THE LARGE LARCH SAW-FLY. 1 87 



In addition to the report summarised above, the Board for 

 Agriculture has also issued a leaflet which, owing to the 

 importance of the subject, we publish in full : — 



Memorandum on the Large Larch Saw-Fly. 



In recent years the larch plantations of Great Britain have 

 been visited by a pest which has already caused great losses in 

 certain places, and threatens to inflict serious injury on British 

 forestry. The large larch saw-fly is known to have done 

 much damage in Denmark about sixty years ago, and in more 

 recent times has devastated the larch forests of North America. 

 How long it has been present in Great Britain is not known, but 

 its presence was not officially confirmed till 1906, when it was 

 reported from Cumberland, It has since been found over a 

 large area in Wales, a wide district in the north of England, 

 and a very considerable area of the south of Scotland. It 

 probably exists in other parts of the United Kingdom. There 

 is reason to believe that the general attack is but slight, 

 but in the spots where the prevalence of the pest is greatest 

 many thousands of trees have been killed. Nor is it likely that 

 the plague will go no further. There are evident signs that it 

 has spread in recent years, and it is recorded that in the United 

 States and in Canada it did not stop till 50 to 100 per cent, of 

 the matured larch over vast areas was destroyed, with the loss 

 of many billions of feet of timber. The serious nature of this 

 prospect has led the Board to place the saw-fly among the 

 dangerous insects scheduled under the Destructive Insects and 

 Pests Order, the presence of which on any plantation must at 

 once be reported to the Board. They are also engaged on an 

 investigation of the extent to which it prevails in this country, in 

 the hope of discovering some preventive or remedial measures. 

 Every occupier of any premises on which the insect is found, is 

 bound therefore to report the discovery under a penalty of 

 £,10; but few cases have been reported, chiefly on account of 

 the inability of most persons engaged in forestry to identify the 

 pest, or recognise the symptoms of an attack. The saw-fly 

 remains in its larval state for only a few weeks of the year, and 

 for some part of that time it is very small and, consequently, 

 easily overlooked. The appearance of an attacked tree, how- 

 ever, is such that for a much longer period the characteristics 

 can be distinguished by an expert. In spite, however, of this 



