Bulb Pests

[Paul T]

Out of interest, do you guys get blowflies over in the UK?

Also, how big are the actual Narcissus Fly?

[mark smyth]

Same size as a blow fly or drone fly - not a house fly. Paul your problem with three grubs in one bulbs wont be the same as our problem. It's most likely the small Narcissus fly. I have never has more than one grub per bulbs

[Maggi Young]

Yes, to the blowflies, Paul


 Just found this handy page: on  large Narcissus fly Merodon equestrishttp://www2.warwick.ac.uk/fac/sci/whri/research/integratedpestmanagement/narcissusflytreatment/

[Maggi Young]

And this , from PBS :http://www.pacificbulbsociety.org/pbswiki/index.php/NarcissusBulbFly


 and this pdf   http://64.233.183.104/search?q=cache:tgryzT4ErOoJ:www.which.co.uk/files/application/pdf/Narcissus%2520Bulb%2520Fly%2520302-445-92683.pdf+small+narcissus+fly&hl=en&ct=clnk&cd=1&gl=uk



small Narcissus fly, two species : Eumerus strigatus and E. tuberculatus

[mark smyth]

I will be using Chlorpyrifos weekly this year as soon as the flowers go over

[Martin Baxendale]

The narcissus fly do make a very distintive high-pitched whining sound as they fly, quite unlike the low drone of the bees. As I've said before, you'll often see narcissus fly try to mate with bumble bees, attracted to the bumble bees by their droning. But you'll also see them being roughly rebuffed. Also, where bees and bumble bees are mostly interested in flowers, going from bloom to bloom, narcissus flies are equally interested in leaves, alighting regularly on leaves, especially bulbs (snowdrops, narcissus, colchicums are all favourites to sit on) and will sit on the leaves basking in the sun.

The twits also (apart from their normal give-away whine) give off a particularly loud and high-pitched whine when two of them get together to mate, so it's often very easy to locate them locked together in nuptial bliss on the ground by the noise...and SQUISH them!!! Wa-ha-ha-hah!! Serves them right. They should learn to do it quietly.

[Martin Baxendale]

Mark, when you say the season was prolonged by the rain, do you mean the narcissus fly were emerging late because the weather was too wet in April/May? In which case, that fits with Armin's theory that the grubs alter their development and emergence to suit the weather conditions.

[Maggi Young]

Chlorpyrifos... I thought it was banned... what trade names is it under? Dangerous stuff, in my opinion, yet I suppose half the world is toxic in some way or another....

[Maggi Young]

They should learn to do it quietly.

there speaks a parent!

[Martin Baxendale]

They should learn to do it quietly.

there speaks a parent!

Have removed my rude joke before social services really do come to get me!

[Paul T]

We get LOTS of blowflies here, but we don't have bumble bees in Australia (well, outside of Tasmania anyway.... yet!)

Mark,

The grubs were about a cm long, so how much smaller are the lesser ones?  The grubs look very much like your pictures you posted, and from other links given the Meredon equestris.  The Crinum bulb these guys were in was about 4 inches wide.

[mark smyth]

I think it was the cool conditions that kept them alive for longer. Yes two get together there is a loud scooter/wasp in a can whine. During June while watching my swifts I always have a swat in my hand. Set some flat stones among the leaves for them to sun bathe on

Paul isnt there a major threat to Crinums and Amaryllis? When I visited Green Goblin in South Africa a grub was attacking his rare blue Amaryllis

[Paul T]

Mark,

That was the Amaryllis grub which I was initially talking about, but apparently (from response on the ABA list.  I'll try to pass on information up here as anything eventuates there as well, so that we have the information available to readers here too) they start by eating the leaves then head into the bulb, by which time they're 4 or 5cm long.  Definitely not my beasties.  Given mine had 3 grubs to the one bulb it is likely mine are the smaller narcissus fly, not the larger, although my grubs look very much like your pics.

[David Nicholson]

http://www.food.gov.uk/news/newsarchive/2001/dec/chlorpyrifos

but!

http://www.poptel.org.uk/panap/pest/pe-chlor.htm

I think this is one I will not use. Although I have said I don't appear to have trouble from the Narcissus fly (perhaps to wet and windy for it in my garden) I normally trickle a good quantity of dry sand into the holes left by dying back leaves. Don't know if this might help for others though>

[Hans J]

Maggi ,

here in Germany is aviable Chlorpyriphos until 31.12.2015 - the name of the praeparat is NEXION !
I have ask before 2 years by a Office from Agricultural what I could use to fight against Narcissus fly -they advices me Nexion .
I personly watering all my galathus bulbs as protection against Narcissus fly two times ( May +June ) since this time I hab not more problems -earlier sometimes .
Nexion I use for my sowing pots as protection against "Trauermückenlarven" -sorry -but I dont know the word in english -this helps really .
Further I use yellow stickers to catch the adult insects .

Sorry to report :
Yesterday I found in a big bulb of Phaedranassa a lot of larvae from Narcissus fly -one or two big one ...and a lot of small one ....grrrrrrr !- the bulb was complete destroyed but it has some good bulbils ...there is hope !.....now I know I have to watering also my other bulbs of Amaryllidacee with a insecticide !