you please tell me how to combat the narcissus fly? Every year I
lose some of my best hippeastrums to them.
gardeners have lots of trouble with bulb flies, because once they're
in your garden the cycle continues. As the foliage on your bulbs
dies down, the female lays eggs on the leaf bases, on the neck of
the bulb or in the soil nearby. The maggots hatch and burrow into
the bulb, causing rot.
One control method is
to make it difficult for the fly to lay its eggs on the bulb. As
the leaves start dying back, cover the bulb with several centimetres
Commercial growers sometimes
lift bulbs as soon as the leaves have died and submerge them in
water at 43°C for three hours to kill eggs and larvae, but this
is probably impractical at home. Alternatively, apply a soil insecticide
such as Liquid Diazinon or Soil Insect Killer to the soil around
the bulb as the leaves start dying down.
Gardener, Issue 143, 2004, Page 26
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.