bark. 

 The following pests were reported during the fiscal year 1915- 

 1916: 



Maricella dussiimieri the rubber slug, was reported as drinking 

 latex, in Udugama in March. 



Scolytida, boring beetles, were reported several times but, on 

 investigation, it appeared that the borers attack only unsound 

 bark, and are probably attracted by the fungi which grow in it 

 and not by the bark or the wood. 



Lecanimn nigrum, the black scale insect, was reported from 

 various districts in .A-Ugust and October, but in each case it 

 appeared to do little harm. 



Batoccra rubus, root and stem borer, was reported from Pel- 

 madulla in November, when it was taken from the stem of a 

 rubber tree whicli had fallen down through the damage done by 

 fhe grub. 



THINNING OUT RUBBER. 



Our Ceylon contemporary, the "Tropical Agriculturist," pub- 

 lishes the following table, showing the result of thinning out rub- 

 ber on a plantation 20 years old : 



FIFTEEN .\CRES OLD RUBBER. 



Yield Trees Rain- 

 Season. Crop. Per Acre. Trees. Per Acre. fall. 



1907-08 4,003 26; 2,419 161 145.41 



1908-09 4.020 268 2,419 161 168.49 



1909-10 5,146 343 2,419 161 137.65 



1910-11 6.594 439 2,419 161 142.64 



1911-12 6.425 428 2,419 161 167.02 



1912-13 6,532 435 2,419 161 161.41 



1913-14 6.001 400 2.180 145 196.84 



1914-15 6,596 439 1,604 106 134.97 



These figures show that profitable results follow the thinning 

 out of a plantation, even of this age; at least, under certain con- 

 ditions. There are no data for laying down definite conclusions 

 on this subject. It depends upon so many factors : the original 

 spacing, climate and price of rubber. 



The Committee of .Agricultural Experiments of the Ceylon 



