FILMCOATING OF CAULIFLOWER SEED (BRASSICA-OLERACEA L VAR BOTRYTIS L) WITH INSECTICIDES TO CONTROL THE CABBAGE ROOT FLY (DELIA-RADICUM)

To assess the protection against cabbage root fly larvae achieved in cauliflower crops by filmcoating the seed with insecticide, six field experiments were carried out between 1990 and 1991. Various dosages of insecticides were tested at four widely separated locations in The Netherlands with high and moderate population densities of the cabbage root fly. The plants were raised in 'loose-filled cells' and peat 'blocks', or as peg plants. The efficacy of formulations of isofenphos, chlorpyrifos and fonofos, at two and three dosages of seed filmcoating, were compared with a conventional post-planting treatment. Filmcoating with fonofos was less effective in controlling cabbage root fly larvae than the post-planting treatment. Chlorpyrifos at 28.8 g a.i. kg(-1) seed and isofenphos at 30 g a.i. kg(-1) seed consistently gave as good control as a post-planting treatment of each plant.