Kitchen Garden Forum

I am in my third year on my allotments. The first year i lost a few onions and quite a few shallots to what an old timer called onion blight,the leaves yellowed and wilted with the roots rotting off.second year,at the other end of the allotment same thing again but i noticed that as soon as they started to look slightly off the y were not really attached to the ground and the bulbs had a white powdery looking mould on the base.Again i was told not white rot but blight.Third year new allotment but same problem started to occur so i pulled the whole crop and dried wellbut a good percentage have gone mushy.
Does onion blight exist?And does this sound like it ,or is it white rot?

Think the old timers are wrong this time Nickd. Sounds like White Rot to me. The symptoms are leaves going yellow & dying back, roots rotting off and a white cottony fungal growth on the bulbs which should have tiny black bodies within in. The black bodies are the bits that lay dormant in the soil for years and affect future crops. Bad luck you

Sue

thanks sue i was starting to think so myself but new plot this year been fallow for past five years. i must have contaminated the plot myself.

White rot can persist for seven years, so it may well have been in the soil.

Hi Nickd,
There is another scenario which could be occurring.
If your onions are very heavily infested with Onion Root-fly they eat the roots away and all manner of disease will set in but not necessarily White Rot.
Generally by the time you find this out the grubs have pupated and gone into the soil so it is just possible that the 'old boy's' are correct.
It is not my intention to confuse you but I feel you must question the 'old boy's' a little more to find out exactly what they mean.
JB.

thanks for the advice,and i am a bit confused about it my shallots which i grew next to the onions are fine(sadly the garlic wasn't so lucky).

Ever keen to state the obvious - why don't you just move the whole lot to another part of your site whilst you ponder the cause........

yes i keep moving them three different areas on two allotments every year the same. I only lose about 25% of onions but is annoying.

Do you get the onion sets from the same supplier each year?

Just wondering if that's where the problem originates?

On another allotmant forum the general opinion is that the OWR is in all the soil on practically all alotments. I don't have the problem the same, just a bit now and then, but this may interest you. I always grow my onions from seed, in multipurpose compost. This year not all of them were planted and a significant number were still in their 7 cm square pots thoughout the summer with automatic watering and an occasional feed. When we came to clear up the pots there was a very useful harvest of quite large size onions and no OWR. I therefore suggest that if you wish to grow onions without white rot or whatever then try growing them in containers, fishboxes will cost you nothing and a large sack of multi- is only about £3 and will fill several boxes.
Allan

I have been having problems with all my alliums for the last 3 years. The land i've been growing onions on was intensively used by the previous owner for mostly potatoes and onions (I recently found out).

I am not entirely sure what it is. I had thought it was onion eelworm given the distorted leaves but having read this post i am not sure. Has anybody any ideas????? Symptoms are as follows:
Green tops grow gnarled and curled instead of straight up.
The bulbs have a yellowy colour, mealy and do not store
If i prise the bulbs apart somtimes i can find small grubs. (i thought eelworm were so small you couldn't see them).
The roots appear to be healthy and no apparent mould.
I have noticed some white mouldy looking stuff occassionally once i open up the bulbs, but I am not sure if that is just the bulb rotting once in store.

Last year was not so bad it only affected about 50% - rather than the whole lot as in previous years. I spread loads of bonfire ash and put them in beds following lettuces and brassicas (which are apparently are the only two veg that do not play host to onion eelworm). I yanked out any plants showing signs of distorted leaves & burnt them. Previously i put them in the compost heap which was a bit dumb.

But I want a better crop this year. I have changed supplier, in fact i bought maincrop onion sets and garlic bulbs in Italy and i am growing the rest (shallots, speciality onions, onion blanc, leeks etc) from seed. It would not be feasible to grow them in trays or pots here because June Yuly August are just too hot & dry for that.
Any ideas much appreciated

Dear C.J, I'm afraid you could be right, it certainly sounds like onion eelworm to me too.
The onions will tend to rot if you try and store them.
The big problem you will have, is even when the onions reach a decent size if they are infected with the eelworm they will pass it on to healthy onions in storage, so you must burn any with distorted leaves whether they have made a bulb or not.

Really you need the ground to be empty from onions or any host plant for two years, but since this is fairly unpractical, i think i would just be ruthless and burn any infected plants.
I don't know if you could keep one section of ground for just growing brassicas and lettuce for two years and try and break the cycle like that, and please don't say you suffer from club root as well.

As for the little grubs, they could be onion fly maggot, it's much the same way of dealing with them i'm afraid.

This sort of problem really gos to show it doesn't pay to grow the same crop on the same piece of ground for too many years on the trot.

Sorry for the bad news C.J, I would like to be wrong.

Thanks OH

sounds like i have 2 pests for the price of 1

I will keep the land just for Brassicas & Lettuces as we generally grow a lot of them.
Luckily no clubroot

Do you think i can i eat them instead of burning ?

I am hoping the change of supplier will help and now i don't put any alliums in the compost. I think i may have been exacerbating the problem by putting dodgy, including mealy, shop bought (we had to buy them when our crop was no good!!)onions & garlic peelings in the compost.