Abstract
Native Cirsium species play an important role in landscapes across North America. Hadroplontus litura (F.) (formerly Ceutorhynchus litura), the stem-mining weevil and biological control agent of Canada thistle [Cirsium arvense (L.) Scop.] can complete its life cycle on five Cirsium species native to the upper Midwest. Although these five Cirsium species are within the fundamental host range of H. litura, as determined by host-range tests, we wanted to explore whether phenological differences among Cirsium species help define the field ecological host range of H. litura. The objective of this study was to determine the phenology of Cirsium species native to the upper Midwest in relation to C. arvense and H. litura. Our goal was to explore whether shoots of native Cirsium species could escape H. litura shoot oviposition in spring due to delayed shoot emergence relative to C. arvense. Soil cumulative growing degree days (GDD) were a superior predictor of shoot emergence for perennial Cirsium species or initiation of leaves in biennial Cirsium species, with a 2.4 times larger effect on time to emergence relative to air GDD. All native Cirsium species initiated new leaves or shoots before C. arvense shoot emergence, even when native Cirsium species growth was delayed in the spring. In turn, C. arvense shoots emerged approximately 1 to 3 wk before female H. litura began to lay eggs. As such, all native Cirsium plants had shoots available for H. litura oviposition. There was no phenological separation between native Cirsium and C. arvense shoot emergence or initiation that would render native Cirsium species safe from H. litura attack. Based on the phenology of shoot emergence or initiation in the spring, all tested Cirsium species native to the upper Midwest would be within the ecological host range of H. litura.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 47-55 |
| Number of pages | 9 |
| Journal | Invasive Plant Science and Management |
| Volume | 16 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 23 2023 |
Bibliographical note
Funding Information:We would like to acknowledge the following groups and individuals for providing funding, Cirsium seed, expertise, and labor for this project: Chicago Botanic Garden: Kayri Havens Minnesota State Climate Office: Peter Boulay Minnesota Department of Natural Resources: Ross Hier, Burnham Wildlife Management Area; Welby Smith, Dan Wovcha, Laura Van Riper Prairie Legacy Inc: Kay Kottas The Nature Conservancy, Ordway Prairie: Matt Graeve, Toni Aguilar University of Minnesota: Mary Marek-Spartz, Brad Kinkaid, and Ryan Mentz, with additional help from Parker Sheaffer, Hugo Dos Santos Oliveira, Aryane Batista, Kylie Rich and Lewis Sheaffer US Fish and Wildlife Service: Gregg Knutsen, Craig Mowry, and Jordon Young Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative‐Citizen Commission on Minnesota Resources (LCCMR). No conflicts of interest have been declared.
Publisher Copyright:
© 2023 The Author(s). Published by Cambridge University Press on behalf of the Weed Science Society of America.
Keywords
- Biological control
- Canada thistle
- native thistles
- phenology
