Judith in France wrote:
Bromophos is no longer available, so I am told, what do others do to
control it?

Judith

Plant marigolds (tagetes?) in between the rows to act as a natural
deterrent. Google "companion planting" for more info.

Another method is to sow carrots in a plot previously occupied by
onions/garlic whereby the residual roots will give off a scent to deter
carrot fly.