Bulb fly management

[Chuck]

I lost over 10 Hippestrum species several years ago to that Narcissus bulb fly. Right now most of my bulbs inside but they are not getting as much sun and I am getting to the point where there might be too many inside.

Are there any good ways of managing the flies in your collections of bulbs? I don't want to waste money to re-buy rare bulbs that I will lose again.

I read several nurseries soak their bulbs in 43C water for 2 hours.
Also remove the dead leaves.

[Ezeiza]

A systemic insecticide applied as a drenching every three weeks for the whole period of risk should solve the problem for good. The first drenching applied in advance of the flies appearance. The whole idea is to have the bulbs well poisoned when the first larvae hatch.

[Gene Mirro]

I use Dursban (Chlorpyrifos) on my Narcissus.  I spray the foliage in mid-May.  You will have to find out the proper time to spray in your region.  Dursban is somewhat restricted, so you may have trouble getting it unless you have a permit.

[Chuck]

The only trouble with the insecticides is that I have edibles around the yard. Do the flies go into greenhouses? or shade structures?

[pehe]

The only trouble with the insecticides is that I have edibles around the yard. Do the flies go into greenhouses? or shade structures?

Yes, they go into the greenhouses. Last summer I had an attach in my greenhouse. I killed one fly and gave my amaryllidaceae several waterings with a systemic insecticide. Time will show how much damage they made.
The rare amaryllidaceae that I grow outside is in a frame that can be covered with a thin netting mounted on a window-like frame. When it is too wet, it is covered by a window and in drier periodes with the netting. (That also prevent my cat sleeping there ).

Poul

[Alan_b]

I have not yet tried this but I have bought a large piece of thin-hole netting to cover the raised beds where my nicest snowdrops grow.  I don't see why this should not work.

[Ezeiza]

If your Hippeastrums are in pots you can take them to another spot for insecticide application. Of course by applying it you will be poisoning your vegetables.

But, on the other side, growing valuable Hippeastrums near ordinary vegetables that could transmit viruses to them is nonsense.

[annew]

Please be(e) aware that neonicotinoid pesticides including imidacloprid are implicated in serious declines of bee populations. It would be wise to only apply these substances, if at all, to plants after flowering to avoid passing on to bees through the nectar or pollen.

[pehe]

Couldn't Neporex, which is a pesticide used against fly larvae be useful? It is not harmful to adult flies (and probably bees)

http://www.afsanimalcare.co.uk/products/insecticides/ins_downloads/NEPOREX%20label.pdf

Poul

[Maggi Young]

Please be(e) aware that neonicotinoid pesticides including imidacloprid are implicated in serious declines of bee populations. It would be wise to only apply these substances, if at all, to plants after flowering to avoid passing on to bees through the nectar or pollen.

A timely point, Anne - In the UK it seems that the govt. minister will not follow the advice of a committee report that such pesticides be banned :   petition and info about this  here :

http://www.38degrees.org.uk/page/s/ban-the-pesticides-that-are-harming-our-bees#petition

[Chuck]

A timely point, Anne - In the UK it seems that the govt. minister will not follow the advice of a committee report that such pesticides be banned :   petition and info about this  here :

http://www.38degrees.org.uk/page/s/ban-the-pesticides-that-are-harming-our-bees#petition

That is probably also true here in California. Another alternative is to keep them all in the stairway. But there is not enough light. Right now everything is in pots each bulb I have is in separate pots. I have not put bulbs outside for 2 years. I noticed the fly goes after seedlings too but they have to be at least over 1 year old.

[Ezeiza]

Anne, no doubt that is true but it is a problem of scale: millions of acres sprayed with imidacloprid against ten pots that could not even flower each year.

[annew]

I appreciate that, Alberto, but I have been sad to see dead bees in my alpine house after applying imidacloprid to plants in flower. I still use it on ferns, and probably will use it if really necessary on plants after flowering when bee visits are not likely.