Colonisation of first-year maize fields by western corn rootworm (Diabrotica virgifera virgiferaLeConte) from adjacent infested maize fields

Abstract

The larvae of Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) are largely restricted to the roots of maize as food source, and their feeding damage can cause yield losses. The adults are active flyers in search for pollen sources or for new maize fields to colonise. The D. v. virgifera colonisation of first-year maize fields from adjacent continuous maize fields was studied in a 20 km2 intensive agricultural area in South-Western Hungary between 2008 and 2010. Using non-baited yellow sticky traps the infestation levels of adult D. v. virgifera were compared between six first-year maize fields and seven to 12 adjacent continuous maize fields during a seven week period in July and August in each year. The infestation in the continuous maize fields accounted for more than 60% of the variation in the adult D. v. virgifera captures in the adjacent first-year maize fields indicating that adjacent maize fields are the major source of dispersal into first-year maize and not, or to a lesser extent, the area-wide infestation levels. Therefore, estimating the risks of D. v. virgifera infestations in fields of a maize-rotating farmer can be supported by assessing the infestation levels in neighbouring continuous maize fields.