[Raven50]

We have had an attack of Onion Fly, which has attacked all of the Onions on our site, not just on my plot. Is there anything I can do to salvage them? Do I need to dig them up and burn them? Are they usable, if not storable? How can I stop it spreading?
Any suggestions gladly received 

[Kleftiwallah]

This is what my 'Bible' "Successful Organic Gardening by Geoff Hamilton" says.

Hoe around the plants to expose grubs to the birds.  The female fly is attracted by the scent of the onions and this is strongest when the seedlings are thinned.  Grow from sets or multi-sown blocks and you will not need to thin plants.

That's what my hero says.     Cheers,    Tony.

[hubballi]

pull them up, soak the roots in water for around an hour thus drowning them. This year I took no chances and made collars for them to stop the fly laying eggs under the soil :-)