My area is a bad one for narcissus fly as narcissus has been a commercial crop here for a very long time (a century or more). I'm not growing hippeastrums outside, but for other bulbs susceptible to the narcissus fly, like daffodils and snowdrops, I try to avoid the fly rather than poison it. The base of the bulb foliage is where the fly lays its eggs, so I make sure there are leafy plants hiding the base of the bulb foliage. I use various broad-leaved plants like vancouveria, and even winter vegetables like lettuce and parsley. Diane Whitehead Victoria, British Columbia, Canada