Black vine weevil (coleoptera: curculionidae) performance in container- and field-grown hosts

Abstract

The black vine weevil (Otiorhynchus sulcatus F.) feeds on a variety of plant species and is a serious pest of ornamental nursery crops. The larval stage has a more restricted diet than the adult stage, but the larvae are more damaging because they feed on roots and often stunt or kill their hosts. Performance and establishment of larvae in various container- and fieldgrown nursery crops were examined. In trials on containerized plants, adult black vine weevil were caged with various combinations of known larval hosts. In these 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 one field trial, adult black vine weevils were released, and establishment of larvae among potential hosts was examined. In this trial, Sedum was a better host than hemlock or Rudbeckia. Based on the numbers of larvae found in the different plant species, Sedum was the best host for larvae. Another field trial examined the influence of mulch on the occurrence of larvae. The presence of mulch around small field-grown Taxus plants did not increase the numbers of larvae compared with bare soil. 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 suggest they either emigrated from these plots within several weeks of emergence, although suitable hosts were present, or there was high mortality.