How selective are biological controls? Evaluating the potential for nontarget herbivory by Mecinus janthinus Germar [Coleoptera: Curculionidae], a biological control agent for Dalmatian (Linaria dalmatica L. P. Mill.) and yellow toadflax (Linaria vulgaris

摘要

Invasions by introduced organisms are thought to have profound negative affects on biodiversity and ecosystem health and function. The continued expansion of two invasive plants, Linaria dalmatica and Linaria vulgaris, into natural areas throughout North America merits further investigation into the use of biological control agents. Introduced Linaria spp. have the potential to displace native plants, as well as alter ecosystems in which they inhabit. The most promising biocontrol agent currently available is Mecinus janthinus, a stem-boring weevil shown to stimulate significant declines in Linaria spp. populations. As with many biological control agents, concerns regarding nontarget effects have likely slowed the use of Mecinus janthinus for controlling invasive Linaria spp. This study employed three components to evaluate host specificity of Mecinus janthinus: greenhouse and field experiments of possible nontarget host acceptance, and release site observations of potential nontarget use where this weevil has established. Plant host use of Mecinus janthinus in the field following open release of the biocontrol was also assessed in this study. (Abstract shortened by UMI.)