Narcissus bulb fly

[Diane Whitehead]

I thought the narcissus fly looks for narcissus leaves to lay its eggs, and therefore having something like a hosta grow its new leaves to cover the dying narcissus leaves hides them from the fly.

A speaker last night said the fly is attracted by the scent of dying leaves, which have a different smell from green ones. He said growing narcissus in the shade of a deciduous tree or shrub helps protect them, and proposed that it might be because shaded plants continue to grow for a longer time.

This raises a question:  if the fly is active only at a certain time, and since narcissus have a long growing period, do early or late ones vary in their susceptibility?

 I think interplanting my narcissus with strongly-scented herbs may help confuse the fly's sniffer.  They will also persist, as deer like neither herbs nor narcissus (unlike hosta, which I have given up growing.)  Has anyone tried this?

[mark smyth]

Diane I have had bulbs in full sun and full shade eaten by the grubs. The fly also entered my glasshouse to lay on the Nerines. They eat any bulb that look like a Narcissus. Anyone who says they havent got them is wrong. The only way and time costly way to kill them is to buy and use a hot water tank. I now remove all bulb leaves at the end of May. The fly hatches in June
http://www.srgc.org.uk/discus/messages/8/22416.html?1138098033

[Maggi Young]

Mark, we really do not have this pest, I'm as sure as I can be!

Lesley, I know you're here, look at the ranunc page and the field trips page, please!

[Lesley Cox]

While I can't help with your specific enquiry Diane, I'd like to say that it's not so much Narcissus look-alike leaves the fly will attack, it is Amaryllidaceae generally so that they go for Narcissus, Amaryllis, Nerine, Galanthus and ALL related genera. They don't attack say Allium or Lilium and their relatives.

I can't speak for the north of course, but I think it's a bad mistake to assume the flies will hatch in summer and be active for just a short time. I have often seen them flying from October (mid spring) and through to April (mid autumn). It may be that there is more than a single generation involved.

Apart from very quick action with a fly swat when they are flying or resting, I find the best defence is the application when planting - either pot or garden - of a few grains of a (dangerous) substance called suSCon Green (the capitals are used like that). I think it comes from Germany though not absolutely sure. It is used in NZ for the control of pasture-dwelling pests and is extremely effective, and said not to be harmful to worms. It also controls the grubs of vine weevil. Unfortunately it is no longer available to the general gardener here but only to agricultural contractors who must be licenced and have special training in the use of hazardous chemicals. Luckily I have a quantity left from when it was able to be purchased.

[mark smyth]

Maggi do you have many Amaryllids in the garden? Maybe you are too far north? You need to watch on a still sunny day. They love to sun bathe

[Maggi Young]

We don't grow that many amaryllids, other than the narcissus, really, since it is too cold for most of them in our garden to thrive, Crinums freeze etc! But the glass houses are stuffed, of course!
I really haven't seen them here, certainly never found any critters in a bulb. I don't want to, either!!
We'll see if chum Brian Wilson who lives down the road, less than a mile away, has seen them... he's about here somewhere... hello, Brian... have you gone offline?

[jomowi]

Maggie

I was just about to shut down for the night.  No, I cannot recall ever seeing anything I was certain was Narcissus fly or indeed their larvae when we have lifted susceptible bulbs.  I hope I am not just unobservant.  I have had mouse damage to a variety of bulbs and Botrytus damage to Galanthus 'Freds Giant'  This causes rot apparently starting in the sheeth which surrounds the leaves as they grow through the ground. 

Maybe Aberdeen is just too cold for the fly to thrive although other root fly such as that infecting carrots do very well.

Brian Wilson

Aberdeen

[Olga Bondareva]

Northern location isn't a reason. We have narcissus fly in some gardens too. 

[Maggi Young]

Some new photos been posted to the Pacific Bulb Society's wiki pages:
http://pacificbulbsociety.org/pbswiki/index.php/NarcissusBulbFly


 see also this thread on the forum here: http://www.srgc.org.uk/smf/index.php?topic=3690.msg96867;topicseen#msg96867

[Lesley Cox]

I wish ALL the ruddy things were mounted on pins!!!

It would be helpful to have a picture of the mature SMALL narcissus fly. I've had a couple of bulbs with many small grubs, so must have a few flies about in the spring/summer but I don't know what to look for.

[Giles]

This is from a MAFF (as was) publication:

[Lesley Cox]

Thanks Giles, perhaps not wildly helpful but I'll keep a sharp lookout come the spring. The large one flies here over a longer period than in the NH so far as I can gather from Mark Smyth's comments. Usually from October until February and presumably lays eggs during all that time.

[annew]

Anybody know where there is a photo comparing a narcissus fly, a good hoverfly and a bee side by side?

[annew]

Forgot to say, I cover my stock beds with fine mesh net once the leaves start to go, just in case.

[Giles]

Not what you asked for, Anne, but might help all the same.
(from:  A Colour Atlas of Pests of Ornamental Trees, Shrubs and Flowers; by David Alford)