Kitchen Garden Forum

My maincrop onions have been dreadful this year, for the first time. The tops have suffered what I suspect to be downy mildew, and have all died back, and the majority have thick necks that seem to be very wet - indeed some have already rotted from the inside.

I have pulled them , trimmed the tops and put them to dry, but I have two questions:

1) will they store?

2) What went wrong. Is it the wet season, or have I done something wrong

Checking on the internet, there is a suggestion that Mancozeb can prevent Downy Mildew. This is the active ingredient in Dithane 945 that I use for Potato Blight, but the packet does not mention onions.

Does any one have any experience/ advice thay can share with me.

Not wishing to be the bearer of bad news Ian but have your onions got white rot? This shows as a fluffy white growth around the roots and base of the bulb.
Hopefully it is the far less serious downy mildew and I suppose its the prolonged damp weather that has brought it on.

I would remove and burn all infected plants and for those that you can harvest and use in the kitchen I would dispose of all the trimmings etc in the dustbin. They probably won't store well so you'll have to keep checking them and bin any that are not keeping.

John

Down here in tropical Dorset the onions are attacked by a mildew, this year I was so pleased the way my onions were coming on the best I had ever grown, then we had a light mizzle type shower for about an hour on a Sunday night next morning I went up the lottie and the onions looked like they where covered in soot, I didnt have anything with me so I had to go out and get some murphy's copper fungicide which worked for a while but they did finally keel over after another few weeks, some people do also use dithane which when you read the packet should be used before anything attacks not after.

John,

Fortunately it is not white rot, which I have seen, and is not pretty.

I was afraid that they would not store well, si I will take your advice and keep checking them.