Low altitude carrot fly?

One of the gurus on our site tells me that carrot fly cannot fly much above 12 to fifteen inches high! So if I place some kind of guard around my carrot plants the dreaded fly can't get at them!
Anyone else suscribe to this theory?

It could be that the flies home in on the smell of carrots, settle on the outside of the barrier, walk up and over the top. Once inside nice and sheltered and lots of lovely carrots. Carrot fly heaven.

some people grow carrots next to onions or plant out companion plants to confuse the flies

I'll be covering EVERYTHING that doesn't need insect pollination next year.

I don't mind losing the odd plant to a slug but the plagues of things round here destroy entire crops which just isn't fair.   

I first read your post as Low attitude carrot fly !!
I have been assured that there is none on our site ! Well no-one seems to use any sort of protection so I'll wait and see - haven't seen any signs yet, but it's waay too early.
Some folks swear by spraying with garlic water just before thinning to mask the smell - might help??

I first read your post as Low attitude carrot fly !!
I have been assured that there is none on our site ! Well no-one seems to use any sort of protection so I'll wait and see - haven't seen any signs yet, but it's waay too early.
Some folks swear by spraying with garlic water just before thinning to mask the smell - might help??

That's the way I shall go; one of the guys offered me something a bit stroger, but if I want to eat poison I'll use the supermarkets!

 haven't seen any signs yet, but it's waay too early- quote.

No its not. My two successful plants from my first sowing about 6" tall were found flopped over with grubs in the roots. The second sowing about 2" high seem to be untouched. They are all now covered top, sides and ends with fine netting.