Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2008
Publication Date: 7/1/2008
Citation: Reding, M.E. 2008. Black Vine Weevil (Coleoptera: Curculionidae) Performance in Container- and Field-Grown Hosts. Journal of Entomological Science.43:300-310. Interpretive Summary: The black vine weevil (BVW) is an exotic beetle that is a serious pest of ornamental nursery crops. Damage is caused primarily by the larval stage, which feeds on the roots of plants often stunting or killing their hosts. Some plant species appear to be better hosts than others. However, there are gaps in our knowledge of how well BVW performs on different plant species. This information is important to help determine which plant species grown in nurseries are at the most risk of infestation by this pest. The current study shows that BVW larvae perform differently on plant species that are considered good hosts. Stonecrop (Sedum), Astilbe, yew (Taxus), and coral bells (Heuchera) are all considered very good hosts for BVW based on infestations in nurseries. However, we found that there were large differences among these species in the way BVW performed. Stonecrop and coral bells were much better host plants than yew or Astilbe when plants were grown in containers. These results indicate that growers should pay particular attention to stonecrop and coral bells when trying to determine whether or not they have an infestation of BVW. Furthermore, if left untreated, these two plant species may produce especially high populations of BVW in ornamental nurseries.
Technical Abstract: The black vine weevil (Otiorhynchus sulcatus F.) feeds on a wide variety of plant species and is a serious pest of ornamental nursery crops. The larval stage has a more restricted diet than the adults, but are more damaging because they feed on roots and often stunt or kill their hosts. Performance and establishment of larvae in various container- and field-grown nursery crops were examined. In trials on containerized plants, adult Black Vine Weevil (BVW) were caged with various combinations of known larval hosts. In one field trial, adult BVW were released and establishment of larvae among potential hosts was examined. Another field trial examined the influence of mulch on the occurrence of larvae. In the container trials, most larvae were found in Sedum and Heuchera versus Astilbe, Redbud, and Taxus. Larvae collected from Sedum weighed significantly more than those from Heuchera or Taxus. In the field, Sedum was a better host than hemlock or Rudbeckia. The presence of mulch around small field-grown Taxus plants did not increase the numbers of larvae compared to bare soil. Based on the numbers of larvae found in the different plant species, Sedum was the best host for larvae. The presence of aged pine bark or Taxus needle mulches did not influence the occurrence of black vine weevils in field plots of young Taxus. Data from monitoring adults suggests they either emigrated from the Taxus plots within several weeks of emergence, although suitable hosts were present, or there was high mortality.