Narcissus bulb fly—Merodon equestris
Lesser bulb flies—Eumerus spp.
Adult bulb flies are stocky, hairy flies, blackish to dark
green with pale yellow, orange, or gray markings. Adult
bulb flies look like small bumble bees and may also resemble
other beneficial species. On warm sunny days, adults
often hover around blooming plants, where they feed on pollen
and nectar. Bulb fly larvae are plump, wrinkled, dirty
yellow, gray, white, or brownish maggots with a short brown
or blackish breathing tube at their rear. Maggots of several
species of flies infest bulbs of all types, including daffodil,
iris, lily, and tulip.
Larvae feed in bulbs, causing yellow foliage and stunted plants. If infested, large bulbs produce fewer leaves and distorted growth. Instead of a large shoot, small leaves may emerge in a ring around the central growing point that has been killed by a larva. Blooms and small bulbs often die. Narcissus bulb fly attacks healthy plants; lesser bulb flies prefer bulbs and rootstocks that are already diseased or decayed.
Prevention is the most effective bulb fly
control strategy. Purchase and plant only pest-free
bulbs. Handle bulbs carefully to avoid injury. Remove
and destroy infested bulbs and plants as soon as you find