Understanding the host finding behavior of a biological weed control candidate specialist as a contribution to pre‐release risk assessments

Pre-release host range assessments of weed biocontrol agent (BCA) candidates typically rely on no-choice and choice feeding, oviposition, development tests. However, these tests may exclude potentially environmentally safe BCA from consideration if they develop nontarget plant species in that would not colonize the field because behavioral barriers during selection. Here, we examined responses Ceutorhynchus rusticus Gyllenhal (Coleoptera: Curculionidae) to olfactory visual cues nine native North American two Eurasian confamilial invasive mustard dyer's woad, Isatis tinctoria L. (Brassicaceae). In bioassays with olfactory, visual, combined one vs. purified air and/or empty arms (control treatments), weevils responded attraction all offered I. but showed no preference for most relative control treatments. The weevil also faster when compared species. or those tinctoria, C. preferred over (olfactory cues: eight 11, 11 out species). results suggest mainly uses rather than alone early stages finding. Additionally, findings finding, prefers its species, reducing risks post-release attack field. Assessing multimodal can advance our understanding candidates' discrimination facilitate accurate interpretation conventional feeding data pre-release environmental safety assessments.