[composthappens]

Hi everyone,

can i make a fleece fence around my carrots to stop carrot fly? how high does it have to be please?

many thanks.

[sarajane]

Probably about 20 inches high.  We have made a frame and stapled thick clear plastic to it and for extra protection some mesh goes on the top.  This lets the rain in and for the last 3 years have been carrot fly free  -  the first time in 30 years.

Fleece is ok to use but I find a couple of strong winds (we put it around our sweetcorn earlier in the year,) and it soon rips. 

[Patty Pan]

I grew carrots for the first time this year. They were sown sucessionally in a couple of old bath tubs and alas, the dreaded carrot fly found them despite me sowing very thinly and not weeding or disturbing the leaves at all I will have to make some enviromesh covers for next year.

Does the carrot fly larvae overwinter in the soil? If I sow carrots in the baths again next year are they likely to emerge from the soil and attack my carrots - trapped inside by the protection covers?! 

If so will I need to change the soil - it would be a pain if so as I bought a few bags of sand which was mixed in with the riddled soil in each bath tub, or is there anything else I can do to be rid of them?

[Janeymiddlewife]

I'm afraid the larvae do overwinter
see this link http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=485

Mine were badly affected this year, I'll try resistafly next year as I'm not very handy at rigging up barriers, good luck!

[Gandan57]

Likewise the two tubs I grew carrots in were victims of the dreaded fly, even though I had mesh on the one on the right. 

[Patty Pan]

Thanks Janey, looks like I'm watering nemotodes in then as that will be cheaper than replacing the soil and sand...   
Gandan - I understand we would need a very fine mesh like Enviromesh to stop the pesky carrot fly as they are quite tiny 

[Mr B]

I covered mine with debrie mesh this year, no sign of any of the fly at all, last year was total devistation.

[NASH]

I covered mine with debrie mesh this year, no sign of any of the fly at all, last year was total devistation.

I did this too





And I am picking nice carrots like these

[Patty Pan]

Right then, water in the nemotodes, use Resistafly carrot seed and cover with debris netting, sorted, fingers crossed we have edible carrots then next year! 

[Salmo]

I did not know you could get nematodes that devour carrot fly. Has anyone used them and are they any good?

Since I posted this I have done some research. Several respected companies (Haddods, Suttons, T&M) market Nemasys which claims to control several important pests including carrot fly, cabbage root fly and onion fly. Also controls ants, caterpillars and sawfly.

The drawback is that it is expensive and needs applying every 2 weeks. 3 months control costs around £27.That will cover from mid-April to Mid-July. One presumes that carrot fly will need protection until September so say £50 for the season. It covers 60 sq metres.

If we can avoid buying enviromesh and netting for cabbage whites it could be worth it.

Does anyone have experience of using this?

[JayG]

A useful article HERE about carrot fly prevention, although no mention of nematodes.

This suggests that you could get away with re-using the soil if you sow later carrots next year because any pupae should have hatched and flown away by, say late June (turning the soil over a couple of times in winter should also help by encouraging their predators.)
(That's the theory, anyway; don't quote me!) 

Another point I found useful was the advice to bury the edges of the enviromesh 5cm beneath the soil to make sure the blighters don't just crawl in. Despite pegging my netting down very carefully this year I didn't actually bury it and I've found the odd carrot does have the fly, and I daresay its pals are now trapped under the mesh!   
(Burying the edges would make weeding even more of a chore, but worth bearing in mind I suppose.)

[MyAchingBack]

I have been reading that to prevent the invasion of carrot fly it’s best to grow carrots amongst onions. Does this work?

[DD.]

Forget it, the only way to be sure is a physical barrier.

[MyAchingBack]

Looks like I’m going to have to invest in a fleece, although I would rather lay it over the crop and peg it.

[Thephoenix572]

Is it best in tubs or in the ground. They seem hard to grow, does sticking near onions help at all