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Allium leaf miner


I have an allotment in Nottingham and this year my crop, and many others on the allotment site, have had our crops of onions and leeks devastated by a fly of some kind.

I have investigated the cause and on checking the RHS website it appears to be Allium leaf miner as the photograph on the site exactly matches our leeks and onions. The pupae can be found in the body of the leek where I understand that if it were leek moths that were causing the problem the pupea would overwinter in the soil.

My questions are is there any treatment to prevent the crop devastation in future years other than covering the crop? Are there any companion plants that may confuse the fly and prevent them from laying their eggs? Or should we just stop growing alliums?

Any advice on this would be greatly appreciated.


  • I had the same problem on my leeks in January earlier this year (in Leics).  No sign of them on this year's crop (yet) but I suspect the mild winter we had last year was as much to blame as anything and I'm hoping for a few good hard frosts to kill the miners as well as a host of other pests.  Environmesh should work but I'll be taking a season off from growing leeks if this crop is also affected.  I also wonder if the increasing number of decorative alliums being grown nowadays is providing enough extra host plants to cause an explosion in numbers of this pest.  Probably a combination of climate change and that.

    A trowel in the hand is worth a thousand lost under a bush.
  • I had this last year. I bought some environmesh, as Bob suggested and it worked a treat. No nasties of any sort. It also protected the cabbages because they were in a nearby bed- the E'mesh was so large, it covered everything nearby!

  • WhiterotWhiterot Posts: 43

    It devastated all the onions,  shallots  and spring onions on our allotment site last year. It also reduced the garlic crop which meant that I had to replace all my cloves rather than saving some but it did not bother the leeks.

    I bought environmesh , which I use on my carrots each year and made a tunnel with canes and blue piping. Went to the site this morning and noticed that all other allotment holders onions have been infected but mine seem ok. I also grow onions from seed but have delayed taking them to the allotment until last week where I set 3 rows of red not under the net as there was no space and again these are ok. My garlic and shallots has been under a similar net since I set them and that is ok. Despite me explaining how to combat the problem no other allotment holders have taken any precautions hence another year of no onions. The moto is cover them or grow onions from seed and delay transplanting until late May

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