OS 



[August, IflOtJ. 



observed should be removed before they 

 have time to flower. The same species 

 are also abundant upon jungle trees in 

 the neighbourhood of tea clearings and 

 elsewhere, and for this reason anything 

 like the total extermination of the pest 

 is undoubtedly quite out of the question. 

 It may perhaps be worth while to 

 remove Loranthus plants from the 

 fringes of the jungle bordering upon a 

 tea estate, since the seeds are more 

 likely to get carried on to the tea from 

 such a position. 



Loranthus is not a plant which is 

 likely to develop into a rapidly spread- 

 ing pest after the fashion of some 

 fungus diseases. Its rate of reproduc- 

 tion is so comparatively slow and the 

 plant itself is so comparatively con- 

 spicuous that, with a little trouble, it 

 could readily be kept in check upon such 

 a closely cultivated crop as tea, even if 

 the parasite were to become very much 

 more persistent in its attacks than is the 

 case at present. Nor is Loranthus likely 

 to spread in any abundance over large 

 distances, since it is dependent upon one 

 or two species of birds for its distribu- 

 tion, and therefore unlike a fungus, the 

 spores of which may be carried to 

 indefinite distances by wind. 



As regards the method of dealing 

 with Loranthus as a pest there is only 

 one remedy, and that is the knife. 

 Whenever the plant is seen upon a tea 

 bush or upon any other plant, the life of 

 which is valued, the parasite should be 

 immediately cut out together with a 

 considerable portion of the branch which 

 bears it. The haustoria of the parasite 

 may travel down to quite a considerable 

 distance below the point at which the 

 leafy shoot emerges, and if any of this 

 rooting portion is left within the branch, 

 the part remaining will be capable of 

 giving rise to fresh shoots of the Loran- 

 thus. By close inspection of the section 

 of a branch it can generally be ascer- 

 tained whether the parasite has been 

 completely removed or not. It is also 

 advisable to remove the Loranthus as 

 far as possible from other trees in 

 accessible places near estates, and badly 

 affected trees may be cut down. 



We take this opportunity of drawing 

 attention to some extracts made by Mr. 

 Petch from a paper published by Pro- 

 fessor Keeble in the Transactions of the 

 Linnsean Society as the result of obser- 

 vations made during a visit to Ceylon. 

 These extracts deal chiefly with the 

 fertilization of the flowers of Loranthus 

 and with the distribution of its seeds by 

 birds. These extracts appear on a later 

 page of the present issue of the Tropical 

 Agriculturist 



R. H. L. 



Reviews. 



THUMB-NAIL PRUNING AND 

 DISEASE. 



[Note sur la ramification de l'Hevea 

 par la taille et par l'effeuillage par M. 

 A. de Ryckman. Journal d 1 Agriculture 

 Iropicale, No. 91, Jan. 1909, pp. 5-7. J 



" The development of the branches of 

 young heveas is always a subject of 

 engrossing interest to planters. There 

 has been much discussion on this point, 

 but no completely satisfactory solution 

 has been reached. The natural tendency 

 shown by young heveas to produce a 

 tall stem certainly retards their growth 

 in diameter, and consequently in tap- 

 pable area. It does sometimes happen 

 that a slender tree gives a greater yield 

 of rubber than one with a short thick 

 main stem, but that is not the general 

 rule. 



"H. Wright has advised pollardicg the 

 stem at a height of about twelve feet. 

 In this way, an excellent length of trunk 

 for future tapping, and a much more 

 rapid growth in thickness are effectively 

 produced ; but the practice appears to be 

 attended by some disadvantages. 



"After the pollarding, a crown of young 

 branches appears below the wound, form- 

 ing a head like that of a pollard willow 

 at a single point of the stem. Two only 

 of these shoots are preserved in order to 

 form the fork of the tree ; the suppres- 

 sion of the others naturally causes 

 numerous wounds which, if they are 

 not immediately covered with some pre- 

 servative, afford as many points of at- 

 tack for insects or fungus spores. The 

 first pruning must generally be followed 

 by a second, sometimes even by a third, 

 whence occur fresh wounds as dangerous 

 as the first, 



"In support of his theory, H. Wright 

 correctly observes that the foliage, thus 

 increased, exerts, a favourable influence 

 on the growth of the trunk. But may 

 not the following consideration be set 

 against this ; is a very young tree capa- 

 ble of supporting without injury an 

 abnormal augmentation of its foliage ? 

 Indeed, though the leaf is the organ in 

 which the sap is elaborated, it is also the 

 chief organ of evaporation ; from which 

 it follows that in multiplying the num- 

 ber of leaves, the evaporation (trans- 

 piration) is increased tenfold. Hence it 

 may happen that the equilibrium be- 

 tween the root system and the foliage 

 may be disturbed, and that the tree may 

 hereby acquire a more marked predis- 

 position to disease, in spite of its appa- 

 rent vigour. This is only a personal 

 hypothesis deduced from my observa- 



