Vine weevils

Discussion in 'Pests, Diseases and Cures' started by groundbeetle, Jun 25, 2021.

  1. groundbeetle

    groundbeetle Gardener

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    I just found vine weevils in my patio, which were kindly identified by posters on this forum. I have never had vine weevils before, only noticed them in about the past month, and I think they could have arrived on an Auricula primrose I bought in a pot in April. It was expensive and never flowered properly, but I was hoping it would flower next spring. There isn't anything else in the patio it could be, most of my plants in pots were grown from seed, and have been there a long time.

    Is there any point in using Nemasys nematodes right now? Will it kill eggs, or only the larvae? Should I just wait until autumn when the larvae start eating my plant roots?

    Do Nemasys nematodes kill anything else, good or bad, besides vine weevils?

    I am not happy with what I have read about the chemical solution, as people are saying it kills anything that eats the plant, including bees that eat the nectar and pollen, and greenfly that eat the plant, so presumably ladybird and lacewing larvae that eat the greenfly that eat the plant.....
     

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    Last edited: Jun 25, 2021
  2. Upsydaisy

    Upsydaisy Total Gardener

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    They can come from anywhere, flying past and seeing your plants in pots they spotted an ideal environment for breeding. They are particularly partial to plants in pots.
    I don't get them that often, so don't use any treatments ,when I see a sickly looking plant I check their root system and if weevil grubs are found I pick them all off and feed them to the birds . I then thoroughly clean the plant removing all the soil and checking all its roots , cutting away any really damaged bits. The plant is then left overnight with its roots submerged in water and a final recheck is done the next day before replanting in fresh soil/ compost.
    Works for me :biggrin:.
    You could also go out at night with a torch and catch the blighters in action as the adults are nocturnal....and squish!!
     
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    • ricky101

      ricky101 Total Gardener

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      Hi,

      If not already viewed, see the info here about Nematodes -
      Nemasys Vine Weevil Killer

      BBC - Gardening - Advice: Pest and disease identifier

      The adults often go after particular plants like pot grown Strawberries and Fuchsias, but they will go almost anywhere in pots or the ground, though seems they prefer lighter peaty soils .

      Apart from the methods already mentioned in that other post about them, you could try putting a layer of gravel on your pots to try and stop them laying their eggs in the soil.

      Also as the adults feed mainly at night , so go out at dark with a torch etc, if distrubed, the Weevil is said to freeze and drop off the plant and play dead, so you may be able to catch a good few of them that way.

      The plants can usually withstand the adults taking a few bites out of them, its the grubs that do the real damage eating the roots away, so you typically find plants dying off in spring when they try to put out fresh growth, but with no roots just flop over.

      We have had them before and at the time you feel you will never get rid of them, but thankfully had little trouble from them since, so do not go overboard with pesticides etc.

      Things like Provado will kill most soil living creatures that may feed on the weevil grubs, plus if you read how it affect those creatures, some kind of paralysis of their mouthparts, it puts us off using it, not knowing if it could affect us as you nearly always get some on your skin from the watering can or even worse a spray !! so use rubber gloves , mask and goggles if you must use it .
       
    • ricky101

      ricky101 Total Gardener

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      Hi @Upsydaisy ,

      Seems they cannot fly, other than by BA and potted plants. :)

      Some more facts and a lovely video on them here.

      Black vine weevil
       
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      • groundbeetle

        groundbeetle Gardener

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        I just tried washing and separating the roots of the Auriculum primula, and found it is totally infested with small yellow spheres that pop. I am not sure if anything in the pot is worth saving?

        And as somebody wrote, they don't fly, and my back patio has high walls, and I bought this Auricula from a reputable well-known nursery in April, and never had vine weevils before.

        I feel so upset....
         

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        • ricky101

          ricky101 Total Gardener

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          It happens to us all at some time, regardless of the supplier you purchased from.

          There looks plenty of heathly roots, so we would continue to remove all the soil and eggs, then repot into some clean compost and with a bit of TLC they should recover, though the top growth may flop for a while after such a distrubance, you might want to consider cutting some of its bigger leaves back as well.

          Don't give up ! :smile:
           
        • groundbeetle

          groundbeetle Gardener

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          I just washed all the soil and eggs off the roots and repotted in clean compost mixed with perlite.

          I need to research its lifecycle, but at this stage I am guessing that the Auriculum arrived at the end of April with larvae in its roots, which turned into the adults that I have been finding all over my patio. And the eggs that I found the roots to be infested with must be new eggs that those adult laid recently? All the larvae must have turned into adults now, so there is no point using Nemasys nematodes right now, maybe in autumn when eggs start to turn into larvae? And also going outside after dark with a torch or just the patio light, and picking off the adults. I will probably have to apply nematodes in autumn to all the plant pots in my patio? (And hope that the nematodes don't harm good larvae like ladybirds, hoverfly and lacewings).

          And thanks to the people who identified the vine weevil adults, I would not have known what they were or gone looking in the Auriculum's rootball for eggs, or know that I have to apply some nematodes in the autumn and try to pick off as many adults at night as I can. The first thing I would have known was when my beautiful plants just keel over and die. My patio is full of all kinds of things in pots that I have been growing for a long time.
           
          Last edited: Jun 25, 2021
        • NigelJ

          NigelJ Total Gardener

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          @groundbeetle The small yellow spheres could be slow release fertiliser pellets often used by commercial nurseries.
          The nematodes don't, as far as I know, harm the beneficial insects.
           
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          • pete

            pete Growing a bit of this and a bit of that....

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            I think you need to check out the life cycle of a vine weevil.
            The eggs would not still be there on a plant you bought April, I dont think, in April you would have had grubs.
            The Auricular does appear to have adult vine weevil attack, but I'm not sure all of it is.

            Its not really worth going OTT over it, pests are around all the time and we live with them.
             
          • Upsydaisy

            Upsydaisy Total Gardener

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            Thanks @ricky101 .....you learn something new everyday.!!
             
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