7oo 



PARKS 





PLATE No. 256 



GALLERIES OF THE WESTERN PINE BEETLE 

 (DENDROCTONUS BREVICOMIS) 



Photograph by United States Bureau of Entomology. 



in the management of the 

 park. Too sudden changes, 

 even for the ultimate better- 

 ment of conditions, are often 

 devitalizing to trees. 



2. Dead, badly infested 

 and hopelessly weakened 

 trees should be removed 

 promptly and destroyed. 

 Often, and particularly in 

 the case of coniferous trees, 

 such trees serve not only as 

 breeding places for injurious 

 species, but attract and tend 

 to localize in damaging num- 

 bers primary and secondary 

 insect enemies. In the case 



of conifers the trees to be destroyed should be removed and burned, includ- 

 ing the stump, with the greatest possible rapidity. 



BORERS 



Most of the wood-boring insects are secondary in the nature of their 

 attack, infesting weakened trees or those that have been injured and the 

 wounds of which have not been treated. The borers of elm, maple, linden, 

 etc., are of this group, and measures tending to promote healthy, vigorous 

 growth and the protection of wounds will eliminate much of this type of 

 injury. 



Some borers are primary, however, such as the locust borer, the white 

 pine weevil and the shoot moths. Over these some advantage may be secured 

 by dense and mixed plantings during the early years of the tree's develop- 

 ment. Shade and dense growth are undoubtedly strong protective features 

 under such conditions. 



Treatment consists of the removal and destruction of the infested 

 material, and occasionally in the killing of the borers by running flexible 

 wires into their burrows or by injecting a little carbon disulphid into the 

 gallery openings with an oil can and then tightly plugging all the holes for 

 several days with grafting wax, putty, or some gas-proof material. The 

 wounds should then be opened, cleaned and painted. Carbon disulphid is 

 inflammable and poisonous and should be handled with care. 



