THE SUPPLEMENT TO THE 



Tropical Agriculturist and Magazine of the C. A. 8. 



Compiled by A. M. & J. FERGUSON. 



No. 1.] JULY, 1909. [Vol. V. 



THE COCONUT STEM DISEASE. 



EXHAUSTIVE INVESTIGATIONS 

 BY MR. PETCH. 



Lecture at the Agricultural Society 

 Meeting. 



At last meeting of the Ceylon Agricultural 

 Society Mr. T Petch, the Government Mycolo- 

 gist, gave an interesting and instructive, though 

 somewhat technical, lacture on the Coconut 

 Stem Disease. 



He started by mentioning the investigations 

 he had made in connection with the 



PREPARATION OF COIR 



and said he had taken samples of the 

 husks from Mirigama, where they had been 

 soaking for about three weeks, from a river at 

 Weligama, and from pools near the shore. Those 

 husks were examined for the fungus of the 

 coconut disease. In the case of Mirigama he 

 found numerous fungi, but no Thielaviopsis 

 Ethaceticus. At Weligama on the river he found 

 a little Thiclaviopsis in the husks, but not suffi- 

 cient to account for their decay; and in the pools 

 near the shore at Weligama there was a little 

 more Thielaviopsis, but again not sufficient to 

 account for decay. It was evident from the con- 

 dition of the husks and the amount of fungus on 

 them that whatever fungi were found on the de- 

 caying husks had grown there before they were 

 placed in the water. 



The water was tested as well as samples of 

 husks. It was allowed to settle and the sediment 

 was sown indiscriminately on sterilised plates. 

 In that way he could get growths of the coconut 

 disease fungus in the water from the coir mills 

 and in the water from the pools on the shore; 

 but he could not get it from the water taken 

 from the river at Weligama, because there was 

 so much sulphuretted hydrogen in it that it 

 gave a thick deposit of sulphur and nothing 

 would grow. Taking it all round, it was evi- 

 dent that the small amount of fungus spores 

 10 



found on the coir grew there before the husks 

 were placed in the water and that the decom- 

 position of the coconut husks was not effected 

 by the fungi at all. Another interesting point 

 which came out in the investigations, and which 

 was worth remembering when considering the 

 question of the 



APPLICATION OF SALT TO COCONUTS, 



was that the water from Mirigama inland was 

 salter than the water in the pools on the shore 

 at Weligama. The difference was : — Mirigama, 

 •13 per cent., Weligama '08 per cent, '05 mora. 

 The next question was : 



HOW FAR THE FUNGUS WOULD GROW ON DEAD 

 COCONUT TISSUE ? 



Of course they all knew that the leaves and husks 

 of coconuts were left lying about the estates or 

 were used in manuring; and if the fungus would 

 grow well on the tissue, it would be dangerous 

 to leave them about. His investigations 

 showed, however, that if they sowed the spores 

 of the fungus on the white tissue inside the 

 fresh husks and leaf stalks, they got a very poor 

 growth. If they took the brown husk and tried 

 to grow the fungus on the husk they got no fun- 

 gus at all. The leaves followed the same rule. If 

 they took the green leaf, they would get a small 

 amount of the fungus to grow. On the interior 

 of the stem the fungus grew in abundance. 

 That was practically the only tissue of the coco- 

 nut on which it would grow, that was, grow to 

 any dangerous extent. If they took the top of 

 the stem, i.e., the cabbage, and cut sections 

 of that, and sowed the spores of the fungus 

 on it it absolutely refused to grow. That ex- 

 plained the fact that when the stem of a 

 coconut was hollowed out by the disease, the 

 cabbage was not touched. The explanation 

 seemed to be that the fungus would only 

 grow on tissues which contained a fair 

 quantity of sugar. There was sugar in the 

 coconut stem, in the lower part, the white 

 part, but there was none at all in the coconut 



