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My runner beans are covered in blackfly, never had this problem to this extent before. What should I do? There are a few ladybirds and larvae but obviously not enough. I've cut off leaves that are covered in them but they're just multiplying and the ants aren't helping, they're keeping the vile things alive. help!


  • Pete.8Pete.8 Posts: 10,928
    Use a hose to jet-spray them off - if you're allowed to.
    Some years mine get them and it works for me. Eventually the ladybird larva cavalry turn up and do their job.
    I've had no aphids at all this year and not single bean either :)

    Billericay - Essex

    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • cornellycornelly Posts: 970
    Put some diluted washing up liquid in a spray bottle and give a good spray, always clears ours, may have to do it a few times but well worth the effort.
  • maggie-1maggie-1 Posts: 97
    Thanks both, I've tried the washing up liquid a few times but no luck so far and I don't want to harm the ladybirds. I've also used my (gloved) fingers to pull them off, and used a hose but there are so many I feel that I'm losing the battle. I need an army to get rid of this lot.
  • DovefromaboveDovefromabove Posts: 86,078
    edited August 2022
    I had a similar problem a few weeks ago. More black flies  than I’ve ever had before on the runners. I counted three ladybirds on the beans so  I crossed my fingers and did nothing … and very soon ladybird larvae, wasps and hoverflies etc had dealt with almost all of them. I didn’t even try hosing them off, but I did keep the beans fed and very well watered so they could outgrow any damage, which they have done. We’ve had an amazing crop and the freezer is already full!

    Fingers crossed it’ll be the same for you 🤞 

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • PlashingPlashing Posts: 328
    I had a this year aphids on my dwarf beans for the first time the ladybirds, wasps have just about cleared them, at present I haven't any on my runner beans but I have hardly any beans yet they are a few beginning to set so I will keep my fingers crossed.
  • nick615nick615 Posts: 1,459
    maggie-1  boil rhubarb leaves, drain off the liquid, allow to cool, fill a household spray bottle and apply to the affected area.  Keep left over liquid for refills.  As a precaution, because Rhubarb leaves are actually poisonous to humans, it'll be as well to wash beans thoroughly before eating (not that I've ever heard of anyone suffering from it).
  • maggie-1maggie-1 Posts: 97
    Thanks for all the suggestions, we went away for a few days when it was really hot so maybe the fact that they didn't get watered was a big factor plus the ants love dry soil. Lesson learnt, I knew I could rely on you all, so much knowledge and experience available. Thank You.
  • WhiterotWhiterot Posts: 39
    I had mine picked and in the freezer 4 weeks ago. If you set late you will always get blackfly and will struggle to get rid of it. I pinch the tops out and this year out of 40 odd plants I got blackfly on one. We are not that fond of broad beans my wife just uses the inner green bean in salads and stews of all description.
  • DovefromaboveDovefromabove Posts: 86,078
    @Whiterot the question is about runner beans, not broad beans. 

    I sow broad beans in October and harvest in May. 

    Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.

  • WhiterotWhiterot Posts: 39
    Sorry about that it's an age thing I have broad beans on the brain. I haven't got blackfly on the runners or French beans but it's the worst crop that I have ever had.
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