Bulbs > Galanthus
In fear of the Narcissus Fly
Maggi Young:
Don't do it all at once, Paul - you'll depress yourself. Though reading of Martin Baxendale patrolling his garden with a tennis racquet to swat 'em is quite amusing!
So many references in the forum - amazing what the little blighters can chomp their way through.
Alan B. and others also speak of the danger from Swift Moth caterpillars - let's face it - sometimes it seems there are armies of munching enemies in the garden, just waiting to ruin our day.
GordonT:
Sorry - I oughtn't to have posted this under Galanthus... it is just that bulb flies managed to ruin a large part of our future garden plans. Last year we gave up entirely on growing any Narcissi in our gardens. We bought a lot of Narcissus 'Ice Follies' in the autumn of 2012, and they made an impressive show in May last year. During garden expansion after the foliage had died down, I realised that I had to regroup the Narcissi. Every one of the bulbs was fly blown! The blighters didn't spare a single one. I checked all of our other plantings and all bulbs had been ruined.
I'll take my chances with Tulips and White Tailed Deer rather than attempting Narcissi again! :-X
mark smyth:
Thankfully last year until July was too cool for them to be active. Fly swats! I keep about four in the garden and one in the back pocket. Hit them hard! They like to bask on stones and large leaves. Every one I kill I give it a squeeze. If an ovipositor pops out I'm very happy.
Systemic pesticides all the way
and learn how to tell them from the good guys
Alan_b:
Narcissus flies come in from the top of the bulb and the entry wound should be obvious if you lift and divide your bulbs when dormant. If you cut-open the bulb (or the remaining husk) then the fly larva should still be inside. Therefore an effort-intensive way of dealing with the flies is to lift your bulbs when dormant and check for entry wounds. This is easiest if you plant your snowdrops in lattice pots. Obviously this doesn't much help the bulbs but reduces the numbers in the next generation of flies.
Swift moth larvae attack from the side or the base and I think they will also eat the large roots during the growing season. They sometimes eat only some of the bulb and move-on so some bulbs survive an attack and eventually recover. I suspect that they are particularly attracted to snowdrops as I have lost snowdrops from amongst other bulbs. I don't know whether they emerge from the soil at all until they pupate so I am trialling lattice pots as a means of restricting their movements, as all the well-fed larvae I find are too large to fit through the holes in a lattice pot. The moths are supposedly active from June to August and they lay eggs on the wing therefore any protective covering would need a very fine mesh to prevent the eggs dropping through. I also treat my soil with Nemasys 'Grow your own Nematodes', being the best hope I can find of achieving a biological control.
Edit: Good note on Swift Moths here: http://www.donsgarden.co.uk/pests/538?telephone=5
uvularia:
Thanks folks! Excellent info! Sounds like I need to stock up on Systemic Pesticide? Is there a particular one that works well?
I did read that Galanthus grown in permanent shade were less likely to get attacked? So I have gone for a north wall. Not the best place to show them off?
Does anyone think this works? I will definitely be clearing away old foliage.
I wonder if Bacillus thuringiensis would work as a biological control or Nematodes aimed at Vine Weevil? I prefer biological control. I use MET52 as standard in my compost to control Vine Weevil but not sure if the nematodes would go for Narcissus Fly larvae as well?
The sun is out! So time to take some photos...
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