An alert to the ongoing problems growing onions and maybe leeks and garlic! Onion fly (a fairly new pest to uk) is now rife at Highgate, causing distorted leaves, outer skin and maybe into the roots on onions and leeks. Check for small yellow fly pupae and see photo below.
RHS has no chemical remedy, so don't try spraying, as you will just waste your money and possibly end up with residues. We may have to grow under fleece, similar to carrots.
For more info- contact me. Dan Hackett, plot G5