A. Sharples 171 



many cases have been found recently of roots of four year old trees per- 

 meated and killed by this fungus. The jimgle stumps and timber repre- 

 sent one of the sources from which the fungus commences, for fructifica- 

 tions have been obtained from old jungle stumps (Pi. Ill, fig. 2) and 

 characteristic symptoms have been observed in lateral roots of jimgle 

 stumps exposed in areas treated for Fomes lignosus. 



It is probable that healthy jmigle trees are attacked by this fungus, 

 and spores may be blown from the jungle into the plantations. It is 

 impossible to take the measures to prevent the spread of the fimgus from 

 this source. On a clean estate, there is little danger to be anticipated, and 

 in the general scheme of treatment it may be considered negligible. 



TREATMENT. 

 This consideration of the sources and manner of infection indicates 

 that present day plantations may be divided into three groups. The 

 treatment accorded to each group varies with age. The groups are as 

 follows : 



{A) Young 'plantations not thinned out. 



(B) Platitations thinning-out with trees not ten years old. 



(C) Plantations with trees over ten years of age. 



(a) Control measures against the collar-rot caused by Ustulina 

 zonata may be initiated by enforcing strict sanitation methods from the 

 time of planting up. The clearing of the ground of rotting timber and 

 the treatment of jungle stumps is the first and immediate measure to be 

 undertaken. This will largely prevent trouble from White ants and 

 Fomes lignosus, as well as minimising that likely to ensue from attacks 

 of Ustidina zonata. Special attention should be paid to the eradication 

 of the lateral roots of jungle stumps to prevent contact infection from 

 both Fames lignosus and Ustidina zonata. This can be secured best by 

 following up the laterals from the stumps to a depth of two feet below 

 the surface. At this point they should be cut through and separated 

 from the parent stump. Clearing timber and eradicating stumps or lateral 

 roots is costly, and the difficulty of the undertaking fully appreciated. 

 Though many of the larger stumps will have to be left standing, yet it is 

 possible to clear any estate to such an extent that trouble from root 

 diseases may be reduced to a negligible quantity. 



On estates badlv aft'ected with Fomes semitostus, the elimination of 

 stumps and timber, as far as is practicable, has been fully recompensed. 

 General treatment on these lines could not be advised previously, for 

 large numbers of estates are free from '"Fomes" troubles, but few will 



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