Scottish Rock Garden Club Forum
Cultivation => Cultivation Problems => Topic started by: Diane Whitehead on January 24, 2007, 06:43:32 PM
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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?
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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 (http://www.srgc.org.uk/discus/messages/8/22416.html?1138098033)
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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!
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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.
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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
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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?
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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
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Northern location isn't a reason. We have narcissus fly in some gardens too. :(
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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
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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.
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This is from a MAFF (as was) publication:
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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.
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Anybody know where there is a photo comparing a narcissus fly, a good hoverfly and a bee side by side?
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Forgot to say, I cover my stock beds with fine mesh net once the leaves start to go, just in case.
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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)
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Getting there though. The large n fly seems to vary in its colouring quite a lot.
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Having a look at some images of bees on google, it seems that flies have much larger eyes than bees. Could this be used as ID if close enough?
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there is no confusing a bumble bee and a Narcissus fly only when the first small bumble babies are flying. Narcissus flies dont hover
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I did not know the Narcissus bulb fly existed before reading about it here on the forum. Good thing I did read this thread because last week I saw the fly in my garden and killed about 15-20 in two days.
Today I found a soft narcissus bulb with a fat grub in it so I guess the Narcissus fly must have been in my garden earlier in spring.
Narcissus bulb fly
Bulb with grub
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Today I found a soft narcissus bulb with a fat grub in it so I guess the Narcissus fly must have been in my garden earlier in spring.
That grub grew from an egg laid last spring or summer.
I wish some clever biochemist would determine what, if anything, is the scent that lures the narcissus fly to the bulbs. If it could be produced artificially, we could bait these horrible insects and perhaps greatly reduce their numbers.
Here in Victoria, it's a hopeless situation because the climate agrees so well both with narcissus and with the predator, and waste places often have feral daffodils that grow in spite of the fly and act as nurseries for it. Many of these feral daffodils are evidently famous cultivars from perhaps a century ago that have long since been superseded and perhaps lost in cultivation.
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Gunillas grub is very big to have been laid during May and June but adult Narcissus fly have stopped flying now in Europe. This could be a late developing grub.
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Well, the fat grub on my photo is not developing any more ;D
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Given how much trouble the Narcissus Fly can cause, how is it handled commercially? Do they spray with something, or just net the whole area as the bulbs start to head towards dormancy (i.e when the flies are likely to be laying eggs)? I can find very little information on it except from a home gardener perspective, yet it must be a big problem for bulb growers on a commercial scale. Does anyone know? How does the Netherlands deal with them? Giles article (fascinating read, thanks Giles) doesn't seem to sound like there has been that much found by way of chemical means either? Defoliation sounds a bit extreme to me, as it would likely affect the flowering for the next year wouldn't it? If you left it late enough not to, then wouldn't the egg laying already be done?
Gunilla,
I found one here last summer for the first time (grub in a bulb, not the fly itself), so they're here now too. I have to find out more myself now on how to treat them, because going out with a fly swat just isn't an option when you're working full time. There must be some method of treatment that can be used?
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Given how much trouble the Narcissus Fly can cause, how is it handled commercially? Do they spray with something, or just net the whole area as the bulbs start to head towards dormancy (i.e when the flies are likely to be laying eggs)?
Two methods: hot water treatment, which kills the grub; and insecticides, potent ones that have been outlawed in many countries.
There seems to be a myth that narcissus flies are like vine weevils, immune to most insecticides, but that's not true. They're just stupid flies and nearly any standard insecticide will kill them. The trouble is that almost no persistent insecticides are available to the home gardener these days (in British Columbia at least) and since narcissus flies can be on the wing for months (here in Victoria BC, from early May to the end of July), you either have to use a persistent insecticide or reapply any number of times.
Some 20 or 30 years ago there was a gal with a small commercial daffodil operation at Duncan BC, 30 miles north of Victoria. The story went that once DDT was off the market, she used chlordane, and when that went off the market in BC, she found a mail order source in Quebec.
I've heard many times that you can reduce the depredations of the narcissus fly by backfilling around the dying foliage with very fine, dry sand. This prevents the newly hatched grub from creeping down to the basal plate of the bulb. I don't know if this method works.
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Here is what DEFRA (English Agri department) has to say about them. They have done a study on them, in conclusion they haven't found much to control them since the pesticides were removed from sale but it does give a lot of info on the larvae, eggs etc.
http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=0&ProjectID=7941 (http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=0&ProjectID=7941)
You have to click on the 'Final Report'
Susan
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Rodger and Susan,
My sincere apologies. I thought I had posted in here a Thank You to you both for your responses. Either I am mistaken, or else this was another of my "disappearing posts" that seem to be happening from time to time. I read both your responses at the time and was very thankful for them. They confirmed a lot of what I had been able to find out myself. Hopefully the DEFRA site is not closed for too long, as i wanted to make a few references to it in an assignment I am currently completing for my Horticultural Studies, but the site is closed for maintenance. Murphy strikes again. ::) ;D
Could I possibly ask that any of you who still have information available on what was previously (or is still used in some countries where not banned) used to combat the Narcissus Fly, please let me know what chemicals were used? I am particualrly interested in the active constituent. There are no chemicals at all registered for use in Australia, so I am trying to find out what was used overseas up until they were banned.
Thanks very much in anticipation of any help.
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. . . what was previously (or is still used in some countries where not banned) used to combat the Narcissus Fly
IIRC, Methoxychlor applied every two weeks as a soil drench used to be the recommendation.
I've been told (iow, don't quote me) that methoxychlor, supposedly a biodegradable chlorinated hydrocarbon, invariably contained DDT as an impurity and much of its insecticidal virtue was due to the DDT. Truth? Slander? Urban legend? I do not know.
If you can group your amaryllids in one bed, a cover of cheesecloth or anything similar will suffice to keep the flies at bay.
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Thanks Rodger. From investigations, the cover does seem to be the most useful method of prevention, and the hot water treatment is the usual method of "treating" a possible infesting of the bulbs. Your confirmation is good, because it isn't suggesting something else I haven't come across (if you know what I mean). ;D
Every bit of information is helpful as this is a fairly major assignment, due in the next couple of days. I've just been struggling to find the chemical side of things, which is why I asked for further information. I realise that so much of this will vary from country to country as well, which is why the wide readership of these forums are so extremely useful to break down the borders and find out information we can't find. Do any countries still have any chemical recommendations in place, or does anyone have any other recommendations for previous chemical treatments?
Thanks again for your help, Rodger.
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Dursban was the best one in the UK until it was banned.
"A water dispersible granule containing 75% w/w chlorpyrifos. A broad-spectrum insecticide controlling many pests of agricultural, horticultural and forestry crops."
Other products contain chlorpyrifos.
"Chlorpyrifos is a toxic crystalline organophosphate insecticide that inhibits acetylcholinesterase and is used to control insect pests. Trade names include Dursban (home and garden uses) and Lorsban (agricultural uses)."
http://en.wikipedia.org/wiki/Chlorpyrifos (http://en.wikipedia.org/wiki/Chlorpyrifos)
Acetylcholinesterase
"Acetylcholinesterase, also known as AChE, is an enzyme that degrades (through its hydrolytic activity) the neurotransmitter acetylcholine, producing choline and an acetate group"
http://en.wikipedia.org/wiki/Acetylcholinesterase (http://en.wikipedia.org/wiki/Acetylcholinesterase)
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Paul,
Chlorpyrifos, the active ingredient in 'Nexion Neu' is avaiable here for application against larvae of flies in cabbage, onions and carrots.
But as usual it is allowed only for use in the crops mentioned.
I don't know if there are similar restrictions in countries outsite Germany or the
European Union.
Gerd
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I saw two Narcissus fly in the garden last week
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Thank Mark and Gerd. Your info has been added. ;D
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What surprises me (but I *am* easily surprised) is that no one has looked into developing a scent lure for the narcissus fly, either the scent of dying narcissus foliage or the scent of a female seeking a mate.
The one time I tried growing chlidanthus (in a pot), narcissus flies (both large and small) attacked and destroyed the bulb before it even had a chance to flower. One has to wonder if chlidanthus smells extra tasty to the flies and whether it could be used as a bait for them. Perhaps surround the pot with a wire screen enclosure with one-way entrances similar to those used in wasp traps.
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Good idea but would they make enough money? Only serious bulb growers would want them. Joe Public who grows Tete-a-Tete and loses some every year wouldnt buy it - I dont think. Commercial growers rely on hot water
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This is how you shouldnt leave tasty leaves in the garden to tempt the fly
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Mark,
Literature seems to vary..... do the flies lay on dying foliage, or dead foliage? Or is it that the early fliers start on the dying off foliage and then there are more for the next couple of months that then hit the dead foliage? I'm assuming that as there are flies around any of the warmer months the old foliage is hit as well? How far after flowering do you find that the first flies appear?
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I see them in my garden on green and yellow leaves. They also sample other leaves and stems. I dont know if they taste the leaves or smell them
The dead leaves belong to a well known N Irish gardener who never clears away the leaves
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Mark,
But are your observations always after flowering, or are there flies already laying eggs while flowering is taking place?
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Never while flowering and always when leaves are past their best. May and June for us so November and December for you
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Thanks Mark, that fits in with what I had worked out. So the Narcissus Fly you saw this week were probably from something other than Narcissus, looking for other Amaryllidaceae?
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No I think these would have been late to hatch. While repotting yesterday I found a Muscari that had signs that a grub had been eating it over the winter
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Well according to some of the stuff I've read, Narcissus Fly have been reported to feed on Hyacinths. ??? I had thought they just would have been flies that had been using a host on a different seasonal schedule.... surely if Crinum are being used as a host then eggs can be laid at any time over the summer months while there is greenery? I suppose the egg laying time isn't the issue though, is it? It is the temperatures that trigger the hatching of the flies from the pupae. Given hwo strange everyone's weather seems to have been this year it isn't surprising that they're confused. ;D Enough people certainly are. ::)
;)
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Paul they only fly for a month or six weeks and any Amaryllid is a target. When active I find them in the green house most days inspecting my Nerine sarniensis
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Unfortunately Paul and Mark, the larger narcissus fly is active in warmer gardens, at least here in NZ, for up to 4 months. I have seen them laying in October and as late as January, which is logical, considering how early Galanthus leaves are dying off, compared with later Narcissus or other amaryllids. My usual practice is to scruff up the soil where the leaves are dying away and make sure the holes left by the shrinking leaves are filled.
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Repotting Acis longifolium today, I found my biggest bulb with a *&*#*@! narcissus fly grub (the larger) protruding from the bottom. The entire basal plate may already have been destroyed by bacterial or fungal rot consequent on the grub's filthy excrement. I split the bulb in half, washed out the wound, and dusted the cut surfaces with sulfur in the hope that it's a fungus that the sulfur will bring under control. The grub I foolishly squashed before remembering that a photograph would have been of interest here.
At the current stage of its development, the grub was about the size of a grain of rice and had not yet hollowed out the bulb.
A reminder then that narcissus fly attacks all Amaryllidaceae: narcissus, acis, leucojum, hippeastrum. And it will attack bulbs of other families in a pinch: I've seen it in a hyacinth bulb.
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and look what I found just now. I'm now -1 N. 'Fairy Gold'. It's larger than I thought it would be for a month old
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and look what I found just now. I'm now -1 N. 'Fairy Gold'. It's larger than I thought it would be for a month old.
It could be considerably older than one month. The first narcissus flies of the season seem to emerge when the first warm weather arrives, typically in early May here, and I presume the first eggs are laid and then hatch soon after.
I'll confirm that this is indeed a grub of the larger narcissus fly: the wrinkled skin and the black tubercle at one end (used for breathing iirc) are characteristic, as is the orange-ish feculent mess of digested bulb tissue it excretes. Your photographs also show the staining of the area around the basal plate of the bulb due to rot setting in. If anyone reading is, is married to, or knows a helpful microbiologist, it would be of interest to find out just what organism causes that rot.
One has to wonder if perhaps the grubs harbor the rot organism and introduce it into the wounded bulbs.
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That doesn't look like the basal plate. The hole is in the side of the bulb. Maybe it is a much older grub and was on its way out to pupate in the soil or whatever they do? Is the basal plate still intact Mark? In which case the bulb may well survive if cleaned up and produce a new bulb or a number if bulbs from the basal plate.
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Yes the basal plate is intact. The grub went for a swim :o I can confirm that the black spot is it's a$$ going by the way it moved ?forwards
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Yes the basal plate is intact. The grub went for a swim :o I can confirm that the black spot is it's a$$ going by the way it moved ?forwards
Lucky you!
Looking again at the enlarged version of your photograph, you'll notice that not only is the wound on the side of the bulb but it's very large. These grubs will migrate from a bulb they've totally devoured to another one nearby. As far as I know, a newly hatched grub bites its way into the victim bulb through the basal plate.
In your shoes, Mark, I'd wash the bulb under a hard spray of cold tap water to remove feculence, then maybe a quick rinse with alcohol, and allow it to dry for a day or two before replanting. Packing the cavity with sulfur might also be a good idea: it's an excellent long-lasting fungicide and as Paul Christian once said at a study weekend I attended, it stays where you put it.
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Well I think David Lyttle (NZ Field Trips) is a microbiologist, if you're reading this David? A little after hours project for you?
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I found one here last summer for the first time (grub in a bulb, not the fly itself), so they're here now too.
Paul if what you say is true as Narcissus fly is not reported to be in Australia, I would suggest you investegate further with what was infected and if you see them again just squash them, forget the chemicals, there would be nothing regerstered for use because the fly is not reported to be here.
cheers
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Dursban was the best one in the UK until it was banned.
"A water dispersible granule containing 75% w/w chlorpyrifos. A broad-spectrum insecticide controlling many pests of agricultural, horticultural and forestry crops."
Other products contain chlorpyrifos.
"Chlorpyrifos is a toxic crystalline organophosphate insecticide that inhibits acetylcholinesterase and is used to control insect pests. Trade names include Dursban (home and garden uses) and Lorsban (agricultural uses)."
http://en.wikipedia.org/wiki/Chlorpyrifos
Acetylcholinesterase
"Acetylcholinesterase, also known as AChE, is an enzyme that degrades (through its hydrolytic activity) the neurotransmitter acetylcholine, producing choline and an acetate group"
http://en.wikipedia.org/wiki/Acetylcholinesterase
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Stephen,
What I found were 3 little grubs in a Crinum bulb. They matched the descriptions. I had been told it was in the Sydney region, which was why I was figuring it was the Narcissus Fly. The bulb itself appeared intact, except that it wasn't growing. When I checked it out the inside was rotten and these 3 grubs were in it. I had had the bulb for a few years, so it wasn't something newly introduced into my garden. I'm trying to remember whether I photographed them at the time. I know I mentioned it up here, and I "think" I showed a pic. Using the search function is pointless for me, as it never seems to work properly, so if anyone else can find the reference that would be wonderful.
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Paul, you mentioned it here: http://www.srgc.org.uk/smf/index.php?topic=1188.msg30589#msg30589
but there is no photo.
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Thanks Maggi. Maybe I didn't photograph them then. There were 3 small maggot grubs in the Crinum, in a puddle of dark gunge like is outlined in other descriptions of the damage they do. ::)
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There were 3 small maggot grubs in the Crinum, in a puddle of dark gunge like is outlined in other descriptions of the damage they do.
Remember that there are two kinds of narcissus fly, the greater and the lesser. The greater is, iirc, Merodon equestris and closely related species, the lesser Eumerus strigatus. The smaller fly has grubs very different from those of the larger fly. Paul's photo of a grub is unquestionably the larger fly, but I wonder if the "small maggot grubs" in his crinum may have been the lesser fly. Its grubs look like small slugs in a way; more importantly, they occur in considerable numbers in the bulbs they have attacked, whereas the larger fly's grubs are usually solitary, only one per bulb.
Incidentally, my earlier advice in another posting to this thread recommending that you wash away the bulb fly's feculence may be mistaken. A discussion of the larger bulb fly at
http://www.pacificbulbsociety.org/pbswiki/index.php/NarcissusBulbFly
specifically says it possesses anti-fungal properties and is better left in situ.
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I had wondered that myself (larger versus smaller Narcissus Fly), Rodger. Mark's photo (not mine) of the grub is certainly a more substantial beast than mine were, but the Crinum was also a fairly good sized bulb, so I thought it may have been multiples of the larger one due to the extra space. Still, if it is not here in Australia, when maybe it was something else. Stephen, do you know of any other grubs that might affect bulbs in a similar way here? I'm still nearly certain that someone in the Sydney region told me that they get it there. It would be very nice to know it isn't here and that mine were just some sort of maggot that was an aftereffect of a rotting bulb, rather than the initial cause of it. :o
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Hi Paul,
there is a caterpillar Spodoptera picta that will totally destroy Crinums and the Lilly borer a Brithys genus will also do the same destruction, eating all foliage and attacks the bulbs.If you dont see the caterpillar devouring all you see is the destruction and excrement, some case's where they pupate to fly off as moths.
There is a white curl grub about 1cm long that loves eating the roots of bulbs(lilies) and soft perennials in pots and well composted gardens.Found in early spring and suspect nothing from above until there is no growth to pull up the plant and find the grubs and no roots or with lily bulbs nothing but excrement.
Need a photo for a positive id and if you see their case's keep them in a jar and watch them pupate...hope its not the Narcissus fly.
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Narcissus Fly: see also these pages :
http://www.srgc.org.uk/smf/index.php?topic=4405.0
http://www.srgc.org.uk/smf/index.php?topic=4297.0 lesser narcissus fly
http://www.srgc.org.uk/smf/index.php?topic=1850.0
http://www.srgc.org.uk/smf/index.php?topic=3690.0
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Now, for those on Facebook, there is a group gathering information about the various colour forms of this pest and seeking reports of sightings.
https://www.facebook.com/groups/933733623318180/ (https://www.facebook.com/groups/933733623318180/)
Merodon equestris UK recording group
Natalina Bonassera
"The main aim of this group is to record Merodon equestris sightings to build a picture of its colour form variation in the UK.
Merodon equestris is a polymorphic hoverfly known to have at least 34 different colour forms.
The data gathered from this group will be used in an MSc thesis aiming to shed light on where Merodon equestris is most frequently seen, its emergence times, and geographical spread of colour forms across different areas and habitats in the UK.
I would be very grateful if photos of any sightings of Merodon equestris in the UK could be posted on this group. Please include a photo, date, location, details of habitat type (urban park, garden, meadow, woodland ect.) and grid reference. If you are unsure of what your grid reference is then here is a link to a helpful web site called grid reference finder, where you can find your grid reference http://www.gridreferencefinder.com/. (http://www.gridreferencefinder.com/.)
This group is open to anyone, whether novice or expert. Here is a link to Steven Falk's photo album of Merodon equestris on Flickr to give you an idea of what this species looks like https://www.flickr.com/ (https://www.flickr.com/)…/63075200@N…/sets/72157629553247540/.
All the records posted on this group will be passed on to the Hoverfly Recording Scheme.
Please join this group, add friends and share it with anyone who records or has an interest in hoverflies!
Thank you! "