Onion white rot

[caroline7758]

My oniions have grown to a good size but I dug a couple whose leaves had gone yellow and find they have white rot.  :( the rest have their leaves bent over but still green. should I lift them all now?

[caroline7758]

[saddad]

I would... make a wire frame to hold them off the ground while the foilage dries off... so you can keep an eye on them...  :)

[caroline7758]

Thanks, saddad, I've got just the thing to make that, and it means I don't need to weed the bed again, just dig the whole lot up!I presume weeds from that bed could spread the rot, too (probably already have done as I didn't know about it) ?

[saddad]

The spores could travel on the weeds... if there was soil on the roots...  :-X

[Vinlander]

It's worth keeping an eye on the leaf tips from mid-june: - as soon as they go yellow start gently tugging at the onions - pull with about 2x or 3x more force than the weight of the bulb.

a) The ones that come out you will see have shrivelled roots which is the first sign of damage - if they don't have visible white mould these onions will dry off and keep for maybe a month or more.

b) If you see white mould do immediate surgery and cook them the same day (if there's a lot then well-packed fried onion keeps for weeks in the fridge).

c) If the onions still hold the soil a few weeks later but the leaves are yellow down 25% of their length then take no chances and pull them out anyway and dry them off  - they aren't going to grow any bigger with dying leaves.

This year with the hot spring I had 90% out of the ground by 1st August. My neighbours were doing drastic surgery on many kilos of onions in early August - I had a similar sized harvest weeks earlier but only had to carve up maybe 300g in late June.

I find this technique leaves me with the "c)" onions hardly ever rotting in store whereas the standard advice to leave them in to some arbitrary date can end up with 25% being lost to rot - even if you carefully string them up.

It's a lot better to use this method and then just hang them up in onion bags - without the need for stringing it works out as less effort overall and a lot more usable onions through the winter.

Cheers.

[jennym]

Must agree with Vinlanders method, it echoes what I do now and does save a lot of heartache later on.
I do find that onions grown from seed rather than sets seem to give better results though.

[cornykev]

I have been getting a fair bit of white rot for the last few years
I do as Vinlander says and look for the looser onions and lift them early
What confuses me is some of the onions go full term with quite a large bulb and good greenery, but still have the rot on them
I was thinking about the weeds that grow in the same bed and possibly carrying the spores, so I put these to one side
When I pulled a really bad one I noticed that there was a large activity of insects, tigerworms, woodlice etc underneath, these will surely spread the disease, no
??? :-\

[pigeonseed]

It's rotten isn't it? It's my first year getting it, and I've had a lot of loose onions and shallots, with a tiny tiny bit of white fuzz at the root. If I leave them uncleaned they rot quickly, but if I clean them at home and dry them, they've lasted a few weeks so far and not got worse.

None of them has shown any problems above soil, and have in fact grown enormous.

But it's so annoying I grew so many this year for storing.

Onion chutney... fried onions... onion grated into sauces... onion with everything!!!  :o

[Robert_Brenchley]

I've had next to none this year, for a change. I haven't done anything different, so maybe it's the dry weather discouraging it.

[pigeonseed]

Has it been very dry for you? It's been pretty wet here. But good news on avoiding white rot.

I've been digging the weeds from the onion beds into the bed, but before I realised, I used to put them onto the compost heap - do you think it does spread that way?

[Robert_Brenchley]

Horribly dry. Other people get rain, and it always misses us.

[triffid]

Just adding this link here as a possibly useful bit of info from commercial growers on dealing with white rot using natural control. It's from 2009 and I It obviously works the same way as the garlic-solution method that was being chatted about yesterday. 
http://www.farmersguardian.com/fighting-allium-white-rot-and-the-uk%E2%80%99s-waste-problems-with-composted-onions/23430.article

Anyway, has anyone tried this? I can't find anyone on my site who has done.... But having picked up the dreaded fuzz for the first time this year on two or three of my onions and several shallots in different patches of my plot I think I may give this a go as a preventative where I'm planning to plant onions next season. Can't do it in the patches where I've had the rot this year as I've already got savoy cabbages transplanted there.  But I did mark the "aaarrgh!" spots with bits of old bamboo cane, so I suppose I can try it there next spring once the soil warms up...

[InfraDig]

I read in one of Charles Dowding's books, I think, that growing Brassicas weakens white rot and makes it manageable. I am not sure exactly how you go about it. I would have thought that if you have any rotation then you would have one year of brassica before growing onions again in the same spot. Perhaps Charles is around and could explain? Many thanks.