ABSTRACT 



Silvicultural operations often alter the forest environment to 

 provide conditions suitable for the development of forest pests. 

 In this study, weevils [ Magdalis gentilis LeC. (Coleoptera: 

 Curculionidae)] were attracted to thinned stands of lodgepole 

 pine, Pinus contorta var. latifolia Engelm. , in west-central 

 Montana. Adult weevils fed on current-year needles of crop 

 trees, often resulting in loss of 75 to 100 percent of the foliage. 

 Weevils did not appear to feed on, or breed in, the slash, nor 

 were they found in unthinned stands. Although not considered to 

 be serious, weevil damage can be reduced, or perhaps elimi- 

 nated by not thinning lodgepole pine stands before late July or 

 mid-August. With an increase in the acreages of forest planta- 

 tions and naturally regenerated areas in the northern Rocky 

 Mountains, it can be expected that problems involved with insect 

 pests of young trees will be experienced more frequently. 



