Merodon equestris (Narcissus bulb fly, greater bulb fly, large bulb fly, large Narcissus fly)
bonsaigai37@aol.com (Wed, 14 Nov 2012 10:01:58 PST)

That would be... "A granular -applied- once a season..."
M.

I've been using a product containing Imidacloprid to control the beasts. A
granular allpied once a year during Merodon flight/breeding season will usually
keep the critters from infesting bulbs, especially the ones in pots. In ground
control can be trickier. I'm less apt to apply Imidacloprid to the garden, as
it is systemic and will kill other beneficial insects.

Its use will also cause mites to become "extra-fecund". The population can
explode and predators may have been eliminated.

I always use pesticides will great caution, regardless of product. Sometimes,
it's just necessary.