318 



THE AGRICULTURAL NEWS. 



September 23, 1915'. 



PlANT diseases. 



A ROT OF HEVEA STEMS. 



in Bulletin 25 of the Department of Agriculture, 

 Federated Malay Stales, Mr. A. Sharpies, Mycologist to the 

 Department, givts an account of a disease of Herea l>rasili- 

 ensis, due to the fungus T'shilina zonata, Sacc. The discus 

 sion of its methods of attack has considerable general 

 interest in conne.xion with the care of trees in the tropics. 



The fungus has attained prominence during the last two 

 years as the cause of a disease affecting mostly rubber trees 

 over ten years old. The fungus is commonly found working 

 on the collar, where it causes a typical dry rot, not as a rule 

 extending far up the stem. The diseased wood on exposure 

 is found to be dry and tindery like touchwood, in advanced 

 cases falling to pieces under the pressure of the fingers. 



The disea.se is found on old plantations in every part of 

 the peninsula; the fungus does not favour any special soil 

 conditions as does the Fomes which is the cause of the root 

 disease previously most familiar in the country. 



The fungus is not confined in its attacks to the roots or 

 collar, and the observations in the bulletin under notice 

 refer mainly to its presence in the stem. It appears to be 

 strictly a wound parasite, and Sharpies traces bnck the causa- 

 tion of the present epidemics in plantations over ten years 

 old to the thinning out of trees originally closely planted In 

 this operation bruises on the bark of the standing trees from 

 contact with the branches of those which are being felled can 

 hardly be avoided. Another type of predisposing injury is 

 scorching of the bark caused by leaf fires. Into such wounds 

 boring beetles (Xyleborus) enter and set up a condition 

 ■which leads to infection by the fungus under consideration. 

 Tbf laticiferous layer, contrary to the opinion of some previ- 

 ous investigators, is said to ati'ord little protection against 

 borer once the outer layer of cork has been injured. The pene- 

 tration of the fungus is assisted considerably by the insects, 

 which bore the wood ii;i all directions and carry the infection 

 ■with them. 



There is no lack of spores of Ustulina in the clearings. 

 The fungus is one uf the principal forms occupied in the des- 

 truction of Hevea stumps and logs left in the plantations 

 after thinning out; so that it is nmch uiore abundant after 

 this pro(-ess than before. 



The general occurreiu-e of this disease is held to ju.stify a 

 much increased e.xpendituie on the removal of stumps from 

 young clearings. In the ca.se of stumps too large to be taken 

 out, the author advocates separation of the main roots where 

 they reach to a po.sition some 2 feet below the surface. 

 This with a view to preventing fungi spreading along the roots. 

 A .similar measure, the digging of a trench round a big .stump, 

 has .sometimes been adopted in the West Indies against 

 lio-sellinia disease, but has usually been undertaken too late. 

 If thorough clearing has not been carried out before, 

 n strong reoonuneudation is made that it should be attended 

 to at the critical period of thinning. 



With reference to the development of this and other 

 diseases as the plantations age, it is pointed out that 'rubber 

 planting conditions with regard to disease may bi' totally 

 difterent ten years hence from what they have been up 

 to date Hevea has been remarkably free from serious 

 diseases, but it appears possible that the troubles indicated 

 are cumulative, and the future Caunot be left to look after 

 itself.' Kor estates undertaking energetic lueasures of sani- 

 tation the future is held to be assured, and at a cost 'absiirdly 

 .small,' in comparison with the capital value of the clearings. 



W.N. 



THE ACCRA CACAO OUTPUT FOR 1915. 



The increase in the cacao exports from the Gold Coast 

 Colony during 191.^, as compared with those of the previous 

 year, viz., 24,390 tons, or 46 per cent, in quantity, and 

 £1,457, -592, or 66 per cent, in value is due principally, so 

 far as the increase in quantity is concerned, to the fact that 

 new areas came into bearing during last year. No part of 

 the increase can be .said to be due to the large proportion of 

 the 1914-15 crop that was exported in 1915, as quite as 

 much of the 1915-16 crop will be e.xported in 1916. 



The Accra exports accounted for 14,199 ton.s, or 58 per 

 cent, of this increase. This was due partly to the extension 

 of the railway and the consequent diversion to Accra of some 

 of the crop that formerly u.sed to go to Addah for shipment, 

 but a large portion of it too, was due to new areas coming 

 into bearing. Some of the cacao that formerly went to 

 Winnebah was attracted to Accra by the keener competition 

 there among buyers and the consequent higher prices, and 

 some of the crop that formerly went to C'oomassie is s^iid to 

 have been similarly attracted to Accra by the extension of 

 the railway to Koforidua. Seccondee accounted for only 

 9,983 tons, or 24 per cent, of the increase. This was due 

 partly to new areas coming into bearing and partlj- to the 

 increased yield of the trees. Winnebah and Cape Coast 

 showed but small increa.ses in their exports. 



At the beginning of the year it was feared that the- 



shortage of tonnage calling at the ports of the Colony would 



have a very bad eft'ect on the local cacao market, but as the 



result of representations made by the Government, the 



shipping companies made such arrangements that, although. 



ilelays in obtaining ships were not infrequent, yet the whole 



cacao output was shipped, or was being exported, with little 



or no loss to anybody when the year closed. 



* 



Prices, with trifling tiuctuations at times showed an upward 



tendency throughout last year At the beginning of January 

 (1915) the local price was as low as 1 \s. per load of 60 lb., 

 but by the end of that month it had risen to I i.^. 6(/. to ■ 

 16.<. 6(?. At the end of April it stood at 30s. to 33.s. which, 

 price continued, with some fiuctuations, up to November, 

 when it fell to 25.<;. to 30.«., and this was maintained to the 

 end of the year. In reference to this, it is interesting to ■ 

 note that whilst the average f.o.b. value of the 1914 exports 

 works out at £41 48 per ton, the corresponding figure 

 for 1915 was £4725 per ton. This is due solely to 

 the market fluctuations and in no way to an)' improvement in 

 the quality. Meanwhile, the relative value of Gold Coast 

 cacao in the Home markets, according to the Comptroller, 

 does not give much reason for jubilation. At the end of 1913 - 

 it Sold at 56.'j. per cwt. as compared with 70s. for Trinidad, 

 52«. for (irenada, 85,<. for Ceylon, and 6(i<. iVir Ecuador. At the- 

 end of 1915 the market reports .show that the Gold Coast 

 rates in the Home market were 67s. dd. to S3s. , as against 

 92s. to 9()s. for Trinidad, 85s. to 95.^•. for Kahia, and 92s. 6rf. 

 to 94s. 6rf. for Guayaquil. For all Mr. Archer's disappoint- 

 ment, it is generally agreed, however, that whilst the increa.se 

 in the output of cacao from the Gold Coast is one of the 

 wonders of the cacao world the price it has all along sold 

 at and is still realizing leaves very little to be ashamed of. 

 [Tropicid L'ft'.) 



