[vron]

Hi there, we are having a shall we or shan't we grow leeks or onions on our allotment any more.
We have always grown a great many of each with good results except for the last 2 yrs when we were struck with the dreaded 'Alium leaf miner'

We decided that after last year we would net the leeks and onions as a precaution this year.

They grew extremely well until the local fox cubs decided to do the 'Foxtrot' all over the nets, taking then right down to the ground, not once but 3 times and they looked like 'crop circles' in a field, and yes we had to laugh in the end or go mad with what we would like to do if we caught them.
 
But what a disaster that was  So we thought we would take a chance and hope they will recover without the nets on at all.

Well that was an even bigger mistake, as yes you have guessed, Allium leaf Miner struck with a vengeance.

We lifted, soughted and save a small proportion of the crops.  Freezing the leeks and drying only the best of the onions after thoroughly checking them over again, then put them in the back bedroom for storage, this was back in Aug/Sept.

All was well until mid Nov, then we notice the odd midge in our kitchen and dining room also our living room.  Fly papers were used as I don't like flyspray, but they kept appearing.  

One afternoon I needed some spuds from the back bedroom and low and behold there were loads of these 'midges' on the windows, and yes you have guessed these 'midges' were actually the adult 'Allium Leaf Miner'

Well out came the 'big guns' yes 'Fly Spray' and zapped the lot.

The onion storage trays were all crawling with the 'flys' so the rotten ones were destroyed and the so called sound ones chopped up and frozen, or used asap.

All the midges/flys have now been eradicated from the house, but we still have that decision to make, do we or don't we.

[Trillium]

I wonder if not growing them for a year might break the leaf miner cycle? You could always try to source local onions and leeks, perhaps at farmers' markets.

THIS is the RHS's thoughts.

[vron]

Hi Trillium, we grow our leeks and the majority of the onions from seed.  

As for the shallots, only the largest and most healthy sets are saved and used from year to year.
This is the first time the Allium Leaf Miner has infected the shallots.

The Red Baron onion sets are sorced from a local garden center.

Yes we have wondered if we can break the cycle by not growing, but it seems that the pupae hibenate in the soil over winter to be awoken by the smell of any alliums growing nearby the following spring, so starting the cycle over again.

"Quote"
"The second-generation flies emerge from the beginning of October until mid November. The larvae of this generation then develop in their host plant until the end of November, and over-winter as pupae in Allium plants"

[allotmentann]

This sounds horrible and I suspect it will not be long beore it spreads our way too. There does not seem to be an awful lot that you can do, gardenorganic has this advice:

http://www.gardenorganic.org.uk/factsheets/allium-leaf-miner.php

I hope that you can find something that works and you are able to grow them again

[sunshineband]

Last season our maincrop leeks were decimated by the fly

This season not one to be seen.

I guess the birds must have eatne any lasting pupae in the soil, and of course the leeks were in a different bed

I was prepared to cover them if necessary, but no need this year.

No way of knowing what next year will bring

[vron]

We work on a 4 year rotation, the top 2/3rds of the plot is divided into 6 smaller beds, (plus a larger bed at the bottom of the plot)  and planted  out as below.
 
Bed 1a: early spuds / 1b: maincrop spuds.
Bed 2a: onions/shallots / 2b: all leeks.
Bed 3a: curly kale & broccolli / 3b: caulies & cabbages etc.

The larger bed at the bottom of the plot, is planted out as below.

Bed 4:  4 rows of roots / 2 double rows of runner beans / 2 double rows of peas, and finally the salad stuff.

Next year the above will move to
Bed 2a & 2b: the spuds
Bed 3a & 3b: onions & shallots & leeks
Bed 4: curly kale & broccolli/caulies & cabbages. The roots we just move to the other end of the same bed.
Bed 1a & 1b: runner beans/peas & salad stuff.

We have rotated like this for the past 4/5 years

We are rather boring with what we grow and only grow what we like to eat.