Topic: Carrot FLy

[Mrs Ava]

Have asked before but no answer was forthcoming.  When is the risk of carrot fly damage over?

[tim]

With luck, we should be in the clear?

This is the first year we've had none in unprotected crops. In raised beds. So maybe there is some truth in flight height??

http://www.hdra.org.uk/factsheets/pc17.htm

[jennym]

The second generation are about and laying their eggs still here.
Funnily enough, mine, unprotected by fleece, haven't been attacked this year, (so far) but I am growing them on a different plot. This, to me, indicates that previously I've not helped matters by not clearing debris in which they over-winter in on the other plot.

[Icyberjunkie]

Other than planting some orange wall flowers to confuse them, and following advice to only thinning in the evening and remove all debris I have not specifically sprayed or anything.

As far as I know I have had no attacks so may have just been lucky.   Having said that I'm not aware of anyone on our lottie being attacked!!  We are near LIttlehampton in West Sussex.

[RSJK]

I remember reading some where that the carrot fly does not like the smell of creosote, and to hang some Hessian soaked in it between the rows to discourage them, have not try-ed it myself yet as anyone else?.
                                                                                                       :-\

[jennym]

Not tried creosote - don't think I like that idea! :)
However, I do interplant with spring onions, and also, when pulling any onions to use green, or young leeks etc, I have a pair of old scissors and I snip the onion foliage and let it fall where the carrots are. I think this helps to deter the fly a bit.

[Mrs Ava]

OKay, well last year I lost way over half of my carrots thanks to carrot fly and slugs, this year I have fleeced and have had perfect carrots!  The fleece is still insitu, but I would like to take it off to weed and edge.......me thinks I shall keep it on for another week or 2 if they are still about in some parts of the south. 

Thanks everyone!

[Dirkdigger]

According to my local expert Emma, they are active in September. Keep covered as much as you can.
Not lost any on my plot but some of the others have.
DD

[ChrisH]

Here are some items from  bbc.co.uk/gardening/

How do you control carrot flies?
Chris Beardshaw replies
 
Carrot flies pose a real problem for carrot growers, as they can kill seedlings and the small maggots eat into mature roots and cause them to rot. Telltale signs are reddish leaves that then wilt in warm weather and turn yellow. Unfortunately, no variety is resistant to this pest and no single control can be deemed to be completely successful. Several measures can be taken to try to prevent infestation. Grow your crop away from tall plants that would otherwise provide shelter for this pest. Sow seeds thinly to avoid the need for excessive thinning - carrot flies are attracted by the scent of bruised foliage, which inevitably occurs in the thinning process. If thinning is necessary, take care and destroy any thinnings. It is usually recommended that maincrop carrots be sown between April and June for lifting in September and October. However in areas where carrot fly is known to be a particular problem it is suggested that sowing is left until June and the crop harvested in August. Organic gardening guides recommend interplanting your carrot crop with an onion crop - it is thought that onions produce a natural chemical repellent to carrot fly.

What can I do to prevent carrot root fly attacking my carrots next year?

Bob Flowerdew replies
 
Carrot fly overwinters in the soil, so you must rotate your carrots. Grow them in a different piece of ground each year and don’t come back to the same place until at least three years have passed. Sow as early as possible to avoid attacks by getting the carrots bigger and tougher sooner. Sow thinly so you do not need to thin. Never touch the foliage unnecessarily as this releases the smell that attracts the fly, apparently from up to seven miles away. So if you touch or pull some carrots then take the foliage off and drop it off somewhere else in the garden to lure the fly away from the crop. Confuse the pest with a mix of onions and leeks among the carrots. Make a barrier at about hip height to stop the low-flying critters. Or even better, seal the crop under a fleece or fine net curtain from when you sow it until harvest.

and from the RHS encyclopedia of gardening, page 660

'Control: Enclose susceptible plants within a clear polythene fence at least 60cm (24in) high, or grow under horticultural fleece, to exclude the low-flying female fliers.'

Hope this helps
Chris

[Icyberjunkie]

Thats excellent Chris!   Thanks for taking the time to post it.

Iain

[Mrs Ava]

Here here!  Excellent piece.  Well, even though they need a weed, they will remain covered until all are harvested.  I am so chuffed with them after taking Sanders advice when sowing, then Tims and co with the fleece.  Have been pulling lovely long, strong strongly flavoured carrots as and when we need them.  That area will just have to stay scruffy a while longer!  Thanks everyone.

[redimp]

Everything I cover with fleece gets eaten by slugs and snails - just can't win.

[busy_lizzie]

I emptied a bag of compost in a metal dustbin this year and planted my carrot seeds in there.  Have picked quite a few and they are lovely, though just about five inches long, think because I didn't thin them out properly. I steam them gently and they taste so sweet. 

 I thought I would put the  carrot soil on the compost heap when I am finished and next year do the same thing in another location.  busy_lizzie

 

[Mrs Ava]

OOo, BL, they look glorious!  THe kids grew some in long pots and they were also slim, but oh so tasty!

[moonbells]

I've had decimated carrots for a few years until last, when I decided to make a wooden frame and cover it with enviromesh. Would have been perfect if the mesh had been wide enough and I hadn't had a foxcub go through the fleece I put over the gap! Then the flies got in... so last year's crop was better than before but not perfect.
2004: completed frames (L) and the fox damage (R)


So far this year, so good. Started them under plastic cloches in March,  took the mesh off the remains of the frame (which by then had been destroyed by the vandal attack at Christmas) and turned it into a Geoff Hamilton cloche, adding more rows every few weeks.  I've only got slug damage this year.

2005 (June):


I also found that fleece cloches are fragile and don't let rain through as well as enviromesh.

moonbells

[Roy Bham UK]

You don't need to cover them, leave the roof off and the rain will get in as long as the walls are approx 18" high as the fly can't fly that high, I fink? ???

Anyway using that method for my first year they grew lovely.

[moonbells]

Indeedy they can't fly very high. Unfortunately they don't make enviromesh in strips and so I have to have it over the top! (and as it's woven, if you cut it you end up with spaghetti nylon and no mesh  :( )

And as I mentioned, the local wildlife can break through fleece...  ::)  I have wondered about going to a jumblie and getting some old net curtains which are about the same as the mesh except cuttable but I'm always up the lottie when they're on :) :) :)

moonbells

[TEL]

Hi all
Just picked a few carrots & some of them have got carrot fly maggots in them.
What a bummer >:(

[TEL]

HI again
Is there a spray to kill these .

[jennym]

There is nothing listed on the pesticide register, so there's nothing legal in the UK for amateur use.
Commercially, products containing: pirimicarb or aldicarb or chlorpyrifos may well be in use for this pest. You would need to be licenced to use it.