THE WHITE-PINE WEEVIL AND ITS RELATION TO 

 SECOND-GROWTH WHITE PINE' 



By S. a. Graham 



Assistant in Division of Economic Zoology, Minnesota State 

 Experiment Station 



The white-pine weevil, Pissodes strobi Peck, is one of the most 

 serious native pests of young white pine, Piniis strobus, and annually 

 deforms and otherwise injures a large percentage of the sapling pines 

 throughout its range. Because of its conspicuous injury, this insect was 

 early brought to the attention of entomologists and is frequently men- 

 tioned in entomological literature. Its life history, however, was never 

 accurately described until 1907, when Hopkins* described it fully. Up 

 to that time the white-pine weevil had frequently been confused with 

 other species of the same genus which had entirely different habits. 



The work of this weevil may easily be distinguished from that of any 

 other, since it is the only species in the range of the white pine that 

 works in the terminal shoots of the young trees, and it is found work- 

 ing nowhere else. In addition to white pine, the weevil attacks Norway 

 spruce very freely and has been reported frequently as feeding on 

 Scotch pine. 



A part of the data included in this article was collected in the vicinity 

 of Ithaca, New York, during 191 5 and 1916, and a part near Grande 

 and along the St. Croix River, in Minnesota, in the fall and spring of 

 1916-1917. 



The Adult Weevil 



The adult weevil is a small, somewhat elongated, rusty to dark brown, 

 snout beetle, varying in length from four to five mm. The proboscis 

 is slender and not longer than the thorax. The thorax is marked with 

 two distinct white dots and each elytra with a white blotch on the 

 posterior third. 



Point of Attack and Types of Injury 



The white-pine weevil seldom, if ever, actually kills a tree. It attacks 

 the terminal shoot or leader and the injury is usually confined to the 



* Published with the approval of the Director as Paper No. 83 of the Journal 

 Series of the Minnesota Agricultural Experiment Station. 



^ Hopkins : "The White-pine Weevil." Circular No. 90. U. S. Department of 

 Agriculture, Bureau of Entomology. 

 192 



