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.
Downy Mildew on Onions
Moderators: KG Steve, Chantal, Tigger, peter
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
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
The Gods do not subtract from the allotted span of men’s lives, the hours spent fishing Assyrian tablet
What we observe is not nature itself, but nature exposed to our method of questioning Werner Heisenberg
I am a man and the world is my urinal
What we observe is not nature itself, but nature exposed to our method of questioning Werner Heisenberg
I am a man and the world is my urinal
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.