[pbs] Narcissus Bulb Fly - Merodon
Mary Sue Ittner
msittner at mcn.org
Tue Oct 30 10:15:17 EST 2007
Hi,
I wasn't sure I had a problem here in Northern California, but I do. It's
my understanding that they go for the big bulbs first so that you may not
recognize the problem as there may be some offsets surviving. The ones I've
discovered in my garden and my greenhouse have been in Cyrtanthus mostly.
It's happened enough now that if I see the foliage going down at a time of
the year when it isn't expected (or in something that is usually evergreen)
I dump out the bulb and look and sure enough it is mushy with a grub
inside. At first I thought I was just watering too much. I really love the
Cyrtanthus that they love too and I'm not sure what I want to do as I'm not
going to use pesticides on a regular basis. One suggestion has been to
cover the bulb when the foliage is drying off, but in my cases there was no
foliage dying back and the leaves are tall and any way of protecting the
plant would definitely take away from your pleasure in looking at it. It
reminded me of seeing the bulb collection at UC Santa Cruz Arboretum when
they were struggling to have a collection because of squirrels, deer, etc.
The whole collection was in a small screened enclosure where it was
impossible to see and enjoy most of the plants when they flowered.
The biggest disappointed was when they took out my large Paramongaia. I had
thought I wouldn't be able to grow it and had many years of finding what it
needed since my climate is a challenge for it. Then one year there was a
beginning of a flower scape and I was delighted since I really had given up
hope. But then the scape started to look sickly and shrivel, then the
leaves, and sure enough when I dumped it out, it was being consumed from
the inside. A few offsets on the outside of the pot seemed unaffected.
We've talked about this in the past. Dave Karnstedt provided a lot of
information since it was a problem for him with all the Narcissus he grew
so a search of the archives would provide more comments. We know it occurs
in Ireland since the link on the wiki to the picture of the fly and a close
up of the larva if from Mark Smyth and since he writes about Galanthus,
this must be a genus they like too.
I recently repotted two pots of Cyrtanthus mackenii (evergreen) which
normally blooms a number of times a year and is evergreen when I realized
some leaves were dying and the plant wasn't blooming. Both pots had been
getting pot bound and I knew I needed to divide them. When I dumped them
out, I discovered the biggest problem was the grubs eating many of the bulbs.
Mary Sue
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