Monday 6 August 2012

Cabbage Root Fly

This pest is the bane of my life! I seem to be unable to defeat it. Last year it nearly destroyed all of my Winter brassicas, and this year I did everything I could to prevent it, but it seems I have failed again...

This is how I can tell. Here is a healthy Broccoli plant - foliage bright and turgid (i.e. it is "perky" and stands up firmly):

Whereas this plant's foliage is dull lifeless and flaccid (i.e. it is floppy):

This means that its roots have been attacked and it is no longer able to get moisture up into its leaves. It will most likely die.

And here are the culprits - a cluster of white maggots at the base of a PSB plant -  the larvae of the Cabbage Root Fly.

So, the brassicas collars that are supposed to provide a physical barrier to stop the fly laying its eggs near the plant stem didn't work. Nor did the application of a double dose of Nemasys Grow Your Own nematodes, administered exactly in accordance with the supplier's instructions. I am, as they say, "gutted".

Worst of all perhaps is the fact that the photo above, showing the maggots, is taken of the base of one of my reserve plants, grown specially to replace any casualties in the main batch of plants! So far, two of my six precious PSB plants are showing signs of attack.

My immediate action (after the initial shock) has been to put a squirt of the only bug-spray I have in my shed around the base of each of my plants. It is not one that mentions being able to kill Cabbage Root Fly larvae - but then which one is??? Maybe it will work, maybe not. All I can do is wait and hope. And keep the plants well watered so that they are not put under undue stress.

On second thoughts, I think maybe I'll also sow another batch of PSB seeds. I know it's late, but they might just come on in time...


  1. Sorry to see that the cabbage root flies have gotten to your plants. I don't believe I have ever had those before. Maybe because I have to plant all my cabbage in the fall and they grow through the winter and we don't have bug problems in the winter. They sure catch up in the summer though.

  2. Try a soap solution. It seems to disrupt insects PH and kills them right quick! Shouldn't hurt the plant. Worth a try anyway....

  3. Little blighters!
    I was going to suggest a solution of washing up liquid too. My Grandmother used to use it on all of her plants with great success...but I'm not sure whether it would work on Cabbage Root Fly larvae. It may be worth trying!
    It's got two chances hasn't it?
    Good luck ;D

  4. Oh how sad. I've tried those barrier methods to stop the root flies (which we call root maggots here), but have had little luck with it. I hope your other plants make it.

  5. Oh dear, poor you, poor PSB. I feel your pain, I had a similar situation with carrot fly. Maybe try washing up liquid with garlic in, I use that on any critters I find and it seems to work. I hope you recover or if you plant extra that they make it!

  6. Am sorry to hear that the collars didn't work, they seemed a brilliant solution. Still, maybe more of your plants might have succumbed had they not been there. We're currently being kept up nights worrying about late blight hitting the tomatoes. Oh, the challenges of gardening...

  7. Shame about the cabbage root fly. Sometimes creatures win the battle unfortunately.

  8. Oh how disappointing, those are some disgusting little pests.

  9. To control cabbage root fly try a strip of kitchen tin foil 1"wide wrap round base of plant at soil level.


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