408 



The Supplement to the Tropical Agriculturist 



Farm at Trivandrum and this appears to be 

 work which he could carry out. A small garden 

 with sufficient moderately diseased palms 

 for experimental purposes might be taken up, 

 and a series of experiments planned with the 

 ordinarily available manures, supplemented by 

 ammonium sulphate, lime, sulphur and sul- 

 phate of iron. Each of these should be tested 

 separately, not in combinations. 



{i) Improving the General Health of the 

 Palm. — Cultivation in coconut lands might 

 be very greatly improved. This is particu- 

 larly the case in the inland districts, such as 

 Minachil taluk. In these, manuring is practised 

 only to a limited extent ; draining is wholly 

 unattended to ; cultivation is neglected. Tho 

 common condition in the badly diseased 

 gardens along the banks of the Minachil 

 river is a dense undergrowth of weeds and 

 low jungle, through which the palms grow 

 as best they can. There is no drainage, 

 though the land is low lying, heavy, and in 

 urgent need of it. Drainage in these lands 

 would materially improve the root develop- 

 ment and give the plant a chance of throw- 

 ing out new feeding roots to replace those 

 destroyed. The great root development of 

 palms on the coast soils is probably the rea- 

 son why they are less severely affected by the 

 disease. The presence of a dense covering of 

 weeds on the soil keeps the latter badly aerated 

 and probably promotes the growth of the para- 

 site. Cultivation would break up the soil and may 

 be expected tu produce a directly harmful effect 

 on the parasite, apart from improving root deve- 

 lopment. The effect of manuring on the disease 

 should be studied. It is certain that anything 

 that stimulates the growth of the palm will im- 

 prove its resistance to the disease. It is how- 

 ever, possible that some manures, such as cattle 

 manure or other nitrogenous fertilisers, may 

 also stimulate the growth of the parasite and 

 might do so to an extent that would more than 

 counterbalance the improvement of the palm. 



(3) Search for Disease-resistant Varie- 

 ties.— A number of varieties of the coconut palm 

 are known. Several are enumerated in Ferguson's 

 Ceylon Manual " All about the Coconut Palm." 

 I was not able to ascertaiu what varieties are re- 

 cognised as distinct in Travancore nor whether 

 any have shown powers of resisting the disease. 

 Enquiries amongst intelligent growers might 

 elicit valuable information in this direction. It 

 is well known that some varieties of a plaint 

 often resist disease much better than others, and 

 if such a variety could be discovered amongst 

 the coconut palms of Travancore, its value would 

 be very great. 



(6) Measures to Prevent the Introduc- 

 tion of the Disease to Neighbouring Terri- 

 tories. — There is a very large water-borne trade 

 in coconut produce with the neighbouring State 

 of Cochin. Intercourse with the British districts 

 of Coimbatore on the north-east and Tinne- 

 velly on the east is less, and there is probably 

 little export of raw coconut produce elsewhere 

 than to Cochin. As the latter is a largo coco- 

 nut grower and adjoins on the north the exten- 

 sive coconut districts of British Malabar, it ap- 

 pears that stringent regulations are required to 

 prevent theinfeotioD of these areas. For practi- 



cal purposes it is probable that a sufficient safe- 

 guard would be provided by prohibiting the 

 entry of living coconut plants (seedlingsare.it 

 is believed, sometimes exported) and of roots 

 (said to be used for fuel by metal workers, and 

 also as medicine). I am strongly of opinion 

 that the export of these should be forbidden in 

 Travancore and that all coming from Travancore 

 should be declared contraband by Cochin. From 

 the nuts, coir, oil and, in fact, all the above 

 ground parts of the tree, no danger need be 

 apprehended. 



The following notes on some othe,r disease of 

 coconuts observed in Travancore are added to 

 enable them to be distinguished from that des- 

 cribed above. They are at present of less im- 

 portance than the latter, though in the aggregate 

 responsible for a good deal of damage. As their 

 causes and treatment are different in each ease, 

 it is necessary to be able to recognise them 

 wherever active measures against coconut disease 

 are proposed. 



(1) Leaf Disease Caused by Pestalozzia 

 Palmarum. — This disease is due to a fungus 

 which attacks only the leaves. It first becomes 

 visible by the apperanco of little transparent 

 whitish spots on the leaves. These may be only 

 few in number or may, in bad cases, be very 

 numerous. They gradually increase in size and 

 become at first yellowish and then white in the 

 centre. As they grow, two or more frequently 

 run together, leading to large irregular areas of 

 dried-up tissue on the leaf. The margins of 

 leaf often dry up in this manner and, as the dead 

 parts crack and fall off easily, the leaflets be- 

 come ragged along the edges. Around each 

 spot is a dark brown line, outside which is a 

 ring of pale, green or yellow tissue where 

 the healthy part of the leaf is being invaded 

 by the fungus. Tho chief differences between 

 the root disease and this are that in the for- 

 mer a large part of the leaf turns pale and 

 then yellow, without the formation of definite 

 white spots. The ends of the leaflets droop 

 and wither but turn brown instead of white 

 at the tips and edges, and do not become 

 ragged. The central shoot is stunted and even- 

 tually withers from above downwards, whereas 

 in the leaf disease the central shoot is little 

 affected except in bad cases. A few spots of 

 leaf disease are common on coconuts all along the 

 Malabar coast. In young gardens it may be- 

 come a serious blight, as young palms are 

 more affected than old. In one garden, where 

 the palms were about seven years old, the 

 appearance from a distance resembled that 

 produced by root disease, but closer examin- 

 ation showed no trace of the latter. There was 

 no drooping of the loaf ends ; all the leaves 

 were dotted with white spots surrounded by 

 a yellow ring, so close together that the 

 leaves looked quite yellow from a little dis- 

 tance. Severe outbreaks of this disease have 

 been reported from Java and elsewhere. They 

 have only occurred on young tieas and ex- 

 cept in the latter the fungus does not appear 

 to do much harm. It is worst in Travan- 

 core on neglected young palms and in the 

 garden referred to above an application of 

 manure had resulted in a marked improve- 

 ment. Cultivation and manuring appear to be all 

 that are required in most cases for lie checking. 



