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THE AGRICULTURAL NEWS. 



December 7, 1912 



FUNGUS NOTES. 



OOOO-NUT DISEASES IN TOBAGO. 



An interesting preliminary Report on Coco-nut cultiva- 

 tioii in Tobago, by Mr. W. G. Freeman, Assistant Director of 

 of Agriculture, Trinidad, has recently been published in the 

 minutes of the meeting of the Board of Agriculture, Trinidad, 

 for September 20, 1912. This deals principally with the 

 unhealthy condition of coco-nut palms known as root diseases 

 and calls attention to an important point of some interest 

 that had been overlooked previously, which is that the 

 diseased condition of the roots themselves is confined to the 

 horizontally spreading roots in the top 12 or 15 inches of the 

 soil, and does not extend to the deeper roots. Another 

 point to which attention is called is the existence of a 

 possibly independent disease of which the symptoms are 

 a rotting at the junctions of the leaf stalks with the stem 

 and at the base of the very young fruits. The symptoms 

 described by Mr. Freeman are not confined to Trinidad and 

 Tobago. Diseased trees whose appearance corresponds in 

 every way with the account given by him have recently been 

 examined in St. Vincent and possibly might be found in 

 certain other of the smaller islands. Part of Mr. Freeman's 

 account is as follows: — 



'I am not at present in a position to draw any definite 

 conclusions as to the cause of the trouble [i e. root disease]. 

 It is probable I think, that under varying conditions, various 

 causes result in the symptoms which are characteristic of the 

 disease It can, however, be said that the trouble is not 

 confined to areas of any particular soil. Coconut palms are 

 aflFected on "rotten rock' both on hill sides and on the flat, 

 on sands, coral deposits (coral sand), loams and heavy clays; 

 on virgin forest land, and abandoned cane lands; on places at 

 sea- level and at elevations up to 800 or 900 feet, on places 

 which have been kept clean as well as on neglected areas. 



'On most of the areas examined borings were made to 

 a depth of 3 to 4 feet and much useful information obtained 

 regarding the depth and character of the soil and subsoil, 

 and of the level of the water-table. A collection of these 

 soils and subsoils has been made. These will be retained 

 as a reference collection and should be of value to intending 

 planters in the future. 



'In certain localities unfavourable conditions of soil and 

 of water supply are probably connected with the trouble, 

 i.e., they either cause it directly or predispose the plant to 

 attack. 



'In other localities no such explanation appears to suit 

 the facts, yet the disease occurs. 



'One estate (not in Tobago) oflFers an excellent instance 

 •f the trouble, fortunately slight in amount, occurring under 

 apparently ideal conditions for coco-nuts. The soil is sand 

 to the depth, to which dug down about 4 to 5 feet when 

 water was reached. The area is drained and kept in 

 good cultivation. Trees were dying with all the usual 

 symptoms — premature dropping of leaves, falling of the 

 immature nuts, formation of the red ring in the stem, and 

 reddish brown discoloration and drying up of the upper hori- 

 zontal layer of roots. Before digging it was thought possible 

 that stagnation of water or other unfavourable soil condition 

 might be a cause of trouble. It was ascertained, however, 

 that the discoloration and decay of roots were confined to 

 those running horizontally in the upper 12 to 15 inches of 

 the soil. Those below, which run vertically down to and 

 below the water-level, were perfectly sound. A similar state 

 of affairs has since been seen elsewhere. If stagnation of 



water, or lack of awation of the soil, had been the cause the 

 lower roots would scarcely be healthy when the upper ones 

 were unhealthy. 



'Further work is necessary as to the cause of this root 

 trouble, correlated as it is with the red ring in the stem, 

 which red ring gradually progresses apparently from the base 

 of the stem upwards. 



'Then quite independent apparently of the root trouble 

 and the red ring of the stem there is the fairly constant and 

 characteristic decay at the base of the leaf where it joins the 

 .stem, and at the bases of the very young fruits. 



'This trouble has previously been investigated by the 

 Mycologist and others, but further work appears necessary to 

 determine whether its occurrence in trees suffering from "root 

 disease" is merely a coincidence or not. 



'It is important to emphasize the fact that on several 

 estates there is but little trouble at all. Others have affected 

 trees over definite, often small areas. In other cases rela- 

 tively large areas are affected Unfavourable conditions are 

 responsible, directly or indirectly, probably in some cases, 

 but there are others, as already indicated, in which this 

 explanation is not sufficient; at any rate, it is impossible at 

 present to point to any condition and say that it is unfavour- 

 able. Investigation in areas apparently well suited to the 

 palm should yield useful results. These I propose to 

 continue. The restriction in some instances of the disease 

 to the portion of the root system in the upper layer of soil 

 of practically similar character throughout appears a point 

 of some import;ince to which attention has not hitherto been 

 directed.' 



In concluding, Mr. Freeman says that this report is 

 only of a preliminary nature and that the work will be 

 continued with a view to ascertaining causes of diseases and to 

 find a practicable and profitable remedy This work should 

 be of great value not only to Trinidad and Tobago but to 

 the West Indian islands in general, and the results obtained 

 will be awaited with interest. 



THE PRESERVATION OF WOODEN 

 POLES. 



The following are some of the results of various 

 methods of treatment for preserving wooden poles 

 presented in Circular No. 198 of the Forest Service, 

 United States Department of Agriculture. Although 

 the results were not obtained under tropical conditions, 

 they are of interest in the West Indies, where more 

 attention might profitably be given to the subject of 

 timber preservation. 



Both the green and seasoned poles butt-treated with 

 coal-tar creasote by the open tank process showed practically 

 no decay at or near the ground line. 



The poles brush-treated with two coats of coal-tar 

 creasote, and preservatives sold as Avenarius carbolineum, 

 S.P.F. carbolineum, and wood creasote, showed but little 

 difference in the extent of decay. Their average loss of 

 circumference was 002, 004, 0'04 and 0'06 inch, and the 

 per cent, affected with decay 14"5, 13'6, 134 and 240, 

 respectively. The condition of these poles was next best to 

 that of those treated with coal tar creasote in the open tank. 



The poles brush-treated, respectively, with one coat of 

 preservatives sold as S.P.F. carbolineum and Avenarius 

 carbolineum showed a much greater loss of circumference at 

 the ground line than those treated with two coats of these 



