Topic: Carrot fly

[mysticmog]

Having just lost my entire crop of carrots to the dreaded carrot fly, I was wondering if anyone had any cunning plan to prevent this...I had a 2ft barrier around them made of fleece, but I guess it didnt work...

Also, any idea why my carrot seedlings keep disappearing?  Would it  birds?

[tim]

Sad. The barrier was there from sowing?
Whatever - just lay the fleece across the lot & you'll never have a problem. Sowing to harvest. = Tim

[mysticmog]

Ah, the snowdrift method...my entire plot is gonna look like a winter wonderland...ah well, s'not supposed to be pretty, it's supposed to be edible :-)

Ta Tim

[sandersj89]

I personally think the 2 foot barrier/wall method is a waste of time. The theory says that the flies cannot get over it.

In reality I think they can and do, even if they are simply blown higher by any wind. The proof is my fathers veg garden. This is a walled garden, 12 foot walls on all 4 sides and one door that is kept shut 99% of the time. To walk through the door into the veg garden means walking 30 foot down a side path with a 5 foot wall on one side, then another gate.

If carrot fly cannot get higher than 2 foot he should be fine but he has to fleece his carrots.........

As Tim says, cover them over with fleeze. I use wire hoops to support the fleece but that is strictly not needed.

HTH
Jerry

[tim]

You mean like this, Moggie? = Tim

[GardnerJ]

is that what you really have to do? thats good because i thought of doing it but wasn't sure! Do you have to keep it like that for carrots from sowing to harvest tim?

Jemma

[tim]

Yes - for everything. So leave plenty of gussets. But drew the line, this year, at covering the perpetual caulis - grew to 40" x 40"!! = Tim

A small carrot sample.

[Jill]

Have you got a cheap supplier of fleece you can recommend  then, Tim?

[Jesse]

I have never used fleece before so this may sound silly for those who have, does it allow rain through or would I need to water more regularly if using fleece?

[tim]

Jill -yes - NA Kay - 01946 692134 - 12p/ft in a 50mx3.2m roll. Or others

Jesse - yes - but not as freely as mesh. It sags down, but never seems to harm the plants. = Tim

[sandersj89]

Jill -yes - NA Kay - 01946 692134 - 12p/ft in a 50mx3.2m roll. Or others

 It sags down, but never seems to harm the plants. = Tim

Agree with Kays as a supply. Very good service. Their on line listing is awful though so I rquest a hard copy which is better to work with.

Fleece is fine with regards to rain working through it. If you do frequently lift the fleece to weed or check progress it can damage the carrot leaves but this has little or no effect on the yield.

Jerry

[Jill]

Thanks again Tim!  Kays seem a lot cheaper than the garden centre where in desperation I paid £6 for a 10mx1.2m roll last autumn.  Stupid me.

See what you mean about their website, Jerry  :).

What would I do without A4A and you guys? ;D

[tim]

Silly me - AGAIN!

 12p SQ/M - NOT per foot!! = Tim

[Hugh_Jones]

A bit late in the day, I`m afraid, but as one who has experimented in just about every possible way with carrots and carrot fly I just had to put in my twopennyworth.

As tim says, you should simply drape the fleece over the carrot bed immediately after sowing - leaving plenty of slack at the edges - and the crop will simply lift the fleece as it grows.  You can both water and feed through the fleece without doing any damage. Leave it on until harvesting.

However the disadvantages with fleece are: (a) that you cannot properly see what is going on underneath it, (b) that it does create a more moist environment, which in some circumstances greatly encourages the growth of moss on the soil surface, and provides a better habitat for slugs, and (c) that it doesn`t last more than 2 or 3 seasons.  

Consequently, after some experimentation I now use fleece for the extra warmth to germinate the seed, but when I thin out the seedlings I immediate switch over from fleece to fine grade horticultural mesh.  Whilst being just as effective a barrier to carrot fly, this does allow a better air circulation around the crop and you can see what is happening underneath.  The only disadvantage of mesh is that it costs more, but my oldest  sheet of mesh has now been in use for 11 seasons, has survived an equal number of trips through the washing machine, and is still in as good condition (barring a bit of discolouration) as when I bought it.

[Roy Bham UK]

I just looked Carrot Fly up in an old garden book and they recommend scattering granules of bromophos or diazon along the rows, due to the age of the book could these now be banned chemicals? ???

Roy (still learning) ::)

[Hugh_Jones]

Yes, along with Whizzed Naphthalene Flake, DDT, Aldrin, Dieldrin and all the other environmentally unfriendly remedies so often advocated in old gardening books.

[john_miller]

And my two cents worth: prior to these products (either of them) being released onto the market the manufacturers did side by side comparisons with control plantings of certain crops. In every case yields increased with the crops under protection  compared to the control plantings. The biggest gain was in potatoes, at 195% of the control crop. These increased yields would be due mostly to increased warmth and because the moisture loss due to transpiration is substantially reduced, allowing greater utilisation of water by the plant in tissue manufacture. Alternatively the greater retained heat will allow a desired crop size to be reached more quickly. Pesticide management would have been to used as necessary to maximise yield in both plots but was also reduced on the plants under these products.
One way of avoiding crop leaf damage that has been used is to sow a taller plant than the crop (grasses for instance) some time prior to planting (obviously this requires some planning). Done properly the grass grows up and supports the mesh or fleece above the crop leaves.

[tim]

Interesting stuff, John.
Hugh - I wholly agree with you on mesh. And you can see cabbage whites through it - should any get in! It's just that it's expensive for newcomers, & you would never cut up a piece of edge-bonded mesh to suit?
And I don't think that you can get the 50' lengths that we need?

I do find that fleece can last 4-5 years - cut to size if it gets holes in it. = Tim