40 MISC. PUBLICATION 273, U.S. DEPT. OF AGRICULTURE 



Western States there are several species that do similar damage; 

 though not yet of economic importance, they are almost sure to be 

 so when second-growth stands and plantations are more widely 

 established. 



Proper silvicultural methods offer the best solution of the weevil 

 problem. Where young trees are grown in dense stands, or under 

 the shade of other trees, weevil injury may be negligible. If in 

 handling young stands subject to weevil injury the shade of older 

 trees can be provided until the young trees reach 25 feet in height, 

 or if the young trees can be grown in dense stands until they have 

 passed the susceptible period, the damage should be lessened. In 

 plantations, where individual care can be given, some control can 

 be obtained by cutting off the infested stems in May and Septem- 

 ber and burning them or storing them in wire cages of a mesh 

 small enough to hold the beetles but large enough to allow the 

 parasites to escape. Weevil populations have been controlled at 

 the time of emergence and egg laying by airplane spraying with 

 DDT, applied at the rate of 1 pound of DDT per gallon of fuel oil 

 per acre. 



The Sitka spruce weevil (Pissodes sitchensis Hopk.) is the in- 

 sect most injurious to Sitka spruce reproduction in the Pacific 

 Northwest. The small weevils attack and kill or seriously injure 

 the terminal shoots of many young trees, causing a crook in the 

 trunk or a forked and worthless tree. Trees from 2 to 8 inches in 

 diameter and 5 to 25 feet high are most susceptible to attack. 

 In some plantations the Sitka spruce weevil has been so prevalent 

 that nearly all young trees have been weeviled. As a result, the 

 planting of Sitka spruce has been largely discontinued in Oregon 

 and Washington. The species is distributed throughout the range 

 of Sitka spruce. 



The adults are light to dark brown, oval-shaped beetles, about 

 % 6 inch long, with a prominent curved beak. Late in the spring 

 and early in the summer the adults feed on the tender bark of the 

 previous year's terminals and with their beaks make little cavities 

 in which eggs are laid. The young larvae, which are white, legless, 

 curled grubs, work down the stem, boring through the bark and 

 into the wood. Upon reaching maturity they form in the wood or 

 pith an oval cell lined with shredded wood fiber in which to pupate. 

 There appears to be only one generation a year, but some of the 

 insects transform in the fall of the year and others change and 

 emerge the following spring. The winter is passed in all stages 

 except the egg. Upon emergence the new adults do some feeding 

 on the fresh bark of the terminal shoots and make numerous small 

 feeding punctures, which later heal over with a bit of resin. No 

 effort has been made to control this species. 



Similar in habits and appearance to the above is the Engelmann 

 spruce weevil (Pissodes engelmanni Hopk.). It works in the ter- 

 minals of Engelmann spruce throughout this tree's range, in the 

 Rocky Mountain region and the Pacific Northwest. 



The lodgepole terminal weevil (Pissodes terminalis Hopk.) 

 (139) mines through the pith of lodgepole pine terminals (fig. 14) 

 and kills them down to the first whorl of branches. It is particu- 



