66 



The mycelium of the ^^llg^l^s almost always pi-odiiees ii very 

 cbaracteristic mottled fan-like appearance in the bark, and ap- 

 pears to penetrate tbrongh the tissues of the bark but a short 

 distance, if at all, beyond tliis discolored area. The mycelium 

 also penetrates the sapwootl very freely, when the disease reaches 

 as deep as the wo<td, as it meiicially (h)es sooner or later; but, 

 unlike its effect in (iic liai-k, ii(» i>ronouiiced discoloration is pro- 

 duced in the wood, and it is impossible to determine with the 

 unaided eye the approximate limits of the mycelium, as in the 

 case of the bark. 



In all efforts to control the disease without destroying the 

 tree, it is of course necessary to gouge out this disease infected 

 sap wood. The depth to which it is necessary to remove it can- 

 not at present be definitely stated, as insufficient time has 

 elapsed to demonstrate this point experimentally. ]Many cut- 

 tings, some with the sapwood partially removed from beneath 

 a lesion, and others with all of it removed, are now being watched 

 for results. However, in a diseased spot from three to four 

 inches in diameter ajiparently at least three annual layers of 

 wood in the centre of the diseased spot must be removed. 



Of course where sapwood is cut, enormous numbers of minute 

 tubes, which conduct the crude sap from the roots through the 

 trunk and branches to the leaves, are severed, and, should the 

 cutting happen to have been done during Avarm, dry weather, 

 it often hajjpens that one or more branches directly above the 

 cut-out area will show much wilted leaves within an hour or 

 two. This is a direct and inevitable result of the suppression, 

 from any cause whatsoever, of a considerable portion of the sup- 

 ply of water for the leaves. 



Considerable careful judgment umy at times have to be used 

 when making cuts of this nature, and occasionally it may be 

 wise to remove one or more healthy limbs, or perhaps to strip the 

 foliage partially from a branch situated just above a place where 

 much sapwood has been removed. This aaIII at least tend to pre- 

 vent wilting, Aviiich if excessive, may result in the subsequent 

 death of the branch. 



(3). Preservation of exposed wood from decay. 



If exposed surfaces of wood are left with no protective cover- 

 ing they soon become weathered, dried, checked, and easily in- 

 fected with fungi, causing decay of the wood. In the chestnut. 



