CABBAGE ROOT FLIES IN NORWAY; DIAPAUSE AND CHEMICAL CONTROL

Delia radicum /L/ and D. floralis /Bouché/ occur throughout the country cruciferous crops are grown.
D. radicum is a bivoltine species.
It terminates diapause during the winter and overwintered pupae have about the same thermal requirement for hatching independent of geographic area.
In the univoltine D. floralis this thermal requirement is very different in populations from different geographic areas.

Satisfactory control of the cabbage root flies in swedes was achieved by granular application in the seed furrow, and as band applications at transplant or 4 weeks later.
Insecticides tested were chlorfenvinphos and carbosulfane, at rates 1.25 and 2.5 kg a.i. per ha.
In transplanted cabbage plants raised in pots, preplant treatments with chlorfenvinphos granules or emulsion were less effective while precision spraying at egglaying was more effective than granules at transplant or in the middle of June.

International Symposium on Diptera Pests in Vegetable Crops

T. Rygg

https://doi.org/10.17660/ActaHortic.1988.219.13