Topic: carrot fly

[aquilegia]

How big are carrot flies? (ie - what's the smallest gap one could get through?)

I seem to remember that they are fairly low flying - but how low? You see I was thinking if I grow some carrots in pots and put them high enough the carrot fly won't reach them, they won't need any more protection???

[Mrs Ava]

I think they are teeny tiny - that is a scientific term you know.  And that whole flying thing is a bit wishy washy (more science talk) as they are so tiny, they get blown about on the breeze, kinda like spiders do, so can get up quite high.  Have to say, I have grown carrots okay in my garden, in pots and on the old family lottie and never had carrot fly probs.  I think if you don't disturb them too much, leave thinning and stuff til the end of the day, they are less likely to be a problem.

Yours, scientific wonder!  ;D

[teresa]

seem to remember if you grow onions either spring or chives between the rows of carrots this confuses the carrot fly.
Otherwise sow the seeds thinly so no thinning is required. See if I can practice it this year on my plot?

[aquilegia]

hmm - teeny tiny is definitely going to get through the gaps in the fence! I think that will keep out anything up to the size of smallish (by insect standards anyway!)

Teresa - yep leeks, garlic and chives will all (hopefully - depending on germination) be growing round the carrots, but I like to cover all bases! (first year of carrots!) But sowing thinly - that's something I've never managed to achieve (I'm a bit-more-for-luck sower!)

[tim]

- fleece will protect - mesh won't. = Tim

[Mrs Ava]

http://www.hdra.org.uk/organicgardening/gh_cfly.htm

Don't know if you have seen this aqui, but might be helpful.  ;D

[ina]

I read that they fly no higher than 80 cm off the ground but the wind thing posted before makes sense. Also, they don't lay eggs after 4 pm so any thouching of the plants should be done after that time.

Mine always go in early in the season (put the seeds in last week) and except the occasional affected carrot I have not had problems in the past. I read that the seedlings and young plants can stand frost up to minus 8 C. They must have anti-freeze in them hahaha.

[cleo]

fleece

Stephan

[teresa]

Ina
Do you cover yours with fleece?

[tim]

Lucky people - wish I could get mine in now - but 40deg min soil temp is a long way off in this neck of the woods! = Tim

[ina]

No Teresa, I never use fleece for anything.

[Hugh_Jones]

Tim, I noted your reply favouring fleece rather than mesh. For the last two seasons I have been running a test of fleece versus mesh, and have found absolutely no difference between the two for protection against fly - the mesh worked as well as the fleece.

The only difference between the two, I found, was that fleece, particularly if laid on the bed 2 weeks before sowing, resulted in faster germination by several days, although the plants under mesh subsequently made better growth.  The optimum result was obtained by sowing under fleece and then changing to mesh as soon as the seedlings reached thinning out stage.

[tim]

I bow to your experience! = Tim


PS - And mesh is so much more substantial - and you can see through it!

[aquilegia]

ooh - lots of useful info! THanks all!

Hugh - that is interesting to know...

EJ - thanks for the link - very useful.

[Dunc_n_Tricia]

We got our lottie in April last year, and were told that nobody managed to grow carrots in normal beds 'cos of carrot root fly.

Everyone seemed to have raised boxes in which they grew their carrots. They could then ensure the best soil conditions, and were too high for the carrot fly.

Decided to have a go anyway, but planted one seed every 2" or so. One web site I read said that the flies only found the carrots by the smell of bruised thinnings - no thinnings, no smell.

The doom-sayers (they're all really nice friendly people really), said that we wouldn't get any worth eating. They ended up eating their words! We got some lovely big juicy carrots. When our site chairman (a Gent of generally good humour) saw them, he called me strange names, and generally seemed rather impressed.

This year, I'll try the same again. Different varieties this year, but will still sow at 2" intervals and not thin out. If your site is usually infected, i heartily recommend you try - it might just work!

Tricia  :-*

[Steve__C]

Hugh,

I assume you had carrot fly damage while doing your 'experiment'.

It would be interesting to grow carrots under three conditions - fleece, netting and nothing.

I suspect that, if you had no noticable difference between fleece and netting, then you would have no noticable difference between fleece and no protection.

[Hugh_Jones]

I`m sorry, Steve, but I`m afraid all your assumptions are completely wrong.  Let me say at the outset that I grow in an area where it is impossible to grow carrots without protection, and that attempts over many years using barriers of glass, polythene, wood etc, and interplanting with numerous `companion` plants all proved hopeless.  Carrots would grow, but before they reached any size would be eaten completely away below ground.  Then fleece was invented, followed by horticultural mesh. I have been using fleece for 12 years, and mesh for 10.  I have also conducted experiments over several years as to the so called `safe`periods, and established (to my own satisfaction at least) that in my garden exposure of carrots for any period of 14 consecutive days during the season April - end/September results in fly damage.

Growing under either fleece or mesh, there is no fly damage whatever, as long as the cover remains entire, and there was no fly damage before, during or after the change from fleece to mesh.

I must also add, at this stage, that I get large numbers of `bird sown` carrots (from the seed on the bird table) in my garden, and these are invariable ravaged by carrot fly.

The experiment was not to find out which gave the greater protection from fly - I already knew there is no difference in that respect - but to determine which provided the better growing conditions for carrots. I used 3 sections of bed, and sowed the same variety (Autumn King 2) in each section on the same morning. Sections 1 and 2 were covered with fleece, and section 3 with mesh. The carrots were thinned as soon as the tops were big enough to handle with thumb and forefinger and this was 6 days earlier in sections 1 & 2 than in section 3.  After thinning section 1 was re-covered with fleece, but section 2 was covered with mesh, the mesh also being replaced on section 3.

At that stage the carrots in sections 1 & 2 were distinctly ahead of those in section 3.   However, by July it was clear that the plants in section 2 were the best, and had the best developed roots, very closely followed by section3, while those in section 1, although they had luxuriant top growth, lagged considerably behind in root production.  The other clearly noticeable result was that section 1 had considerably more top growth of weeds, as well as showing soil stagnation in the form of moss growth on the surface.

I accept that my experiment would not meet the criteria, either in duration or in mode of execution, of a horticultural research station, but the results have convinced me.

I trust that this answers your points.

[tim]

Hugh - mesh - I stand corrected - I was referring to 'standard' rather than 'fine', which protects against virtually every thing. Sorry. = Tim

[Hugh_Jones]

No need to apologise, tim. Indeed your posting helps to re-inforce my explanation to Steve, who apparently had not the faintest idea whatever what horticultural mesh is, and makes the rather inexplicable assumption that if there is no fly damage under mesh then there aren`t any flies anyway - somewhat akin to assuming that if you don`t get wet inside your house it can`t be raining outside.

[SueT]

You guys (Hugh & Tim) are so sexy when you get technical! ;D ;D ;D ;)