Vine Weevil

I have a number of pots on my roof terrace. I have been repotting some of them today and notice in my Acer that there are lots of vine weevil grubs!!! Now i am worried they have been in there from late summer onwards, will the tree have died? What should I do to get rid of them. Please help

 

http://www.gardenadvice.co.uk/howto/pests/weaval-vine/

see the above link

I like the predators myself, might seem odd buying bugs to kill bugs...but the predators only live on the weevils not plant material so once the weevils are gone the bugs die off too, its an option if you don't like using chemicals

 

Don't nematodes need a certain temperature to work? If so, its quite cold outside at the moment. Would a pesticide be better? The Acer has buds on it, and its branches are still green so I hoping that the tree is still ok. My entire 'garden' is all in containers, are there any plants I shouldn't treat with insecticide to get rid of vine weevils.

 

I get my preditors from 'Defenders' and they do say 40deg f soil temp for vine weevil control.
Chemical wise you could try 'Provado' but be careful, I killed all my tuberous begonias with it two years ago.
Its best to apply the preditor late summer to catch the weevil before the temp. drops too low.

 

Thanks for the advice.