180 



The Supplement to the Tropical AgHculturist 



HYBKID, BY CROSSING CEAKA RUBBER WITH ON^ 

 OF THE NEW Ma ft i hot VARIETIES, 



which will bo better than either. It would 

 seem that there should be little difficulty in ob- 

 taining such a hybrid since all of these varieties 

 are species of the same genus, Manihot. I hope 

 to be able to devote some time to this work, and 

 shall be glad of co-operation in it. There is a 

 question with regard to the future of the Para 

 industry, to which I wish to call your attention. 

 A large number of the Para trees planted in 

 Southern India are already beginning to bear 



SEED 



and each year more and more will do so. 

 The time will rapidly come when the demand for 

 seed for planting purposes will fall far below the 

 supply, and the question will then arise as to 

 what use can be made of it. It hab been esti- 

 mated that each tree after attaining its fifth 

 year of age produces a crop of 500 seeds annu- 

 ally, and that about 200,000 seeds go to a ton. 

 If this estimate is only approximately correct, 

 the crop of seed from Southern Indian estates 

 will be very large. In a report made by the 

 Director of the Imperial Institute in 1905 it was 

 stated that the seed contains some 20 percent, 

 of an oil which was then valued at R300 per ton. 

 The seed also contains l - 07 per cent, of phos- 

 phoric acid, but its nitrogen content is not 

 stated. Now what I suggest to you is this, that 

 the seed should be collected and crushed, the 



OIL EXTRACTED, AND THE RESIDUE USED 

 AS A POONAC 



to manure the trees. This poonac should be a 

 very suitable fertiliser for rubber, since its con- 

 stituents have been gathered from the soil and 

 air by the plant itself. Further analyses, which 

 I shall hope to make, will show its exact value as 

 a fertiliser, and if the value of the oil can be 

 made to pay for the extraction and crushing, 

 estates will obviously benefit by the process. 

 My object in calling your atteution to this pos- 

 sibility at this time is that in planning factories 

 it may be taken into account, and provision be 

 made in the horse power of the engines laid 

 down for the future addition of crushing machi- 

 nery. Probably, the most economical method of 

 handling the seed would be to 



ESTABLISH CENTRAL FACTORIES 



on a co-operative plan, which would deal 

 with the seed of a district, crediting each 

 supplier with so much oil, and returning to him 

 so much poonac for each ton of seed delivered, 

 an amount which could be controlled by a 

 simple analysis of each sample which a writer 

 could be easily thought how to do by rule of 

 thumb. This is matter, however, for your con- 

 sideration. I would suggest that the advice of 

 a skilled Engineer be obtained as soon as possible 

 to recommend the best machinery for the pur- 

 pose of crushing or stamping theseed and extrac- 

 ting the oil. It seems to me that the sooner 

 preparations are made to deal with the seed, 

 which will soon be available in large quantities, 

 the more likely we are not to lose time and 

 a valuable source of manure for the rubber. 



The Chairman— said that he was sure 

 that the remarks of Mr. Anstead had opened 

 a large field for thought, and he would like 

 to hear the opinions of some of the rubber- 

 planters on the question of seed. 



"BROWN ROOT DISEASE." 



ATTACKING OUR STAPLE PRODUCTS; 



MR. PETOH'S LATEST CIRCULAR. 



The latest Botanic Gardens Circular is by Mr, 

 Patch and is on Brown Root Disease, which, 

 liays the writer, attacks Hevea, cacao, tea, 

 dadap, Castilloa clastica, Caravonica cotton, cam- 

 phor, Cinnamornum cassia, coca, and Brunfelsii 

 arnericana. Specimens of Hevea and tea killed by 

 the disease form a large proportion of the con- 

 signments forwarded to the Mycologist. It is 

 the commonest root disease of Hevea in Ceylon, 

 but it does not cause so much damage as Fomes 

 semitoatus. The latter may attack a number of 

 trees in one spot before any of them show signs 

 of disease ; but brown root disease spreads ex- 

 tremely slowly, and, in general, only one tree is 

 killed at each centre of infection, unless the dead 

 tree is left standing for two or three years. The 

 symptoms exhibited by trees attacked by the 

 disease do not differ from those of other root 

 diseases. The leaves wither and fall off, and the 

 tree or bush dies ; but, if the plant bt> dug up, 

 the special characters of brown root disease are 

 immediately evident. The roots are encrusted 

 with a mass of sand, earth, and small stones to a 

 thickness of three or four millimetres, cemented 

 to the roots by the mycelium of fungus, which 

 consists of tawny brown threads, collected 

 here and there into small sheets and nodules. 

 It is only recently that the fungus which 

 causes the disease has been satisfactorily de- 

 termined. It has been found possible, by 

 developing the fructification from diseased 

 roots, to identify it as Bymenockaete noxia. 

 Infection is conveyed chiefly through the 

 medium of old and decaying stumps. The dis- 

 ease is the only root disease of cacao known 

 in Ceylon. It develops freely whenever the 

 cacao is cut down and nearly all the cases of 

 Hevea attacked by this disease come from old 

 cacao land, which has been cleared in order to 

 plant Hevea, or from estates where alternative 

 lines of cacao have been cut out tor the same 

 purpose. In such cases it may be exceedingly 

 troublesome, not because it spreads from one 

 Hevea to the next, but because each cacao 

 stump may bf> an independent centre of disease. 

 There is no doubt that on many estates where 

 cacao and Hovea have been interplanted the 

 cacao will ultimately have to be removed. 

 When this step becomes necessary, the cacao 

 must be uprooted ; if it be cut down, and the 

 stumps be allowed to remain, root disease will 

 certainly attack the Hevea. For treatment, 

 dead trees should be removed, with as much of 

 the roots as possible, and burnt. In the case 

 of young Hevea planted on old cacao land, any 

 neighbouring cacao stump should be dug up at 

 the same time. As a rule, the whole of the 

 fungus is removed with the dead tree ; appar- 

 ently it does not travel independently through 

 the soil, but only in contact with roots or dead 

 wood. Consequently it is rarely found that a 

 neighbouring tree dies after the first dead tree 

 has been got rid of ; but to make certain that 

 the fungus is destroyed, it is advisable to fork 

 in quicklime over the affected spot. It should 



