THE LARCH CANKER. 



5 



of the disease, and that well-managed and well-thinned mixed 

 plantations afford the least chance for the propagation of the 

 canker ; but at the same time it should be remembered that as 

 this is a specific disease, if the trees are free from the canker, and 

 no neighbouring trees producing the spores, the chance of infec- 

 tion is reduced to a minimum. 



In the case of this fungoidal attack, as in all others of a like 

 nature, when it is observed care should at once be taken to 

 destroy effectually — and the only effectual method is to burn 

 with fire — all portions attacked, so that the spread of the 

 disease is stopped, and it will be found better to sacrifice the life 

 of a few trees rather than to expose the rest of a plantation to 

 the risk of infection. 



With regard to the treatment of individual trees, with a view 

 to sparing their lives and saving the timber, the surgical method 

 of excising the diseased parts, and protecting the necessarily 

 exposed surf aces by means of grafting wax or any other innocuous 

 substance, is worthy of the attention of foresters. This method 

 of cutting out the bark and cambium at the diseased spot was 

 recommended in my paper dealing more exactly than I can at 

 the present time do with the life-history of the fungus, pub- 

 lished in the Eoyal Agricultural Society's Journal, 1891. 

 Among others who were interested and good enough to give this 

 suggested treatment a trial, Lord Moreton, then President of 

 the Royal Agricultural Society, having some diseased trees, 

 had the diseased portions cut out, taking care to leave none 

 of the discoloured infected cortex or cambium behind, and then 

 the wound so caused was protected by means of grafting wax and 

 covered over with a piece of sacking. Some time after this 

 treatment it was found on removing the bandage that the tree 

 had been able to cover over the wound with new cambium and 

 cortex, and to a great extent recover its original shape, and 

 there is no doubt that if this treatment is effectually carried out 

 it should lead to the cure of the tree. However, the discussion 

 of the disease, with the treatments which practical men may 

 devise to combat it, will no doubt lead to the discovery of 

 methods of a practical, and at the same time effectual, nature of 

 dealing with the disease, and Larch growers all over Britain will 

 have reason to be grateful to the Royal Horticultural Society if 

 they are able through their deliberations to help the forester in 

 fighting this the most deadly enemy of an almost indispensable tree. 



