Vine weevil attack - advice needed

[SJANSELL]

Help - after never having problems before, I now have vine weevils chomping roots both in my pots and flower beds. Unearthed a huge number after a heuchera came out in my hands yesterday. I squidged as many as possible, but suspect they are well entrenched. I did have some drench stuff, but am trying to be more organic. Do nematodes work? I'd like to know from people who have tried them. Should I be putting them in now? We used them on slugs last year, with some success, although it's a bit of a losing battle in my pretty untidy wildlife garden, especially as my husband loves hostas. Sarah

[artdemole]

gardenadvice.co.uk may help

[SJANSELL]

Thanks, haven't seen that site before. I have done some more research on various sites and the solutions aren't easy.

The nematodes need warm soil (over 4 or 5 degrees) but weevils can start their evil work at lower temps. So maybe delay applying them until spring gets going but you may lose some plants.

The drench can be effective but one site said that the chemical in it might be implicated in colony collapse disorder in honeybees. The drench is taken up by the plants, so mustn't be used on edible crops.

You can use foliar sprays on adults in the summer, but I guess with the same possible problem for bees?

There used to be a compost with the chemical impregnated in it, but it's not marketed now.

Centipedes are natural enemies. Weevils especially like primulas, sedum, fuschias, impatiens and cyclamen - which explains the fate of my impatiens a couple of years ago!

I'd still like to hear from anyone who has tried nematodes, as they seem the most wildlife friendly solution? Sarah

[Geoff F]

You may find this advice sheet from Gardening Which useful Pests and diseases M-Z - Gardening factsheets - Your garden - Which? Advice

I've almost eradicated them by simply not growing any of their favourite food plants. They are quite specific and won't touch primroses although they love primulas. I also found that hardy fuchsias escape damage while the tender 'one season wonders' were avidly chomped.

To start with, I was squashing them, until I discovered a better method; now I place the grubs on a birdtable where they quickly get eaten

[Susie]

I've not had them in the garden before, only in pots. In that instance I disposed to the plant (which was decimated anyway and not worth having. it was a grape vine) and the soil too. I understand that they don't like wet soil so perhaps regularly watering the garden would help until the soil warms up enough to use nematodes would be an idea.

[Cotham Marble]

Originally Posted by SJANSELL

Help - after never having problems before, I now have vine weevils chomping roots both in my pots and flower beds. Unearthed a huge number after a heuchera came out in my hands yesterday. I squidged as many as possible, but suspect they are well entrenched. I did have some drench stuff, but am trying to be more organic. Do nematodes work? I'd like to know from people who have tried them. Should I be putting them in now? We used them on slugs last year, with some success, although it's a bit of a losing battle in my pretty untidy wildlife garden, especially as my husband loves hostas. Sarah

Commiserations Sarah - vine weevil can make a gardener's life miserable. The only chemical treatments that show any sign of working need to be applied in in the Autumn while the grubs are developing. These chemical treatments are not species specific and and will kill a wide range of soil based invertebrates, and are not allowed to be used on food crops !

My experience is that vine weevil is now endemic and the only sound way of dealing with it is to avoid plants which support it, particularly when growing in containers and raised beds. There's a list of susceptible plants here: Vine Weevil - Plants susceptible to Vine Weevil - Debbys Garden Links - UK Gardening Directory . Nematodes are useful for treating contained areas - greenhouse, pots and raised beds etc but unless substantial quantities are used, unlikely to be effective on large open areas. There's also the problem of whether or not neighbouring gardens are affected, if they are thenthe adults will simply repopulate the following year even if the nematodes have an impact in your garden.

The good news is that there are plenty of native and/or otherwise wildlife friendly plants and it is not too difficult to adapt to the presenceof the 'evil weevil'. From my own non-scientific observation, I'd say that the greatest problem with Vine Weevil infestation comes from attempting to grow acid soil loving plants in areas of calcareous soil, though of course that's not the only cause of the weevil's spread. I had to give up on an ambition to pot grow a wide range of Mint species because they were so loved by the vile beast. Anyway I've swapped a garden with Vine Weevil for one with Honey Fungus, so maybe I can have Mint collection now, if not all the woody plants I had hoped to grow.

CM

[SJANSELL]

Thank you very much for all the useful advice and links. We do grow quite a few of the vulnerable plants, so I think I need to compile a list of alternatives. There is now a more weevil resistant strawberry apparently (Florence).

And as a cautionary tale - I had some unused drench stuff in the shed and thought I'd just use it on just a few of my favourite but vulnerable container plants and then use nematodes (although I think they work best in late summer/early autumn). Without thinking (I am pretty brain dead at the mo due to medication) I tipped some in one of my blueberry containers. After running around like a headless chicken cursing for a few minutes I dug out the top few centimetres of soil (luckily I hadn't put much in) and poured gallons of rainwater through it. Probably I shouldn't risk eating them, although my husband did point out that we only ever eat a small amount at a time. We do have two other blueberries so maybe I'll stick to those.

So - no more drench - organic all the way I think!! Just ordered my nematodes for slugs and weevils as well as some of this shocka matting to see if it deters the slugs.

I think that learning to put the right plants for the right place and conditions etc is probably the hardest lesson I've learned over the last couple of years! Sarah

[sumbody]

The year before last I used the nematodes for the vine weevils that I knew would be in my strawberry pots and fuchsias for the first time (autumn).

I must say there was a marked improvement in the strawberry pots - only found a couple as opposed to 20+ as normal. In the smaller fuchsia pots that had overwintered in the greenhouse there were none.

Last autumn I didn't get any nematode treatment and both my strawberries and fuchsias have suffered quite badly this spring. I have also found them in my mint pots - and today found lots in a large pot containing chives.

Of course they don't go to waste - my robins love them as do most other birds.

I will definitely be using the nematodes again this Autumn - especially on edibles, but these are all in pots.

[tom00_uk]

in the ground they are not to much of an issue, but in pots they will soon kill a plant, best bet is to dispose of the plant, on the nursery any root balls suspected of being infected went on the fire

there is a compost you can get thats got a chemical in that stops them, but of course it will also affect other inverts