Responsiveness of the broad bean weevil, Bruchus rufimanus, to Vicia faba genotypes

Abstract

AbstractThe broad bean weevil, Bruchus rufimanus Boh. (Coleoptera: Chrysomelidae), also called bruchid beetle, is a major pest of Vicia faba L. (Fabaceae) given that larvae develop inside the seeds causing direct quality losses in agricultural products. Recurrent chemical applications are inappropriate because they represent a serious threat to pollinators in general. In addition, biological control approaches that have been attempted so far showed limited effectiveness, which makes studies of methods to control bruchid populations extremely important. Breeding resistant cultivars is the most adequate approach to achieve efficient levels of pest resistance and promote sustainable agriculture. To explore the mechanisms underlying bruchid resistance, we explored B. rufimanus behavior at different life stages and preference in plant feeding, oviposition, and larval survival into adulthood on a range of susceptible and resistant broad bean cultivars (genotypes), both in greenhouse experiments and in the field. Our greenhouse results showed that females, compared to males, prefer flowers from some genotypes over others, although the choices made did not correspond with egg‐laying preference. Egg‐laying preference was also affected by cultivars. This attraction for egg‐laying was associated with the number of seeds per pod produced by the genotypes. In the field flowering date influenced bruchid infestation. Also the survival of larvae into adulthood was greater in certain genotypes over others. The results of our study lay the groundwork for further analyses to finely dissect V. faba resistance towards bruchids and pave the way for the development of methods to predict potential resistant genotypes in research and breeding programs.