5 o6 FAMILY SCOLYTIDAE 



The following are extracts from a note relating to an insect attack 

 published in the Indian Forester (vol. xiv, April 1888) under the title 

 " Note on Insect Ravages in Pine Forests," by G. G. M. The insect I 

 identify as this Polygraphus. G. G. M. wrote: 



The study and prevention of disease in forest trees is of such great importance, and so 

 intimately connected with the prosperity of the forests, that a few notes on a disease in the 

 form of a pest of insects which has done extensive injury in many of the pine forests under my 

 charge in the Sutlej Valley (Bashahr) may be of interest. 



The pest to which my notes refer made its appearance during the summer of 1882 and 

 spread at an alarming rate over large areas. Young vigorous trees invariably shook it off, 

 but less hardy ones were either rapidly killed or after lingering for some time died out. The 

 leaves of infested pines turned an unhealthy yellowish colour, and the branches dried and 

 curled up into claws, giving a most wretched appearance. At the end of the rains the disease 

 abated, and to all seeming disappeared, and for four years the forests were free from its 

 ravages. But in June 1887 it returned, and this time attacked both the Finns excelsa and 

 /'inns gerardiana. In July I noticed that the leaves of the affected trees were beginning to 

 change colour, and that the insect had prepared for first operations the ends of branches, and 

 that it had tunnelled out between the bark and sapwood longitudinal galleries which, on close 

 inspection, I found to contain larvae and weevils. I continued to observe these during the 

 rains. . . . ; later on, when no more larvae remained, the perfect insect abandoned the 

 tender shoots for larger branches, through which it worked holes as far as the heart-wood and 

 in the direction of the axis of the stem. Branches thus attacked were tatooed all over and did 

 not survive long. This destructive insect .... is one-tenth inch in length, with dull 

 brown-coloured elytra, and its larva is a small white grub of the same length .... Its 

 duration of activity is three months, which is as long as the rains last, for at the end of 

 September its depredations ceased and in October I had difficulty in finding any beetles alive. 

 But doubtless they leave behind in dead wood ample deposits of eggs, which are hatched on 

 some favourable atmospheric change occurring. 



These careful observations by G. G. M., an officer who held charge of 

 these forests for a number of years, are of great importance, since they 

 conclusively prove the serious nature of the damage P. major is capable of 

 doing to young growth of the species it infests. 



The measures to be taken to combat the attack of the blue-pine borer 



are similar to those laid down for the deodar bark- 

 Protection and , j _,,,.. , , 

 Remedies borer (vide p. 572). The blue-pine insect, however, only 



attacks poles and saplings, and will not be found to 



infest poles whose bark has attained a thickness which results in an outer 

 layer or covering of old dead bark being present on the tree. 



For egg-laying purposes the insect requires soft sappy bark. Conse- 

 quently small poles may be felled as "trap" trees, but they must be green. 

 The fact that they dry fairly quickly does not appear to inconvenience the 

 insect once the larvae have become half to two-thirds grown. 



In fact, in areas where this beetle exists (and my observations would 

 seem to show that it is invariably present wherever the blue pine is present 

 on a tract, even though the tree may be scarce), an inspection of green felled 

 blue-pine saplings or poles or green branch-wood will almost invariably 

 eal the fact that they are full of this insect either egg-laying or (depend- 

 ing upon the time of inspection) full of larvae and pupae or maturing beetles. 



