What has mangled my onions?

[dilettante]

Maybe this will be my crop disaster for the year, and I'll be blessed with glorious, bountiful crops for the rest of it

I first noticed when some of the leaves were twisted up. I've not actually seen that as a symptom of the leaf miner in any of my books or online, so I kept looking for thrips. There were holes in some of the leaves that looked more like a slug had taken a bite than anything else. Perhaps that was incidental. Next year I'll be meshing and fleecing everything.

[Scarlet]

dilettante, that's really bad luck ...
As you say, especially when it's so close to their harvest time ...
I'm keeping a very keen eye on my onions/garlic now ... What were the first signs you noticed? But suppose it's probably to late to do anything then though ...?

Usually by the time you notice it's much too late

[Scarlet]

Maybe this will be my crop disaster for the year, and I'll be blessed with glorious, bountiful crops for the rest of it

I first noticed when some of the leaves were twisted up. I've not actually seen that as a symptom of the leaf miner in any of my books or online, so I kept looking for thrips. There were holes in some of the leaves that looked more like a slug had taken a bite than anything else. Perhaps that was incidental. Next year I'll be meshing and fleecing everything.

I think it's relatively new..I'm sure I read it was first seen in 2002 in the South East. We've had it here now in the South West for about 4years or more. You can often see short brown dash marks in the green foliage, the holes were probably something else. It's gutting when you loose your crop. I lost all my garlic to white onion rot last year after netting! I feel your pain
Debris netting is what I use, fleece you can't peg it down well all the way around.

[Marcusp]

110% alium leaf minor. Had it on our loty site for the past 4 years now.
Their horrible little sods which were first found in the midlands and are spreading across the uk quickly.

Its a small fly similar to carrot fly that lays its eggs during the evening/night. The fly injects the onion by injecting eggs into the leaf which can be evidenced by lots of small white marks on the leaf in a line.
The eggs then hatch into pupae which feed on the onion causing the distorted leaves which usualy fall over and have flats spots and bulges before they move down to the bulb where they pupate and the cycle starts all over again.

The fly has two cycles. April/may and Aug/Sept.

There is no known chemical control and the only way to prevent it is to cover your onions, garlic, leaks with extra fine enviromesh or fleece making sure there are no gaps for the fly to enter.

It effects all the alium family hence leeks and garlic and once the plant is attacked usually secondary infection sets in like rot.

If you break open the leaves and bulb you will usually see the small white maggot which has a pale pink head or the little brown pupae near the neck of the bulb.

Dont leave effected plants in the ground as the pupae drop into the soil and hatch out in may/sept effecting further sowings. The only thing to do is burn effected plants.

Hope that helps and its a worrying little pest that seems to be spreading quickly accross the uk. The only way to stop it is to cover and destroy effected plants

[Markyw]

Yes I would agree that it is alium leaf miner, we have a big problem with it at our allotment, mine have also been attacked as well, will need to cover the next year.
It has not effected the Garlic which is good.

[Dalrimple]

only just seen this thread ,well it's here in north Derbyshire and on my plot ! 300 sets 4 types redbaron,sturon,alsia graig ,sillvermoon .the SM seem to be less afected but there's only a few worth picking i'll pull em up and burn em LOL it will smell like a hotdog stall on monday up the lottie ,
if it wern't for the bad luck i'd have no luck at all .
all the best Dal

[Marcusp]

Dal sorry to hear that I lost over 200 sets last year to.
As i said the only way to stop it is to cover them up from about March onwards just like your carrots from carrot fly.

Makes me wonder how farmers cope in the onion growing areas