I would probably do all of the above. Spread the soil out for birds to pick through, use nematodes of which I have had some success, sift soil and have used provado on hostas I've replanted last year and on a large potted rhodo that I can in no way lift.
I have also lobbied my MP about the conversation that is currently taking place in parliament on the use of pesticides and the protection of bees. I acknowledge that global warming IS taking place and that my local fruit farm which IS organic has lost 30 % of its bee population over the winter. Without bees we cannot have a fruitful existance as huge crops depend on it for their and our very survival. I do agree that a single plant in every garden treated with pesticide has a alltogether large effect, but the pesticide industries have a much much bigger effect. Sort the big users out and nature will cope very well with the little users, is my humble opiniion, for what its worth.
There is every place around this forum for ALL personal opinions, however strong and thank goodness for that. There is no place for bullying though. Just as long as our opinions are shared and not forced, other asking their question can then make their own informed minds up. Thanks to those who have put web site details & I will update my own knnowledge on these pesticides