and Magazine of the Ceylon Agricultural Society.— Feb., 1910. 



173 



over them ; the latter has no power whatever 

 of healing wounds, and they must therefore 

 be protected to prevent weathering or fresh 

 infection. The wounds should be tarred im- 

 mediately after cutting, if the attacks of 

 "red beetle" are to be avoided. To facilitate 

 this they should first of all be scorched or dried 

 with a torch of rags dipped in od. This pro- 

 cess secures a better adhesion of the tar and at 

 the same time burns off any fragments of the 

 diseased tissue which may have been left. It is 

 not necessary to char the tissues; the main ob- 

 ject is to dry the surface. A rag wrapped for a 

 length of about two inches round the end of a 

 stick suffices for this, and gives a small manage- 

 able flame. The villager usually wants to use 

 a dry coconut leaf; but this gives a large flame, 

 which burns the surrounding healthy stem and 

 sets up bleeding which may be mistaken for the 

 stem disease. Kerosine is more manageable 

 than coconut oil and is cheaper. The use of 

 painters' lamps was recommended for drying 

 the wounds in the case of large estates, but 

 this has not, to my knowledge, been adopted. 

 The tar is applied hot ; this secures a pene- 

 tration to a depth of about 5 mm. in young 

 tissues. If the cutting has been insufficient, 

 the tree begins to bleed afresh, the liquid emer- 

 ging at the side of the old wound or through 

 the tar. In such cases the work must be done 

 again. In many instances small brittle globules 

 of resin appear on the tarred surface ; these have 

 no connection with the disease, and should not 

 be mistaken for renewed bleeding. When young 

 trees are treated, the tarred surface frequently 

 splits as the tissues dry and contract ; and it is 

 then necessary to tar them a second time, pre- 

 ferably using cold tar. It would be a 



WISE PRECAUTION TO TAR ALL WOUNDS TWICE 



with an interval of about three weeks between 

 the applications ; cold tar would adhere quite 

 well to the dry surface on the second occasion, 

 and would form a thicker covering than hot tar. 



Up to the present this treatment has given 

 good resulte. Some young trees, which were 

 cut, but not tarred, have collapsed in a few 

 weeks through the attacks of red beetle ; but 

 the danger of this seems to be small in old 

 trees. In many cases the trees have had to 

 be treated twice, but this is inevitable with 

 cooly labour ; on one estate which has 3,327 

 trees diseased. 352 have had to be treated a 

 second time. Attacks of " red beetle " are, on 

 the whole, rare, considering the number of 

 trees which have been treated ; tar appears 

 to keep off this insect. In one instance the 

 four-spotted coconut weevil bored through the 

 tar and honeycombed the underlying tissues, 

 even though these were saturated with tar 

 oils, but the excision of all the affected tissue, 

 together with the beetle larvae, prevented 

 the destruction of the tree. One planter com- 

 plained that the wounds were attacked by wood- 

 peckers, but it is most probable that "beetles 

 had obtained an entry previously. In order 



TO PREVENT INFECTION OF YOUNG TREES, 



spraying with Bordeaux mixture was recom- 

 mended. This was done on many estates, but 

 I have not been able to obtain details of the cost 

 of tho operation. fSprayoro wore uuod in ouo 



instance, but in most cases it was found cheaper 

 to apply the mixture with a brush. Experiments 

 have shown that the spores of ThieLaviopsis do 

 not germinate in a solution which contains more 

 than 0'06 per cent, of copper sulphate; spraying 

 with Bordeaux mixture will, therefore, prevent 

 infection, though the solution is not strong 

 enough to kill the spores. It was pointed out in 

 the local press that bazaar samples of copper sul- 

 phate contained about 75 per cent of iron sul- 

 phate; Bordeaux mixture made with this is 

 black instead of bluish white, and is practically 

 worthless. In most cases the amount excised in 

 the eradication of the disease is so small that it 

 can have no effect on the future growth of the 

 tree. Where long wounds have been made in 

 young trees, the supply of water and food 

 materials from the roots is interrupted, though 

 not to the extent it would be indicotyledonous 

 trees, because the wound follows the direction 

 of the vascular bundles, and though oblique, 

 hardly destroys more bundles than enter the 

 base of the diseased tissue. But since the 

 coconut is adapted for existence on a small 

 supply of water and its vascular bundles are 

 very numerous, it may be doubted whether 

 this effect will be perceptible, because the extra 

 work thrown on the remaining bundles will 

 be small when divided among so many. It 

 has been prophesied that the stem will be- 

 come gradually thinner above the wound, but 

 I can see no reason why this should occur 

 under modern estate cultivation. 



THE GREAT DANGER 



is that the stem should be so weakened 

 by cutting that it breaks with the wind. 

 This is hardly likely to occur if the wound is 

 near the base, but an estimation of its proba- 

 bility in other cases requires an investigation 

 into the tensions of a coconut stem on bending 

 — a very interesting problem, but one which 

 cannot be entered into here. There is scarcely 

 any bending with the wind in a coconut stem 

 about twenty years old ; after this the amount 

 increases with the height, the lower quarter or 

 third usually remaining immovable. The theory 

 that the palm stem does not curve in a gale but 

 bends from the base from a position to a position 

 is quite erroneous in the case of tho coconut; the 

 latter bends in a uniform curve, and the crown 

 sways like the bob of an inverted pendulum, the 

 motion of the stem being imperceptible in the 

 lower quarter or third according to the height 

 of the tree. The elongation of the stem with 

 age alters the bending moment at any point, 

 and therefore a wound which is not a source 

 of weakness at first may become such as the 

 tree grows older, quite independently of any 

 further decay at that point. Personally I have 

 only seen trees broken by the wind when the 

 stem was over 60 feet high, and the disease 

 occurred within the upper 10 feet; the number 

 of coconut palms uprooted by gales appears to 

 be far greater than the number broken. 



Holes made when cutting out "red beetle'' 

 are often filled with lime ; this serves at least to 

 prevent further beetle attacks. It has been sug- 

 gested that the holes made in carrying out the 

 present treatment should similarly be filled 

 with cement or earth, but there does not ap- 

 pear to be any advantage in this practice. In 



