Search

The spatial influences of host and nonhost trees and shrubs on the colonization patterns of white pine weevil Pissodes strobi (Peck) were studied within a stand of planted interior hybrid spruce [Picea glauca (Moench) Voss X Picea engelmannii (Parry) ex Engeim.]. Planted spruce accounted for one third of all trees within the stand, whereas the remaining two thirds were comprised of early-successional nonhost vegetation, such as alder (Alnus spp.), paper birch (Betula papyrifera Marsh.), black cottonwood [Popular balsamifera ssp. trichocarpa (T. Ng.) Brayshaw], lodgepole pine [Pinus contorta (Dougl.) ex Loud. ], trembling aspen (Popular tremuloides Michx),willow (Salix spp.), and Canadian buffaloberry [Shepherdia canadensis (L.) Nutt.]. Unlike the spruce trees, nonhost vegetation in the stand was not uniformly distributed. Spatial point process models showed that Canadian buffaloberry, paper birch, black cottonwoood, and trembling aspen had negative associations with damage caused by the weevil, even though the density of the insects' hosts in these areas did not change. Moreover, knowing the locations of these nonhost trees provided as much, or more, inference about the locations of weevil-attacked trees as knowing the locations of suitable or preferred host trees (i.e., those larger in size). Nonhost volatiles, the alteration of soil composition, and overstory shade are discussed as potential explanatory factors for the patterns observed. New research avenues are suggested to determine whether nonhost vegetation in early successional stands might be an additional tool in the management of these insects in commercially important forests. [ABSTRACT FROM AUTHOR]

We conducted four behavioral choice tests in stands of mature lodgepole pine in British Columbia, from 1988 to 1991, to determine the dose-dependent responses of Orthotomicus latidens (LeConte) and Ips pini (Say) to their respective pheromones. Dose-dependent responses were exhibited by I. pini to (±)-ipsdienol and lanierone, with trap catches directly proportional to pheromone release rates. We found differences in sex ratio of I. pini in their responses to ipsdienol but not lanierone. There was no dose-dependent response exhibited by O. latidens to its pheromone, (±)-ipsenol, with or without the presence of the host kairomone, (-)-β-phellandrene. The bark beetle predator, Enoclerus lecontei (Wolcott), showed a dose-dependent response to lanierone. Thanasimus undatulus (Say) was attracted to ipsenol in a dose-dependent fashion only when traps were also baited with β-phellandrene. Neither T undatulus nor E. sphegeus (F.) exhibited dose-dependent responses to ipsdienol. [ABSTRACT FROM AUTHOR]

The synthetic pheromone (Z,Z)-3,13-oetadecadien-1-yl acetate was tested in two trap types and at different loads for trapping the Douglas-fir pitch moth, Synanthedon novaroensis (Henry Edwards) (Lepidoptera: Sesiidae), in a lodgepole pine, Pinus contorta Douglas ex Loudon variety latifolia Engelmann, provenance trial at the Prince George Tree Improvement Station, Prince George, British Columbia. This moth causes considerable problems in lodgepole pine seed orchards at this location. No significant differences in trap catches were found between wing traps and Unitraps in two experiments. There were no significant differences between catches in Unitraps baited with 50, 100, or 200 µg of the pheromone loaded on red rubber septa. In a second experiment, Unitraps baited with four rubber septa, each loaded with 200 µg for a total load of 800 µg, captured significantly more Douglas-fir pitch moths than those baited with one septum (200 µg) or two septa (400 µg) of the pheromone. All pheromone loads caught significantly more moths than unbaited control traps. Based on trap catches in these trap bioassays, and catches in monitoring traps in four lodgepole pine seed orchards, 1996 through 2000, the flight period of S. novaroensis in north central British Columbia normally starts in early June, and lasts for 4-7 wk. [ABSTRACT FROM AUTHOR]