Evaluation of Cyphocleonus trisulcatus (Coleoptera: Curculionidae) as a potential biological control agent for Leucanthemum vulgare in North America

Abstract

Leucanthemum vulgare, a perennial forb native to Eurasia, has become invasive in several other parts of the world. Since there is a lack of methods suitable for sustainable management of this plant across invaded landscapes, a biological control project has been initiated in North America and Australia. We evaluated the potential of the root‐feeding weevil Cyphocleonus trisulcatus as a biological control agent for L. vulgare in North America by investigating its impact on L. vulgare and studying its larval host range under no‐choice, multiple‐choice cage and open‐field conditions. Our impact experiment revealed that larval feeding by C. trisulcatus can severely damage and even kill plants. No‐choice tests conducted with 41 non‐target species showed that C. trisulcatus can develop on five closely related species. In a multiple‐choice cage test established with three of these species, the medicinal plant Matricaria chamomilla and the native North American M. occidentalis were also attacked, but to a lower degree than L. vulgare. An open‐field test conducted with four varieties of the ornamental Shasta daisy (Leucanthemum × superbum and L. × maximum) revealed similar attack on Shasta daisy as on L. vulgare. Due to the popularity of Shasta daisies, we suggest that C. trisulcatus, despite its potential to suppress L. vulgare populations, is not a suitable biological control agent for North America. However, C. trisulcatus may still be a potential biological control agent for L. vulgare in regions where Shasta daisy is less popular, such as Australia. Further host‐range tests with species native to Australia as well as with additional species important for the horticultural industry in Australia are currently under way.

Host Range and Impact of Dichrorampha aeratana, the First Potential Biological Control Agent for Leucanthemum vulgare in North America and Australia

“…This is in contrast to similar studies with other potential biological control agents. For example, in an open-field test with the root-feeding weevil Cyphocleonus trisulcatus , another potential biological control agent for L. vulgare , herbivory on L. vulgare and Shasta daisy by the weevil decreased with increasing distance (of up to 10 m) from the release point [ 15 ]. In addition, in a post-release open-field study with the root-feeding weevil Mogulones crucifer (Pallas), a biological control agent of Cynoglossum officinale L. (Boraginaceae), it was found that herbivory by the agent on both the target and a non-target species, Hackelia micrantha (Eastw.)…”

“…However, the popularity of the closely related horticultural plant Shasta daisy Leucanthemum × superbum (Bergmans ex J. Ingram) Kent (sometimes also referred to as L. maximum (Ramond) DC.) in North America makes this more challenging [ 15 ]. Shasta daisy is a highly polyploid hybrid of L .…”

“…Microplontus campestris , T. neesii , and D. stolidum were subsequently dropped from the list of potential agents owing to a lack of impact on seed output or host specificity, while studies with most of the other species are still ongoing. Work on C. trisulcatus for North America was stopped as pre-release open-field studies showed that attack on Shasta daisy was similar as on L. vulgare , but this species is still considered as a potential biological control agent for Australia [ 15 ].…”