November, 1909,] 



430 



Plant Sanitation. 



he was quite wrong. He had a perfect 

 right to change the name Aleurodiscus if 

 he chose, bathe was not justified in using 

 the combination Corticium javanicum, 

 because that combination was already 

 in use for another species. When he 

 reached the end of his volume, he dis- 

 covered Zimmermann's description of 

 our "pink disease" fungus, and, to 

 put matters right, he changed the name 

 of the latter to Corticium Zimmermannv. 

 But it is not permissible to correct one 

 mistake by making another, and this 

 renaming cannot stand. Oar " pink 

 disease " fungus has first claim on the 

 name Corticium javanicum, and, if it is 

 desired to rename Henning's fungus, 

 some other combination must be found. 

 As a matter of fact, nothing of the kind 

 is needed, because Henning's fungus had 

 already been named thirty years previ- 

 ously on specimens sent from Pera- 

 deniya, and its correct name is Aleuro- 

 discus peradeniai. 



On many estates lateral branches of 

 Hevea which arose from the first six 

 feet or so of the stem have been cut off ; 

 or when the trees forked near the 

 ground level one stem has been re- 

 moved. In the majority of cases, the 

 branch or stem has been sawn across a 

 few inches from the main stem, thus 

 leaving a "stub" two or three inches 

 long. This was the method recommend- 

 ed years ago before the principles of 

 plant physiology were applied to garden 

 practice. It is now generally recognised 

 that the bark will never grow over 

 such a stub, and that the end always 

 remains exposed and affords a possible 

 point of entry for destructive fungi. 

 As a rule, the stub will die back, 

 though this danger may be avoided by 

 tarring it periodically. The current of 

 water and food passes up and down the 

 main stem, and the stub is sidetracked. 

 Now, the periodic tarring would not 

 be necessary it the bark would grow 

 over the cut surface, and the modern 

 pruner obtains this desired effect by 

 cutting off the branch as close to the 

 main stem as possible. The cut should 

 be made parallel to the main stem and 

 close to it ; it should not be made per- 

 pendicular to the branch cut off. Ac- 

 cording to the old idea, the cut should 

 be made so as not to injure the 

 bulge at the base of the branch ; the 

 modern pruner cuts right through 

 the bulge and endeavours to leave the 

 stem as smooth as possible, i.e., without 

 any projecting remains of the branch. 

 He certainly makes a bigger wound, but 

 as the bark has only to grow on in a 

 straight line, it heals over completely 

 in a comparatively short time. 



Pruning off large branches should 

 never be done by a single operation. 

 If they are sawn off close to the stem, 

 the branch falls when partly cut 

 through and usually tears off part, of 

 the stem. The first cut should be made 

 about a foot away from the stem, on the 

 under side of the branch, and continued 

 about half way through it. A second 

 cut should then be made two or three 

 inches further away from the stem, on 

 the upper surface, and this should be 

 continued until the branch is severed. 

 Finally the stub should be sawn off flush 

 with the stem. It will be necessary to 

 have two or three coolies on rubber 

 estates trained to remove dead branches 

 and prune where it is considered neces- 

 sary ; they should be taught the 

 difference between tree pruning and 

 chopping firewood. Bailey's Pruning 

 Book should be on the shelves of all 

 planters who have to deal with trees ; 

 it is the only boot which treats the 

 subject from fundamental principles. 

 Its special parts deal of course with 

 American orchard plants and are not so 

 much required here, but the general 

 parts will well repay careful study. 



The recommendation that coal tat 

 should be used for covering wounds does 

 not meet with the approval of Ceylon 

 planters. From the mycologist's point 

 of view Stockholm tar is too evanescent. 

 I am aware that it has been universally 

 recommended for tea, but there do not 

 appear to be any definite comparative 

 experiments on the subject. One planter 

 informs me that coal tar kills back the 

 branches worse than Stockholm tar, 

 while another assures me that the 

 reverse is the case. I have certainly 

 seen coal tar used in branch canker on 

 tea without any injurious effect. Either 

 will kill the green bark if applied to it, 

 and in this respect Stockholm tar is 

 liable to do most damage because it is 

 more fluid and therefore more likely to 

 run. Stockholm tar is a poor protection 

 against fungi, and in one case, in Hevea, 

 fungi grew on the cut surface three 

 weeks after its application. Modern 

 practice favours coal tar. W. J. Bean, 

 of Kew, writing on pruning in the 

 Gardeners' Chronicle, April 21, 1906, 

 states :— "The virtues of ordinary coal tar 

 — not Stockholm tar — as a dressing for 

 cut surfaces are not generally known. 

 All the raw places left by removing 

 branches or stumps of branches should 

 be immediately covered with this anti- 

 septic substance, and the coating should 

 be renewed as often as is necessary till 

 the wound is covered with new bark. 

 The best armour that a tree can have 

 to protect it against fungoid enemies 



