Vol. X. No. 239. 



THE AGRICULTURAL NEWS, 



197 



NOTES ON SOIL AND PLANT SANITATION 

 ON CACAO AND RUBBEH ESTATES. By Harold 

 Hamel Smith. John Bale, Sons <(; Danidsson, Ltd, London. 

 10s. net. 



In its 630 odd pages, after an introduction l)y Professor 

 Wyndhani Dunstan and a preface by the author, this book 

 contains sections comprising the subjects of estate practice 

 before and after the planting of cacao and rubber, the use of 

 protective belts, the utilization of waste products on estates, 

 the possibility of employing inoculation against pests and 

 diseases, the diseases and pests of cacao and rubber, the dif- 

 ferent varieties and species of cacao and rubber, and the 

 preparation of the products for the market; with reference to 

 the last, the volume concludes with a section giving an account 

 of mechanical appliances for use on estates in connexion with 

 these crops. 



The question of protective belts on estates for the pre- 

 vention of the spread of disease is important, and is treated 

 at some length, while good illustrations are given from 

 ▼arious parts of the world, of the ill ert'ect of the destruction 

 of trees over large areas. As regards estates, the best sug- 

 gestion is the planting of such belts with other rubber trees, 

 for Para, with timber plants or with Eucalyptus; where forest 

 has to be cleared, belts of this maybe left for the same 

 purpose. It may be mentioned that cacao is quite unsuited 

 as a belt for Hevea; both are subject to the same diseases, 

 and neither would protect the other, so that, from the point 

 of view of distributing risks, the combination is ineffective. 

 As is pointed out by the author, cotton, either alone or under 

 cocoa-nuts, is unlikely to grow in good Hevea or cacao land. 



The section on the manuring of cacao is useful, and the 

 same is true of what follows in connexion with plant foods, 

 manuring for rubber and green manuring. In regard to the 

 one dealing with the question of inoculation as a cure for 

 pests and diseases, agreement must be expressed with Anstead, 

 that at present the method is not practical>le: no fungus anti- 

 toxins are yet available, and local fungicides would probaljly 

 kill the part of the tree to which they were applied, without 

 completely destroying the fungus. The elfect of injections of 

 iron, for chlorosis, is no argument on this question. The 

 inoculation of scale insect.i with para.-^itic fungi is also a some- 

 what different matter. In relation to this, it may be pointed 

 out that the work which is described was all originated by 

 the Imperial Department of Agriculture, and not by the 

 Department of Agriculture in Grenada. 



In the section on the tapping of rubber, the subject; is 

 treated in a broad manner, with .^onie useful illustrative 

 facts; that on rubber diseases al.so contains some particularly 

 helpful references to literature relating to the subject. (It 

 may not be out of place to draw allintion to the mixed 

 metaphor which is quoted in italics on page 352.) The 

 treatment of the matter dealt with in relation to Castilloa is 



fairly thorough. In the Ceara section, the subject receives 

 some of the most detailed attention that is given to any in 

 the book. Finally, taking the main sul.ijects generally, it 

 should be stated that the section on mechanical appliances is 

 very good, and well illustrated. 



It is a matter for regret that there is a large confusion 

 of ideas indicated in the section on cacao disease. Among 

 other matters, the brown or black rot disease of pods 

 {Pliytopthora Faberi) is confused with 'brown root' disease of 

 Ceylon (llijmenochaele noxia); this confusion is clearly in the 

 mind of the author and not due to a printer's error: it occurs 

 in the bililiography on page 3.56, as well as on page 199. 

 Then again, the manner of quotation of the Trinidad authori- 

 ties on the subject of 'brown rot' disease would make it 

 appear that the work was done in that island, whereas the 

 information on page 200 is really taken from Petch's report 

 on 'brown root' disease, in the Ceylon Adminstration 

 Reports for 1906. Extracts from this were sent by Hart to 

 the Trinidad Agricultural Society, and printed as Society 

 Paper No. 261 in the Proceedings of the Agricultural Society 

 of Trinidad and Tobaqo, Vol. Vll, p. 179. Further, 'I', in 

 the sentence beginning 'In spite of its frequent occurrence 

 I have not' clearly refers to Fetch, and on page 202 the 

 same authority is responsible for what is given on the fungi 

 connected with canker. 



In any case, the information is out of date, as 

 Fhytophthora Faheri is now recognized as the cause of the 

 disease, in Trinidad and Ceylon. It may be said that the 

 whole section on cacao diseases would have gained by being 

 treated much more concisely, while the confusion detracts 

 seriouslj- from its value. There is the additional point that 

 the importance of the connexion of the diseases of this crop 

 with those of Hevea should have been emphasized. As is 

 stated, the information regarding the latter had to be cur- 

 tailed owing to want of time. What has been said in regard 

 to the diseases of cacao should show the importance of the 

 careful treatment of those of Hevea, when they come to be 

 included in future editions of the book. 



A glance at the synopsis of contents will make it evi- 

 dent that the arrangement of the subjects is .somewhat con- 

 fused: there is a certain amount of carelessness in giving 

 names; and the work generally would have been more valu- 

 able if it had been compiled in a less diffuse manner. This 

 does not prevent the existence of the fact that the general 

 principles advanced in the book on the subject of estate 

 sanitation are thoroughly sound. In relation to this matter, 

 the question of international legislation, which is strongly 

 advocated by the author, is of much importance, notwith- 

 standing its difficulties, and worthy of careful consideration. 

 Attention must also be drawn to the excellent suggestion 

 that a trained observer should be .sent to Brazil to do work 

 in connexion with insect pests, though the word Entomolo- 

 gist, on page XX, was surely meant instead of Mycologist. 

 A valuable characteristic of the book is that plenty of good 

 references to literature are given, as well as several selec- 

 tions from good papers and articles having relation to the 

 subjects with which it deals. The index forms a fairly 

 efficient means of reference, though its attention to the differ- 

 ent subjects is somewhat uneven. 



Altogether, the work forms a useful means of giving 

 general information to those interested in cacao and rubber, 

 more particularly from a plantation point of view, and is 

 a guide to much of the more recently published literature 

 on plant diseases — matters which make it indispensable to 

 those for whom it is intended. 



