and Magazine of the Ceylon Agricultural Society. 



405 



carrying salts to the leaves, an abundant supply 

 of water is required in every part of the plant 

 body to keep the body cells in activity. All the 

 water required by a plant is taken in by its roots. 

 The roots which do this work are for the most 

 part not the main roots but the finer rootlets. 

 As we have seen above a large proportion of 

 these are found to have rotted in disease trees, 

 with the result that the water-supply is di- 

 minished. In a tree such as the coconut 

 palm the effect of this would naturally 

 not be evident in the 6tem, but would be 

 visible first in the leaves. This accounts for 

 the early symptoms of drooping of the leaf- 

 lets and 



FLACCIDITY OF THE LEAF STALK 



so that it bends away from the crown. At the same 

 time interference with the food-supply causes 

 the leaves to lose colour. The yellowing of 

 tho crown which is the most evident symptom 

 of the disease is thus due to the combined 

 effects of drought aud insufficient food. Hence 

 it is that though an appearance of recovery 

 is said to be frequently visible after heavy 

 rain, the effect, as it is only due to a tem- 

 porary increase in available water, disappears 

 as rapidly as it came. The period of fruiting 

 of a tree throws a heavy additional strain on 

 its resources. This is chiefly in the matter of 

 food-supply. Hence unless the feeding mecha- 

 nism of the tree is in perfect order the fruit 

 is not properly developed. For the first season 

 or two of scarcity the reserve resources pos- 

 sessed by every tree may be sufficient to allow 

 a fair proportion of fruit to ripen. This, 

 however, is only done at the expense of the 

 " capital " of the tree and in reality hastens its 

 deterioration. Later on food becomes insuffi- 

 cient for any formation of fruit and the 

 tree becorres barren. This is exactly what 

 happens in coconut disease and is made mani- 

 fest first by a diminution in the number of nuts 

 on each bunch, then by their dropping while 

 immature and finally by their entire absence. 

 As a larger number of leaves become incapable of 

 performing their proper work of manufacturing 

 food, the leading shoot becomes stunted. The 

 still unexpanded leaves of the bud turn yellow 

 and dry up at the extremities. This withering 

 extends backwards until, in extreme cases, the 

 bud itself withers, rotting sets in and the crown 

 falls off. Such a termination may not be 

 reached fo* years ; localities, such as Alleppey, 

 where disease has existed for twenty years, 

 have as yet had comparatively few deaths. 

 Palms of every age are attacked. In Minachil 

 numbers of diseased seedlings a year or 

 two old were found. Very old palms 

 appear to escape longest, probably on account 

 of their large root area. Still I saw a 

 few trees, said to be about 



A HUNDRED YEARS OLD, WHICH WEEK UNDOUBT- 

 EDLY DISEASED. 



The intensity of the disease differs gieatly in di- 

 fferent localities, lnthe sub-montane area around 

 Minachil death is a frequent termination. In 

 Alleppey and Changanachery deaths are rare. 

 In the former the attack first began in areca 

 palms and subsequently extended to coconuts. 

 It spreads most rapidly and is still most severe 

 in the low-lying, badly drained lands along the 



valley of the Minachil river. Gradually the hill- 

 side gardens were attacked, until at the present 

 time scarcely a garden between Erattupetta 

 and Pulliyanur is free from it. In areca palms 

 it runs its course more rapidly than in other 

 species, This is probably due to a variety of 

 causes. In the first place there is little or no 

 attempt at cultivation in the areca gardens. The 

 nuts are self-sown and come up densely through 

 a heavy undergrowth of weeds. They appear 

 to receive little attention at any period of iheir 

 growth. The palms are very close together, six 

 or eight hundred to an acre. They are smaller 

 and probably more delicate than the coconuts. 

 All these circumstances favour the disease and 

 it spreads rapidly once it gets a footing. In one 

 garden visited, only thirty areca palms had 

 survived out of six hundred. Death has been 

 known to occur in three years from the fiist 

 attack, but the usual period is five or six years. 

 In coconuts young palms may be killed in five 

 years, but this is exceptional. Eight or ten 

 years appears to be a more usual period, while 

 in very many cases the disease progresses 

 enough to cause barrenness, but fails to kill the 

 tree outright. Thus in one large garden only 

 two hundred coconut palms were in bearing 

 out of about two thousand, while the actual 

 deaths were not numerous. Recovery in either 

 areca or coconut palms, once they have taken 

 the disease, is said to be unknown near 

 Minachil. Near the coast at Alleppey very few 

 trees have been killed. The area affected here 

 is an almost continuous block of about twenty 

 five acres in extent. In part of this somo pro- 

 prietors have seventy or eighty per cent of their 

 palms diseased. Here coconuts were first 

 attacked and areca palms, which are less grown, 

 subsequently. I was shown several palms 

 which have been 



DISEASED FOR MORE THAN TEN YEARS WITHOUT 

 SUCCUMBING. 



As regards recovery opinions were conflict- 

 ing. In some cases a progressive recovery 

 lasting for five or six years was said 

 to have occurred. Others said that such 

 recovery was temporary and that the 

 palm never succeeded in entirely throw- 

 ing off the infection. At Changanachery 

 in the backwater tract the disease was 

 similarly of a mild type as compared with Min- 

 achil but was widespread. Deaths were rare 

 but the loss in yield in individual gardens was 

 over 5(J per cent. A temporary recovery had 

 been obtained by one man who applied lime to 

 the roots ; this only lasted for about two years 

 and the yield again dropped. Hore, as at 

 Minachil, low-lying lands were most severely 

 attacked, but gardens on higher land were not 

 immune. Where the soil is sandy, the progress 

 is slower than on laterite. The above account 

 shows that the disease is worst in the heavy 

 alluvial valleys and poor laterite hill soils on 

 the sub montane tract. It is widely distributed 

 but less severe in the neighbourhood of the back 

 waters being apparently worst on poor laterite 

 ridges and badly drained hollows. It is least 

 severe on the sandy soil of the littoral. 



Spread has probably occurred from one or a few 

 centres which were early attacked. The evidence 



