Topic: White Rot Resistant Onions

[steve1967]

Hi all newbie here looking for help and advice.  ;D

I have read that Golden Bear F1 onion seed are resistant to the dreaded White Rot. Has anyone tried these and what sort of success did you have and how did they store.

Steve

[Ellen K]

I have not grown them but they may be similar to Santero and a few people on here (Shirltone?) have grown it and been happy IIRC.

But these F1s are not white rot resistant - it's downy mildew they can grow through.

[saddad]

The best advice is not to grow them at all.  If white rot is in the soil the spores last for ages ... "resistant" crops just allow the pathogen to survive and build up... as it did with potato eelworm. You can grow them in containers.  :-X

[Ellen K]

You might think that container growing is a bit OTT for basics like onions but you can do quite well with fancy shallot seed and a small volume of compost.

I do it as the weed situation on my plot makes it difficult to grow such things in the ground,  I will take some pictures tomorrow so you can have a gander.

[cornykev]

I grow mine in raised beds now because of the WR with council compost and they are the best winter onions I have ever had.   ;D

[shirlton]

I did grow santero last year and when pulled they looked ok but they didn't keep. I think we are going to give onions a miss from now on.

[steve1967]

[/quote]

Thanks for all your advice on this matter. I am hoping I wont have to stop growing onions as it can take at least eight years to get rid of White Rot  ???

[chriscross1966]

One proven (I'll try adn dig up a link to the University of wherever-it-was paper) method of clearing white rot is to scatter adn dig in 100grammes per square metre (about 3oz a square yard) of garlic powder in the spring and then plant something that isn't onions..... the paper was proper science, they'd tried a couple of commercially available treatments, different levels of garlic powder, and more importantly had proper non-trated controls, isolation procedures and blinding etc....

Basically the commercial treatments (mostly American ones adn not allowed in the EU) were effective, but only if properly applied to complex instructions in some cases... Garlic powder was jsut a straight line in terms of its effectiveness, but hit 99.something percent around 80 grammes a square metre. I've tried it on half of one of my plots where I know there's white rot from last year. It got 100 grammes a square metre, I'll find out next year.... it isn't cheap (compared to some of the older treatments like drenching the soil in armillatox), but if I can get rid of white rot on my plot by digging in garlic powder then I'll happily do it....

[chriscross1966]

Here's the initial interim report http://oregonstate.edu/dept/coarc/sites/default/files/publication/93_garlic_powder_sclerotium.pdf  THe same team has done a lot more since but it's not eay to track down due to the significant amount of noise from allotment sites talking about white rot in the search results :D....

Based on their results they're looking at an application rate of around an ounce and a half per square yard as being 100% effective....

[saddad]

I'll certainly give that a go... I have a patch on my top lottie where a previous tenant grew nothing but onions for twenty


























I'll have a read and give that a go...  :)

[tomatoada]

I too would like to try this.   I googled garlic powder and got confused as to which to buy.  It seems to be aimed at treating horses.  Any advice welcome please.

[Ellen K]

Interesting isn't it?

Google "garlic powder germination stimulants" or similar and you get rid of some of the noise - returns the science mostly..

5 kg tub just under £23 (ebay) but maybe you could source cheaper elsewhere:

http://www.ebay.co.uk/itm/200732237391?var=500052012633&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649#ht_500wt_922

ETA: I would buy the stuff for horses rather than the human cooking stuff and sprinkle and dig.

[chriscross1966]

I got the stuff for horses, can't remember where  but it was on ebay, rotivated it in with the manure and chicken poo, BFB and Organic Extra (generic 6x I believe) before i put the spuds in.... it's not that cheap adn I'd be interested in any method available that will do the job....

[steve1967]

Here's the initial interim report http://oregonstate.edu/dept/coarc/sites/default/files/publication/93_garlic_powder_sclerotium.pdf  THe same team has done a lot more since but it's not eay to track down due to the significant amount of noise from allotment sites talking about white rot in the search results :D....

Based on their results they're looking at an application rate of around an ounce and a half per square yard as being 100% effective....
Thanks chriscross will definately give this ago.

[davyw1]

I tried it last year. i used equestrian powder £6 a tin putting it into a flower seive and sprinkling the ground where this years onions were going. I waited till the weather was going to be humid and rain (conditions for WR to activate) befor i did it.
So far all my onions both over wintering and maincrop are looking good but there is still time for Murphy law to click in.

[Plot22]

I have white rot which was completely decimating my onions. 2 years ago I tried the garlic powder which I bought from an animal feed outlet at £6 a kilo. There are 2 types a brown one and a white one. I have used both but the white one is the best as if there is any left the brown one  will go hard for the following year and the white one is also cleared for culinary use if there is some left will remain as a powder. The first year I spread it out a couple of weeks before I set the onion plants which I had grown from seed. I lost about 20% to the white rot but it was an improvement. The second year I spread it out in the early autumn when the temperature was high. The second year I set 300 onions as I expected a 20% loss but in fact I only lost 3 onions. The varieties I grew were Golden Bear, Hylander, Red Barron and a cheap packet of sets just as a back up. Last August I again spread the powder so fingers crossed for this years crop.
I also add for the last 2 years I have taken a leaf out my late dad's book and used the same onion bed. He never changed the bed just added farmyard manure in the autumn. Robinsons have used the same bed for years so again it works for them.

[Paulh]

Thanks for the reminder, I must get hold of a tub again.

I used it for several seasons a few years ago, and the white rot certainly was much reduced and has stayed low. Correlation is not causation, but ... ! I also keep an eye out for ailing plants and if one is succumbing, I tend to get the whole crop up at once, even if they are on the small side. Leave it for a week, and it can be a disaster.

I put the garlic powder on the site when it is clear during the previous year, preferably early autumn. I wouldn't want to be getting the white rot spores awake and raring to go and then plant my sets in among them!

[Tiny Clanger]

I've  found trying different patches in the plot has worked. Not always convenient, not always large size, but we get onions and garlic come harvest time.

[Deb P]

One advantage of keeping records fir my raised beds is that I can avoid planting any alliums in an affected bed, luckily only have one raised bed that gets white rot previously at the moment so not too arduous a task but I hadn’t thought of treating an area….might be an idea before trying alliums after the seven year rest!