Females lay their eggs singly or in small masses of 2 to 40. More than 100 eggs have been found around one bulb. The eggs hatch in 5 to 10 days. Newly hatched maggots emerge from the pointed end of the egg. The tiny maggots usually attack the base of the bulb although sometimes only the upper portion of the bulb is infested.
Infested bulbs begin to decay and the interior of the bulb fills with a semiliquid mass.
Although the maggots can successfully attack a healthy bulb, the maggots cannot complete their evelopment in the absence of certain decay organisms. After about 30 days, the maggots mature and some of them crawl to the surface where they pupate inside the last larval skin. One to 4 weeks later, adult flies emerge from the puparia. If a source of nectar is available and temperatures are not extreme, some of the lesser bulb flies may live up to 36 days. If the narcissus are planted as winter annuals and the bulb discarded after blooming in the spring, there will be no problem with lesser bulb fly maggot damage as the flies oviposit only during the warm growing season.