Resistance of Western White Pine to White-Pine Weevil

Abstract Western white pine (Pinus monticola Douglas) is resistant to attack by the white pine weevil [Pissodes strobi (Peck)]. Adult weevils were caged on trees of eastern white pine (Pinus strobus L.) and western white pine (P. monticola); indices of attack were used to determine which stages of the life cycle of the weevil were affected by resistance mechanisms. Adult weevil mortality was negligible for both species; the numbers of feeding cavities on P. monticola were greater than on P. strobus. Numbers of adult emergence holes and leader mortality were similar for both species. The results suggest that resistance mechanisms of P. monticola either inhibit the weevils from traveling to the trees or induce them to leave.