Biological control of purple loosestrife, Lythrum salicaria L. (Lythraceae) with Galerucella spp. (Coleoptera: chrysomelidae), dispersal, population change, overwintering ability and predation of the beetles, and impact on the plant in southern Manitoba wetland release sites

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Diehl, Jason K.
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A classical biological control program using two leaf-feeding chrysomelid beetles, one root-feeding weevil and two flower-weevils has been implemented in North America to limit further spread of Lythrum salicaria L. The first of four sections in this paper style thesis pertains to the dispersal and total egg estimates of Galerucella spp., including their impact on L. salicaria stem density and fruit production within four release sites in southern Manitoba during the 1995 and 1996 growing seasons. The fourth chapter includes a study determining the ability of caged adult Galerucella spp. to overwinter within release sites during the winter of 1995-96. In the summer of 1994, a survey of insects associated with purple loosestrife in southern Manitoba was conducted; the results of which appear in Chapter V. As a result of this survey, a potentially important predator of Galerucella spp. larvae was identified within release sites at Libau Marsh, MB. Results of field studies in cages to determine the effect of the predatory stinkbug, A. bracteatus, on the larvae of Galerucella spp. are presented in Chapter VI of this thesis. (Abstract shortened by UMI.)