Bulb Fly.

totototo@telus.net totototo@telus.net
Mon, 14 Dec 2009 17:54:19 PST
On 14 Dec 2009, at 20:44, iain@auchgourishbotanicgarden.org wrote:

> Could anyone spare a moment to tell me, if they know, what the Latin name for
> this pest species might be please, as well as the range of geophytes genera
> which it attacks? For example do any of the following genera such as
> Cardiocrinum, Gagea, Lilium, Nomocharis or Notholirion feature on its menu?
> Any info on its life cycle and or relevant literature references would also be
> of considerable interest as well. Under the name 'Bulb Fly' this doesn't ring
> any bells on this side of the Big Pond but if holarctic in distribution it may
> well occur under a different name here in Europe.

Lesser narcissus fly is a species of Eumerus, larger a species of Merodon. 
There may be more than one destructive species in each genus.

Both flies primarily attack members of the Amaryllidaceae, but will go after 
other bulbs in a pinch. I once found one in an ordinary hyacinth bulb (one of 
those fancy Dutch cultivars).

WRT to the genera you list, they are out of the direct line of fire, but may be 
attacked from time to time.

Life cycle: Adults emerge from pupae in the spring, from the first warm day in 
May well into July. Eggs are laid at ground level and the newly hatched grubs 
work their way down the outside of the bulbs and bite their way through the 
basal plate into the interior. They feast on the bulb until pupation, when they 
leave it for the surrounding soil.

The greater fly rarely has more than one grub to a bulb, but the lesser fly may 
occur in considerable number in one bulb.

Control: they're just stupid flies and nearly any insecticide will kill them 
*if* you manage to hit them.

The greater fly is distinguished from other bee-like flies by an distinctly 
audible whine when on the wing.

Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate
on beautiful Vancouver Island


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