Atm I have ladybirds:3 aphids:300.
A couple of years ago I made this brew with nettles and water. First I put it in a bucket and sieved it after 3 weeks (and boy does it stink) then I got lazy and used an old watering can (must be plastic) and just left it to ferment. Then tipped out the liquid into an old spray bottle hoping the gunge got stuck in the rose and blasted the aphids with it. Worked brilliantly once I'd remembered to dilute it Too strong and it burns the plant.
Felt v organic and wholesome (me that is) and ignore h's comments about my "witch's brew". Is generally a good plant strengthener.
So now am off to look for nettles. Why do you always have them till you need them?