Dolatia coriaria (Kraatz) (Coleoptera: Staphylinidae) as a Pest of Laboratory and Greenhouse Colonies of the Western Corn Rootworm (Coleoptera: Chrysomelidae)

Abstract

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, (Coleoptera: Chrysomelidae) is a serious pest of corn (Zea mays L.) in north-central North America and parts of Europe. Females lay their eggs in the soil during mid to late summer. The following spring, the eggs hatch and larvae feed on the subterranean roots of corn. Larvae are the most damaging life stage and can cause extensive yield loss to corn (Gray and Steffey, 1998). The subterranean nature of the larvae makes control and biological studies difficult. Aspects of WCR biology are often evaluated using populations adapted to laboratory conditions. Insects from these colonies are then utilized in laboratory, greenhouse, and field experiments. We report here the infestation of WCR colonies under laboratory and greenhouse conditions by the rove beetle, Dolatia coriaria (Kraatz), (Coleoptera: Staphylinidae) with suggestions for minimizing infestations. Our research group routinely rears a number of WCR colonies (Meihls et al., 2008). From shortly after oviposition until 2nd instar, many of our colonies are reared in small containers (15 cm 3 10 cm, 708 ml, The Glad Products Company, Oakland, CA) filled with corn seedlings and a medium of 2:1 autoclaved soil and ProMix TM (Premier Horticulture Inc., Quakertown, PA). This first rearing container is typically maintained in growth chambers under 14:10 [L:D] photoperiod and 25uC. When WCR larvae are approximately second instar, the contents are transferred into larger containers (33 cm 3 19 cm, 5.7 liters, Sterilite Corporation, Townsend, MA) and placed in greenhouse bays. Following emergence, adults of each colony are confined in 30 3 30 3 30 cm plastic and mesh containers (MegaView Science Co., Taichung Taiwan) in a room with 14:10 [L:D] photoperiod at 25uC. Adults and larvae of D. coriaria were first detected infesting greenhouse WCR rearing containers, but quickly spread to all rearing areas. Observance of D. coriaria corresponded with a decline in WCR larval populations and subsequent adult emergence.