A new host record of Cotesia vestalis (Haliday) and its ecological significance

Abstract

The parasitic wasp Cotesia vestalis (Haliday) is known as a primary parasitoid of the diamondback moth Plutella xylostella (L.), an important pest of cruciferous crops. From June to September 2024, we collected Leuroperna sera (Meyrick) caterpillars from the wild cruciferous plant Rorippa indica (L.). Parasitoids that emerged from the collected caterpillars were reared over generations and identified as Cotesia vestalis. This is a new host record of Cotesia vestalis. Furthermore, no P. xylostella individuals were collected from the surveyed R. indica plants. These findings suggest that in the warm regions of Japan, L. sera plays an important role as an alternative host for C. vestalis wasps during the summer months when cruciferous crops and P. xylostella populations decline.