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Nematodes

I have a dreadful infestation of vine weevil and my plants, both in pots and in the ground, are being ruined. When is the best time to dose with nematodes and where do you suggest I buy them?

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  • tessagardenbarmytessagardenbarmy York,North YorkshirePosts: 346
    I can't use nematodes as heavy clay soil too wet and cold (in a normal summer!).I use Provado once a year on my pots as I love heucheuras and they are very susceptible.
  • Joyce21Joyce21 Posts: 15,489
    Provado- March and September in my pots of heuchera.
    I've never had vine weevil problems with plants in the ground so don't know about nematodes.
    SW Scotland
  • DovefromaboveDovefromabove Central Norfolk UKPosts: 79,270
    I find nematodes very effective against vine weevils in this garden.

    About now is a good time to apply them ... the RHS website says

    "6. Vine weevil (Otiorhynchus sulcatus)

    CONTROL: The larvae of vine weevil feed on the roots of many plants, especially those being grown in pots or other containers. The grubs can be controlled by watering into the potting compost a suspension of the pathogenic nematode, Steinernema kraussei. For best results nematodes need to be used in a well-drained potting compost or light soil, which must be moist. Treatment in August to early September should control vine weevil grubs before they are large enough to cause serious damage.

    Steinernema kraussei will remain active at soil temperatures down to 5ºC (41ºF), so control can also be achieved later in the autumn to spring period, although late treatment may fail to prevent some damage occurring. A different species of nematode, Heterorhabditis megidis, is available from some suppliers, this requires soil temperatures of 12-20ºC (54-68ºF).  The nematodes Heterohabditis bacteriophora and H. downsei are also available for vine weevil grub control.

    A trap containing nematodes (Steinernema carpocapsae), is also available for controlling adult vine weevil. The traps should be placed on the ground below plants damaged by the weevils during the summer. The adults enter the trap during the day and are infected by the nematodes."


    I buy the nematodes online from whichever supplier is offering the best price.  You will need a watering can with a coarse rose to apply them.  


    Good luck  :)

    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh







  • plant pauperplant pauper Posts: 6,234
    The plants in the ground seem to survive 🤞 but in a very tatty state. A rhododendron and some bergenia ground cover about 200 feet apart are very bad because the wee skitters are everywhere.
    I've all but given up on heuchera in pots Joyce as they are like ambrosia to the grubs.  :(
    I now read that they like Laurel too and as I had planned a laurel hedge I'm starting to rethink that...again! They are a pest in the true sense of the word.
  • debs64debs64 West Midlands, on the edge of the Black Country Posts: 4,327
    I use the ones for slugs apply in May depending on weather and find them amazing. Wildlife friendly too unless you count slugs! 
  • I have got all my heucheras in pots this year- they seem to do so much better than in the ground for me... thanks for the advice, I will keep my eye on them.  Is it also a good time to use the nematodes for slugs? 
  • NewBoy2NewBoy2 BristolPosts: 1,808
    I have used Nematodes for the last 4 years on my allotment and they are very effective.

    I used to get say a 100 slugs but now only see 1 or 2.

    I get them from Marshalls on the interweb.

    I only do one session but they say its best to do two.......but they would

    Someone I grow with used to work at the local research station where they tested them and she confirms they work.
    Everyone is just trying to be Happy.....So lets help Them.
  • Can they be used for containers? e.g I have hostas in pots. 
  • plant pauperplant pauper Posts: 6,234
    Yes they can @gardeninglily1. The pack I was looking at gives coverage for both pots and open ground. I was looking at a large quantity as I'll have a fair bit to do but they have a shelf life so I'd better get my ducks in a row and be ready to do the whole lot in a short time. No faffing!  :)
  • NewBoy2NewBoy2 BristolPosts: 1,808
    Gardenlily.................If you read the instructions and find you only need say 10% of the 12 million you get you could give the rest to someone else so they can use them as they are worms that are basically asleep when in the fridge and only get active when they are watered in.
    Everyone is just trying to be Happy.....So lets help Them.
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