and Magazine of the Ceylon Agricultural Society. 



589 



piled up on their ends. The entire tap root of 

 the dead tree must be taken out. There is no 

 occasion at this stage to leave a large hole where 

 the tree grew. It is advisable, though, to dig 

 out of the earth for a radius of a foot and to a 

 depth of two feet deep round where the dead 

 root was, and to burn all roots and pieces of 

 wood turned up so that the bed for a new supply 

 may be clean. The hole should be filled up 

 again, care being taken not to fill in bits of wood 

 so plentiful on every clearing. If the hole is 

 left open, a certain area on which the excavated 

 soil lies will escape being turned over. The 

 circular trench should be cut carefully and as 

 narrow as possible otherwise the earth taken out 

 of it will cover the inside area so heavily that 

 the "turning over" will not go down deep enough. 

 Lime should bo liberally applied and covered 

 over at tho first digging; it should be also 

 scattered in the trenches, which roust be kept 

 cleared out to the proper depth; all logs or roots 

 crossing them must be cut through. The object 

 of the trenches is to prevent the fungal threads 

 from spreading as they are not, as far as my 

 observations go, to be found at a greater depth, 

 except on tap roots, than one-and-a-half or at 

 most two feet. The inner trench is to preveut 

 infection of the ring of trees adjacent to the 

 diseased one, but as they may be already infected 

 the outer trench is dug; only a few may be in- 

 fected, consequently radial trenches are made 

 as well. In practice it will be found impossible, 

 owing to the intervention of huge logs and 

 stumps, to dig trenches as regular as the figure 

 indicates; the planter must use his discretion as 

 to where he will cut them; knowing their object, 

 he will have no difficulty in selecting the best 

 positions. The stumps near the dead tree 

 should be removed if possible; at least the soil 

 should be cleared away round their roots as deep 

 as the trenches, and an attempt made to burn 

 them: even if they are not consumed completely, 

 the fungus will be burned oft". Their lateral 

 roots should be cut off and destroyed. It would 

 be well to 



ISOLATE ALL JUNGLE STUMPS WITHIN THE 

 TRENCHES. 



These precautions must be carried out to 

 their fullest if the disease is to be eliminated. 

 Many planters are dissatisfied unless they 

 are given a simple remedy which can be applied 

 in a few minutes to a diseased tree. The pre- 

 ventive measures here suggested require some 

 labour, especially since dead trees generally 

 occur singly and widely apart. For this reason 

 and perhaps because they are not in the routine 

 of work they are postponed, not carried out in 

 their entirety, or totally neglected. Experience 

 shows there is no saving in abridging the pre- 

 ventive methods recommended, but in the end a 

 distinct loss. More trees die down and longer 

 trenches must ultimately be dug at greater 

 labour cost than if the full directions 

 had been followed when the first dead 

 tree was noticed. When unavoidably the 

 lines of the scheme cannot be fully followed, 

 the inner trench at least should be made and 

 the work recommended to be done within it car- 

 ried out. This curtailment muit not be taken 

 as recommended except in special circum- 

 stances, and only as an irreducible minimum. 



Owing to tho amount of dead wood in and 

 on the surface soil of an ordinary estate aud to 

 the length to which the lateral roots of para 

 trees so quickly spread, there is 



LITTLE USE IN MERELY TURNING THE FUNGUS 

 COVERED ROOTS 



of the dead tree up to the sun and dig- 

 ging a hole about two feet square and two 

 feet deep for a new "supply." Notwith- 

 standing advice to the contrary this is too often 

 done. The old roots and dead wood around are 

 most likely supporting the fungus, and as soon 

 as these aro reached by the young roots of the 

 "supply " infection occurs, and in a couple of 

 months there is need to put in another "supply. ' : 



The presence of root disease on a tree may be 

 detected two months or more before it drops its 

 leaves or is blown down : if it is shaken, it will be 

 found to be markedly loose in the ground. Once 

 a case of this disease has been noticed in a held, 

 a good coolie might test the trees, say, once every 

 week or fortnighf, marking those he noticed loose 

 for a closer examination by the manager. If the 

 soil is carefully cleared away a little round a 

 suspected tree the fungal threads will be noticed 

 on one or more roots if root disease is present. 

 When the tap root is not attacked, it may be 

 possible to kill the parasite by cutting off and 

 burning the diseased lateral roots and forking 

 in plenty of lime round the tree. It is safer and 

 surer to take out the tree and proceed in the way 

 recommended above, as the source of the trouble 

 is probably still existent on some neighbouring 

 stump. I think that the idea of examination, 

 by a coolie might be extended further and a 

 periodical examination, say once a month, made 

 of all trees from one to three years old. 



With regard to the 



PUTTING IN OF THE " SUPPLIES,'' 



this is dependent somewhat on the season, 

 but at least eight or ten weeks should elapse 

 before replanting. The trenches should be left 

 open about three months; if any of the suspected 

 ring has been infected, it will probably show it- 

 self before that time, but it would be wise to 

 make an examination by clearing away the soil 

 from the root to a depth of a foot or so when the 

 fungal threads will be seen if the tree is infected. 

 The upper six to ten inches of the tap root are 

 first attacked. 



On account of the large continuous areas under 

 rubber and our uniformly moist climate, an ap- 

 parently insigaificant disease may easily become 

 epidemic if not grappled with in time. Planters 

 should therefore 



IMMEDIATELY REPORT UNHE ALTHI5ESS 



among their plants. Diseased specimens should 

 be sent and full information given. Unfor- 

 tunately letters usually tell little more than that 

 the plant died. It is better to err on the side of say- 

 ng too much; nothing should be omitted because 

 it seems trilling to the writer, it may instead 

 be of considerable aid in diagnosing the disease 

 or suggesting remedies. To help planters in 

 describing diseased plants an 



" INFORMATION FORM ' 



has been drawn up and this form will 

 be sent free to any planter. The Form is not 

 meant to be exhaustive but rather to aid the 

 planter in recording bis observations j and 



