Allotment Gardening Advice Help Chat
Growing => Grow Your Own => Topic started by: AndyRVTR on November 10, 2022, 13:49
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So after this years crop of leeks were decimated by ALM I've done a bit of reading up but I cant find an answer to my question.
The articles I've read say that it usually hits twice a year and pupae are most always found either on leeks/onions or in the soil. My question is, are any pupae from a second attack likely to remain in the soil over winter and hatch the following year possibly causing a repeat of what's happened this year or will they just die off.
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Yes, they are likely to remain in the soil. I spray the leeks a couple times with a Chrysantheum concentrate concoction during the critical months. Funny thing is, after being blighted by these pests over the last five years or so they seem to have been keeping a low profile over the last couple of years.
Anton
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Good info Andy.
I need to clear my leeks once my back stops playing up!
Certainly sounds dangerous to leave them hanging around.
I wonder what effect all this warm weather is having on them too. ??
A bit annoying as I usually thought of leeks as being relatively trouble free.
Cheers HH
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It’s a real pain. My plot it riddled with it. You can cut your leeks at ground level and they will grow back. But they will need extra fine netting in October / Sept. Can’t help with onions as mine seem to avoid it.
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In which months are the pests the most virulent?
Anton
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My onions seem riddled with it too
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In which months are the pests the most virulent?
Anton
We've had the ALM since 2014. for us the spring offensive happens around May 1st but unfortunately I've not yet been able to pinpoint the Autumn session. Internet reports say otherwise but we've found the spring flight to be worse than the autumn one. Certainly the first three years were the worst but it never goes away. Even though we now grow alliums under Enviromesh ultra-fine the fly still manages to get through and attack some bulbs.
Re Leeks being trouble free HH, we also get leek moth which I believe spread North as the climate warmed. Leek moth and ALM are supposed to fly at different times but one year our leeks were riddled with ally miner maggots and contained adult leek moths at the same time.
As mentioned above it is possible to watch as the alm grubs track down through the leek and cut it off at ground level just before they get there. The leek will re-grow but it's a gamble as to whether the adult has finished laying her eggs.
Onions, leeks and shallots etc can be completely destroyed by alm, garlic and elephant garlic survive as the grubs only attack the material that will become the paper. Not very nice though to have lots of brown pupae dropping out on the chopping board as you're preparing food to eat :ohmy:
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Clearly I had been lucky historically to have no issues with pests on my leeks.
I have solved my problem this year by not growing any but I am waiting to see if my onions /garlic/ shallots remain untroubled.
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Thanks Blewitt
Anton
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For the first time I grew leeks from seeds last year. They were doing really, really well and then some started showing signs of attack in November (when it was really hot for the last time). I pulled them up. The ones I left (replanted later on thus smaller than the other ones) survived and we eat them this spring.
I have sown under a net this year. Some gardener told me they grew their leeks under netting last year and had no problems at all. But they did not lift the net at all, not even to do any weeding!
Anton