53 



In all probability the disease is worst on closely planted estates, 

 where, necessarily, the bark renewal of tapped surfaces is poor since 

 the increase in girth is slow. 



On estates where the spacing of the trees is adequate to allow 

 for good growth and rapid renewal it is possible that the trees are 

 able to throw off. the disease. 



If the rainfall is unusually excessive the spacing factor would 

 obviously not have the same significance. 



Although pruning is not i-ecommended at all in the ordinary 

 course of events as I consider it necessary to provide all possible leaf 

 area and not to deprive the tree of any branch if it can be avoided, 

 it may be necessary to prune in oi'der to increase the distance 

 between soil and foliage to allow for access of light and air where 

 there are .serious outbreaks of the fungus. 



Water lying about on the surface soil would increase the 

 moisture content of the atmosphere about the level of the tapping 

 surface, preventing rapid drying and increasing the chances of 

 infection. Should such a condition exist remedial measures should 

 be adopted without delay. 



It is not easy to give any definite reliable information on the 

 treatment of the disease at the present time for the reason, as I have 

 stated above, that sufficient time has not passed to allow one to draw 

 any sound conclusions. 



When trees are badly affected it would seem that superficial 

 treatment with disinfectants would not check the disease as it could 

 readily spread in the wood behind the cortex and bark could be 

 re-infected at a lower or higher level. It would, therefore, be 

 necessary to cut out the affected bark and possibly the superficial 

 layers of wood — in any case all dead bark should be removed. 



The tapped surface of slightly affected trees may be painted 

 with a 50 per cent, solution of Jodelite (half Jodelite, half water) 

 or even a stronger solution or a 20 per cent, solution of brunolinum 

 twice a week for three weeks. 



It may be necessary later on to cut out the diseased bai'k but 

 such drastic measures should not be taken unless the other method 

 fails, as the resulting wound is a serious matter. 



In all cases tapping should cease on affected trees. I have not 

 seen any evidence to prove that the disease is cai'ried by the tapping 

 knife but it is quite possible that that may happen. To be on the 

 safe side it may perhaps be advisable to sterilize the tapping knives 

 and for tliis purpose to use a 5 per cent, solution of formalin which 

 should be carried by the tappers in receptacles of some kind large 

 enough to hold the knife. After each tree is tapped the knife 

 should be placed in the formalin solution. 



