Narcissus Bulb Fly Control

Danny Wylie via pbs pbs@lists.pacificbulbsociety.net
Wed, 01 Sep 2021 17:39:43 PDT
Thanks all for your help! I think I will try imidacloprid to start off and
switch to Spinosad or the others mentioned. I agree, it's good practice to
change insecticides so pests don't build up resistance. I also plan on
being careful in using these, don't want to harm anything I'm not intending
to. On a positive note I still have one large bulb that was not infested
and should bloom for me!

Regards,
Danny

Jane McGary via pbs (*Tue, 31 Aug 2021 10:52:41 PDT*)

I don't know how the life cycle of the bulb fly here in the Pacific
Northwest compares with other regions, but here, the adults emerge
simultaneously at a certain time in late spring and are immediately
apparent not only visibly but also audibly. When they are flying, they
produce a high-pitched whine similar to a mosquito but louder. At this
time I make sure my bulb house, which has metal screen sides and a solid
roof, is closed up. Bulb flies attack Galanthus (snowdrops) and
Sternbergia as well as Narcissus in the open garden but I haven't lost
significant numbers of those. I have read that the bulb flies are more
likely to land on plants in sun than in shade, but my garden is mostly
sunny.  I did plant a large number of commercial daffodil hybrids at the
road frontage, thinking the flies might be attracted to those cheap
bulbs and leave my special ones alone. When I lived in the country, I
grew Sternbergia in a raised bed and just threw a little sand over the
plants when the foliage began to yellow. I have also read that the flies
are attracted by the color of the withering foliage, which makes sense
as their larvae have to make their way into the center of the bulb via
the hollow left by a withering stem. Sternbergias go over well before
most Narcissus do.

When amaryllids are being grown in containers rather than in the ground,
just covering the pots with a sheet of row cover (Reemay, etc.) would
prevent bulb fly infestation and would not harm the plants. This product
is inexpensive and available online or from shops that supply vegetable
growers.

Re. Arnold's mention of Spinosad (spelling?), I tried it against cutworm
with no success.

Jane McGary, Portland, Oregon, USA

On 8/31/2021 4:52 AM, Arnold Trachtenberg via pbs wrote:









*LucaI’ve been using a number of new organic insecticides which represent a
new class of compounds.First group is based on bacteria that attack various
parts of the pests metabolismSpinosad has been around for a long
time.Grandevo and Vernerate are two others. You can search the names and
find info on the web and on you tubeThe most recent one is Spear-T. It is a
peptide derived from the Australian Funnel Web spider.I’ve had very bad
attacks of the Narcissus bulb fly and think there are some of my images on
the PBS Wiki.Arnold*


*Sent from the all new AOL app for iOS*


*On Tuesday, August 31, 2021, 3:10 AM, Luca Bove via pbs
<pbs@lists.pacificbulbsociety.net <pbs@lists.pacificbulbsociety.net>>
wrote:*


*Thanks Lee Poulsen*


*Do you have an alternative to imidacloprid?*



*imidacloprid and other neonicotinoids are banned in the
EU.https://ec.europa.eu/food/plants/…/
<https://ec.europa.eu/food/plants/…>*



*Il giorno lun 30 ago 2021 alle ore 23:20 Lee Poulsen via pbs
<pbs@lists.pacificbulbsociety.net <pbs@lists.pacificbulbsociety.net>> ha
scritto:*























*I didn’t see that anyone had responded to this. When I first
startedgrowing bulbs in pots (here in inland Southern California) I had
never seena narcissus bulb fly nor had any bulbs eaten by the grubs. Then
one year Istarted seeing these giant bumblebee-looking insects flying
around my yard.Starting the next spring, I started not seeing some of my
Narcissusvarieties never leaf out. When I dumped out the pots, I found
husks ofbulbs in them. Then I started finding grubs inside bulbs when
leavessuddenly wilted during the growing season. I tried various
non-insecticidemethods, but none of them ever worked. Finally I heard about
imidaclopridand found an insecticide that contained it. My grub problem
instantlyvanished and has never returned. There are issues with using
imidaclopridand damaging honeybees. So I only use it on my amaryllid bulbs
and a fewothers that are prone to this kind of insect damage. I sprinkle a
granuleform of them on my pots, never a spray that uses it. And I wait till
afterthe flowers are gone. (Because I worry that some of the insecticide
mightget into the nectar or pollen of the flower. It is systemic, so it
flowsthrough the plant and into the leaves and roots of the plant.) I also
tryto switch to some other systemic insecticide granules from a
differentclass of insecticide every other year so as to not contribute to
buildingup resistance by the narcissus flies. (I do the same thing with
flea dropson our cats. One month an imidacloprid-based flea drop, the next
month afipronil-based flea drop.)*




*--Lee PoulsenPasadena, California, USA - USDA Zone 10aLatitude 34°N,
Altitude 1150 ft/350 m*


*On Aug 29, 2021, at 5:42 PM, Danny Wylie via pbs <*


*pbs@lists.pacificbulbsociety.net <pbs@lists.pacificbulbsociety.net>>
wrote:*


*Hey all,*


*I've been in for a nasty surprise this growing season in northeastern*


*Ohio*




*as my bulbs have been hit hard by the fly. So far every 2 year
oldHippeastrum bulb has them. After I discovered them attacking most of
mylarge bulbs I wanted to try keeping the bulbs in my hot greenhouse*


*thinking*








*it would maybe deter them, but I was not successful. They will gladly
goafter any amaryllid about the size of a quarter. I would do the hot
watermethod but my bulbs get attacked so young that I fear I would never
seethem flower again. I'm researching insecticides for control and the
wikisuggests dylox. I've also read that a daffodil grower found
Imidaclopridhighly effective. Has anyone used these for containers and
found themhelpful?*


*Big thanks!*






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