Vine Weevil Grubs

Loxley

Hello forkers, I hope you are all keeping safe and well. I have just removed a rhododendron from a large pot (to give to my sister as a gift) and found the roots infested with vine weevil. How thorough do I need to be in clearing up the soil? Will the grubs die now their source of food has been removed?

Regarding the main plant, can the grubs be killed by drowning them - placing the rootball in a bucket of water for several days?

wild edges

I've washed soil off to totally bare roots on some plants and still found weevil grubs tucked up inside cavities. They'll tunnel up inside fleshy roots and can be missed. Spread the soil out on a tarp or something and the birds should pick the grubs out for you but don't rely on them just starving as they might have stored up enough energy to pupate already. They won't drown either. I've tried dropping them in a glass of water and they still live for days.

Loxley

Oh dear. Sounds like I probably shouldn't be passing this plant on to my sis!

Cate 32

Morning I usually try and hand pick them into a plant saucer and leave for thrushes and blackbirds .  They love the extra protein and it’s ultimate recycling.  Then I dunk the plant in water for 24 hrs before replanting in new compost. You have to make sure they haven’t buried right up into the root crown .  Have a go very satisfying.  They are one of the only creatures I do kill.  

owd potter

Are all plants susceptible to VW infestation?
Found some under a sedum that I moved a couple weeks back
Prolly easier to ask which plants are not I imagine.

wild edges

No they seem to prefer plants with soft, fleshy roots that I imagine have active root growth in late winter and spring. Sedums are a favourite in my garden along with saxifrage, strawberry and, to a lesser extent, primulas.

barry island

I had a heuchera plant in a pot infested with vine weevil grubs, I cleared all of the soil off and left the stems in a bowel of water for a week this drowned all of the grubs which had burrowed into the roots, heuchera are hardy plant though so don't know if this sort of harsh treatment would suit other plants.

Loxley

I may as well give it a go. I'll need a big bucket though!

jeanbee

I am emptying some pots to pot up again and found vine weevil grubs  in the compost. It is a wheelbarrow load of compost. Can I put in the compost bin or will the grubs survive. I don’t want to re-use the compost 

Fairygirl

You could spread the compost out thinly in borders @jeanbee. The birds will pick off the grubs. You can do a bit at a time.
Or - spread it on a tarpaulin or similar, or even just on a big piece of cardboard etc. Again, you can do a bit at a time if you don't have room. The birds will take them.

The compost is fine to use afterwards as a mulch, or you can put it in your compost bin. 

madpenguin

I emptied out a huge pot the other day into the wheelbarrow and spent the whole satisfying afternoon sifting the soil with a fine sieve squishing grubs (200+) when I found them.
The sifted soil was scattered over the lawn so any grubs I missed would be found by birds.
Even though I treated all my pots last year with Provado they still keep turning up.
Also in various sizes from tiny to when they have 'wings' before turning to adults so just wondering if the mild winter has meant the adults have kept breeding?