Biological performance of the white pine weevil in different host species and in two ecological regions of southern Quebec

Abstract

The performance of the white pine weevil (Pissodes strobi Peck) was studied on five different host species: Norway spruce (Picea abies (L.) Karst.), white spruce (Picea glauca (Moench) Voss), red spruce (Picea rubens Sarg.), jack pine (Pinus banksiana Lamb.), and eastern white pine (Pinus strobus L.). Attacked terminal leaders were collected prior to adult emergence, within two different ecological regions of Quebec, the Outaouais and Appalaches regions. According to their natural range, jack pine was studied only in the Outaouais region and red spruce only in the Appalaches one. Weevil performance did not differ between regions but differed among host species. The number of eggs laid per leader was greatest on jack pine, white pine, and Norway spruce (279, 219, and 218 eggs per leader, respectively). Adults emerging from white pine were the heaviest (0.0104 g). The number of adults per leader was greater on Norway spruce and white pine (34 and 23 adults, respectively), and survival tended to be greater on Norway spruce and white spruce leaders (18 and 15%, respectively). Norway spruce had the longest leaders, and jack pine had the thickest ones. Leader dimensions were correlated with all variables of weevil performance, except insect survival, but these characteristics explain only a small part of the variation in weevil performance. Norway spruce and white pine can be considered favourable hosts for rapid population buildup according to the high number of emerging adults per attacked leader.