Topic: Allium White rot

[Tee Gee]

I have been contacted privately re-white rot asking 'where does it come from'?

I thought I would open the subject up to you A4A 'experts' for your views on this quite common subject  ::) ;)

I have always thought it was brought on to ones plots with infected sets and/or transplants, grazing animals (manure), and movement of infested soil.

In terms of a cure this seems to be a bit of an 'open book'

Some say; don't grow any of the allium family in the same spot for at least seven years and I have also heard that digging the diseased plants/stems into the bed is a cure which at first glance I would say 'beggars belief'

Then I found this article; http://www.farmersguardian.com/fighting-allium-white-rot-and-the-uk%E2%80%99s-waste-problems-with-composted-onions/23430.article which gives some credence to the idea!

What do you think folks?

[goodlife]

Well I never had it untill I bought a garlic from seed company...it must come with that as all of the bought cloves were effected and only 2 of my own stock that were growing next to the bought lot... >:(...I can't prove it of course...but they are only sourse it could have come from...I don't compost even my own onion waste..and don't buy onion from shop...and otherwise it is always seeds or own stock..I haven't found it other parts of my plots so we'll see how it spreads..but I'll keep onions well away from that area now..
Yes..I've seen similar trial results too...where they use garlic sprays some time before planting to 'activate' the rot..starve it and then plant the crop....it sounds promising..even if it's not cure...but if we can live with it and still get reasonable crop..sounds good to me... ;)

[davyw1]

I agree with Goodlife, about garlic i have said it a number of times on here that it is the one the causes of white rot. But if you consider the space taken up by garlic when planted and not knowing you have infected your soil then we become the biggest cause of spreading it.
I also do not compost any of my onions that have for some reason or other are not edible, they wont burn whole so they get chopped up and then burnt.
I think as gardeners we cant achieve the success of composting as these people who do it commercially or scientifically as they have the equipment to achieve temperatures we cant. I think there are very few allotment compost heaps reach reach the temperature required to kill off any bacteria etc
It takes about 14 years for it to go or so it is said but from when do you start counting after every time some one walks on your soil.

[Tee Gee]

.I don't compost even my own onion

Oddly enough I do!

they have the equipment to achieve temperatures we cant.

I agree!

after every time some one walks on your soil.

Exactly!! This is the reason I started with narrow beds, so that I, and others, would keep to the paths rather than the growing area.

I recall many years ago a neighbouring plot holder walked straight over my plot and I knew his plot carried club root which can be transferred in a similar manner.

Needless to say I was not very happy with what he had done and I let him know and why >:(

Not that I am affected (touch wood) I have carried out a bit of an experiment this year.

As many of you will know I dose my brassicas with Armillatox to deter cabbage fly and I think club root; well I have done it to my onions this year in the hope that it will deter onion fly and possibly white rot.

OK if I end up clear of these problems I won't know if this is a result of my experiment or just 'luck'

And if that is not enough I have dosed my carrots as well and I am not gong to put up any barriers. So again will it be luck or the experiment?

I am still convinced 'smell' has a part to play in pest attacks!

And for the record; NO I don't have shares in Monsanto  ;)

[Vortex]

Yes Tee Gee Armillatox surpresses white rot - When I moved onto my plot I had it really bad in the first year and lost about 40% of my onion crop. I now treat every year 3 weeks before I plant and have only had 1 onion since that has shown any signs - even the ones over wintered last year (ie harvested in 2009).
Also the heritage variety up-to-date supressed from the national list, when it was drawn up, in farour of bedfordshire champion is resistant (which is of course why it was supressed - no profit to be made from it selling chemical compounds to supress white rot and rust)

[Vinlander]

I think as gardeners we cant achieve the success of composting as these people who do it commercially or scientifically as they have the equipment to achieve temperatures we cant. I think there are very few allotment compost heaps reach reach the temperature required to kill off any bacteria etc

The idea of using composted onion waste against white rot means you aren't doing the usual composting thing where you want to kill pathogens - the cure involves trying to create an essence of onion that 'wakes' the spores up and starves them to death because there are no real onions there.

It shouldn't matter if there are also some spores in the essence - so temperature isn't necessarily critical.

Presumably you're just trying to create the smelliest oniony mess you can and then you spray it on the place where you plan to grow onions later - next year? the year after? both? so many questions...

[realfood]

The fact that farmers are successfully using heat treated ( to destroy all allium  pathogens) onion waste, gives great credence to my earlier posting suggesting the use of garlic liquid or powder to trick the white rot into germination, when there is no allium crop to infect.
You can see details of this method here :- http://www.growyourown.info/page173.html

[Vinlander]

I don't see why killing the spores in the waste will make any difference - if there are spores in the soil.

If there aren't spores in the soil then you'd be mad to introduce them even if 99% get woken up and starved.

I'm talking about small plotholders like me who KNOW there are spores there already.

Why use expensive food products to lure the pathogen to death when you can starve both the the pathogen in the soil and the residual ones in your infected onions by mashing them up and spraying the stinky muck on next year's onion bed now?

I've read the MAFF document on the "lure and starve" method and there's nothing in there to say for sure which method works better on a small scale...

It is obvious however that the garlic powder/hot compost method is safer if you have, say 12 acres to rotate and one acre that hasn't seen onions for 12 years.

The garlic is also going to make someone a profit, and well might be easier to perform on a large scale.

[campanula]

MY allotment neighbour planted onions and garlic which she never harvested, just left to rot. The following year, myself and the plotholder on her other side had terrible onions althopugh we had always had good ones before.. This affliction has spread sideways over 4 years across the entire plot so I now grow onions in a bulbframe with clean John Innes. I am going to use this bed for several years, just replacing the top 6inches of soil, as I know Robinsons (giant vegetables) have been using the same onion bed for over 50 years. However, garlic, shallots and onions are no longer possible in the ground but leeks and spring onions are OK. I have no idea whether white rot was caused or exacerbated by leaving onions to rot in the ground but the timing of our onion failures, and the slow sideways spread suggests that there is a connection at least. This woman is a menace to everyone though as she will not give up her plot which has now lain fallow for 6 years! Oh, yeah, she had been planting potatoes in the same place for 3 years and then left them in too.

[Robert_Brenchley]

She shouldn't be allowed to hang on to it! Six years is too long.

[redimp]

I first mentioned this treatment my second year on this board when I discovered it the first year I had my plot.  I only get patches though and have never actually got round to trying it.  Might do this year though as the idea seems to be catching on.