Landscape Structure and Biological Control in Agroecosystems
Carsten Thies,
*
Teja Tscharntke
Biological pest control has primarily relied on local
improvements in populations of natural enemies, but landscape structure may also be important. This is shown here with experiments at different
spatial scales using the rape pollen beetle (Meligethes aeneus), an important pest on oilseed rape (Brassica
napus). The presence of old field margin strips along rape fields
was associated with increased mortality of pollen beetles resulting
from parasitism and adjacent, large, old fallow habitats had an even
greater effect. In structurally complex landscapes, parasitism was
higher and crop damage was lower than in simple landscapes with a high
percentage of agricultural use.
Department of Agroecology, University of Goettingen, Waldweg 26, D-37073 Goettingen, Germany.
*
To whom correspondence should be addressed. E-mail:
c.thies{at}uaoe.gwdg.de