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Sadly we have black fly on some of our runner bean plants. We have sprayed them but, more interestingly, they are being eaten by what we thought were caterpillars. Having googled the problem, indications are that the little insects are more likely to be syrphid fly (Hover Fly) larvae. They are up to 1cm long, have legs and are black with yellow stripes running across their bodies.

Just wondered if anyone else has seen these and can confirm my thoughts?



  • BobTheGardenerBobTheGardener Posts: 11,391

    About half of all UK hoverfly larvae prey on aphids - they are very beneficial in the garden.  I have thousands at the moment in the garden and most of the aphids now seem to be gone.  It's a pity they don't appear earlier in the year but I suppose that's when ladybirds usually do the business (although I've seen very few of those in my garden this year.)

    A trowel in the hand is worth a thousand lost under a bush.
  • nutcutletnutcutlet Posts: 27,169

    Always check the ID of any insect or its larva and find out what it does before you kill it. There's a balance to nature which works very well until man and his poisons comes along

    In the sticks near Peterborough
  • gatehillgatehill Posts: 38

    Many thanks for your comments

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