latest wiki additions: bulb and iris flies

Jane McGary
Mon, 29 Jun 2009 19:40:43 PDT
Nhu wrote,
In only a couple of hours during the warmest part of the day, I caught
>4 Narcissus bulb flies! Imagine my shock to find so many flies buzzing
>around, trying to lay eggs.

My latest attempt to control these pests is to go out near a lot of 
daffodils in the warmest part of the day, as Nhu suggests, and nail 
them with the spray that is sold for knocking out wasp and hornet 
nests. It shoots about 10-12 feet and works best if the flies are at 
a considerable distance, so the spread of the spray catches them. So 
far no damage has appeared on plants the spray hits.

They seem to investigate colchicum leaves a lot, which is not one of 
their hosts. Fortunately, most of my species Narcissus are already 
withered away by the time the flies emerge, and so they're going 
after the common daffodils in the garden. I've covered the 
Sternbergia and Galanthus species in the bulb frames with Reemay 
(fabric that lets through light and air). In the garden, I 
experimented this year with heaping grit and sand over the centers of 
Sternbergias before the flies emerged, in the hope that this would 
prevent the ingress of the larvae.

Jane McGary
Northwestern Oregon, USA

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