First signs of downey mildew appeared a couple of days ago. We seem to get it every year now.
Snowball more affected than Centurion at the moment (both onion sets).
I have had it on both autumn and spring planted sets.
I tried spraying with Dithane a couple of years ago but without success.
Any advice on how to control it. or at least minimise the damage?
If you can get a hold of a substance called 'Tilt' this should cure it.
This is a commercial fungicide so you won't be able to buy it from a garden centre.
So if you know any farmers or commercial veg growers try them.
Its powerful stuff, you need something like a syringe to measure it out as I recall it is something like 2-3 ml per two gallon can of water.