Three prospective agents instead of one? Cryptic diversity of the biological control agent Psylliodes chalcomera
The flea beetle, Psylliodes chalcomera, was previously permitted as a biological control agent of Carduus nutans (musk thistle) in the USA. However, during subsequent exploration for prospective biological control agents of Centaurea solstitialis (yellow starthistle), we observed individuals attacking this plant in southern Russia. We also observed this insect on Onopordum spp. (Scotch thistle), which raised the question whether this beetle is polyphagous, or whether it is comprised of biotypes, host races or cryptic species that are specialized on different host plants.