Barbarea verna and Barbarea vulgaris as host plants for the pollen beetle (Meligethes aeneus)

Abstract

During the introduction of a new crop, it is important to study and select for resistance to pests to ensure preservation of possible natural protection in the plant material. One accession of Barbarea verna (Mill.) Asch. and one of Barbarea vulgaris R. Br. was exposed to female pollen beetles, Meligethes aeneus Fab. (Coleoptera: Nitidulidae) in a greenhouse experiment. The experiment was initiated to reveal the extent to which the plant material is accepted as a host plant to this important Brassicaceae pest. The two species, B. verna and B. vulgaris, were used for oviposition by 26% and 21% of the females, respectively. The amount of oviposition and feeding injury on either of the two species throughout the experiment did not indicate any difference in acceptance of the species by the pollen beetle. For both species a majority of the egg-laying females oviposited only once during the 5-day period and laid less than 3 eggs per clutch. The females present on the Barbarea spp. were not more disposed to accept the species as the days passed and the mean clutch size did not increase with time since previous oviposition. Females laying eggs used large and small buds of B. verna to the same extent for feeding. On B. vulgaris there was a tendency for more frequent use of large buds for feeding than small. Acceptance for oviposition by the pollen beetle on the two accessions of Barbarea is low in this experiment. Injury caused was limited to a level probably tolerated by the plant material without causing economic damage. As the oogenesis of the pollen beetle is reduced by exposure to low-quality host plants the potential natural protection would endure despite an increasing occurrence of the species.