Allium Leaf Miner

[Chantal]

Our site is now badly infected with Allium Leaf Miner. I took out around 400 leeks in the past few weeks and although stripped, cleaned and cooked down I froze around 23lb of them, I must have binned at least three times that amount.

The miner grubs have done some serious damage and rotted a good many of the leeks into oblivion. Although I would normally leave leeks in the ground and pull them as needed, it was becoming clear that to leave them would mean losing the lot.

Research suggests that currently there is no fix for this little ******* apart from covering the crop from sowing. That's a lot of covering and in addition to covering the cabbages, rocket, lettuce and carrots I'll soon have my entire allotment under cover!

Garden Organic are apparently experimenting with "cut and come again" leeks. They are growing them as normal until the leaf miners are flying and laying eggs, then cutting them down to the ground. The theory is that by the time the leeks grow back the egg season is over. However, would they not need to cover the cut down leeks to hide them and would that not mean mud in the leek stem?

I've already got leek seeds (Winter Giant) growing under a cloche at the allotment with a plan to get them planted out asap and a decent size before I have to pull them to save them. I'll still lose just as much, but will have more to save too as they mature really early.

Anyone else got any thoughts on this?

[Beryl]

I'm sorry you have it too Chantel. We have had it for a number of years now and the only way I can grow them successfully is under enviromesh or fleece from the time of planting out till about October then it is safe to uncover.

If you can catch it when you first see them cutting the leeks down early on so they have time regrow will give you an edible size leek but probably not what you are used to. Or hand pick off but they hide in the folds of the leeks and not easy to see, even then its almost impossible to find them all.

I now grow a shorter fat leek 'Pot Leek' but easy to grow under a tunnel of enviromesh.

Sorry I can't be of any more help. I wish you luck.

Beryl.

[AdeTheSpade]

Yes, we have had it here for several years now - they are such a pain aren't they. In the past few years (since we started having the problem) I've grown an early variety and not bothered to cover them, but harvesting them all by the beginning of October, and that's worked well and they've been fine. This year, I grew a different variety, I did cover them (but don't grow nearly as many as you say you do) and they've been fine. I'm positive if I hadn't covered them I'd have lost a lot.

[Chantal]

Thanks both, I hope my early sowing will work, but I may cover just some to be on the safe side. Fingers crossed.

[The Mouse]

This last year's leek crop in my garden is very badly affected by the allium leaf miner. The previous year's was too, but it's only this year that I've realized what it is.
In fact, I now think that the same thing could have been responsible for my onion problems for the previous couple of years (I didn't even bother to try growing them this last year). I was harvesting healthy-looking onions, but they were all rotting in store over quite a short time. Before they reached that stage, I was finding that some - random - layers within onions were brown when I cut into them - just like my leeks were last year!

I've read somewhere that once the problem reaches an area, there are three very bad years because of it, but then it seems to ease a little, supposedly because some natural predator begins to establish itself.
As this has been around in some parts of the country for some time now, I was wondering if any of you can vouch for the three bad years theory.

[Chantal]

I've just had my second bad year, but planted around 400 leeks to be able to harvest and rescue a quarter of the crop.

I dug the whole lot up in November and spent a week stripping them out and freezing. I have enough to get me through the year, but it takes up a lot of space growing so many.

This year we are planting less and putting them in covered beds from the start.

No sign of damage on the onions and only one garlic seems to have been affected.

Interesting, not everyone on our site seems to have a problem, including an immediate neighbour!

[Beryl]

Question Time in the Feb issue of TKG, Anne Swithinbank suggests planting out after June to avoid the first generation. Whole answer worth reading, page 18.

Beryl.

[bernie]

The downside to planting out in June is a much smaller crop.The only remedy is to completely cover with fine mesh,i know its a pain, I have had to do this for the last 10 years.
I haven't heard of this 3 year cycle its bad in Staffs every year now

[Westi]

I agree - got to cover them with mesh until it too cold for any critters to invade. I do love taking it off though as I really like the look of leeks standing with a touch of frost on them, especially the ones with the purple tint on the leaves.

Westi