How to Manage Pests

Pests in Gardens and Landscapes

Seasonal development and life cycle—Bulb flies

The adult lays an egg in spring or summer on exposed bulbs or stems at or near the base of plants.  After 5 to 14 days, the egg hatches and a larva wriggles down into the soil or moves down along the outside of the bulb.  It feeds on the bottom of the bulb where the roots emerge then enters and feeds inside the bulb.  The larva develops through three instars over a period of 9 to 10 months.  In spring the larva pupates in a brownish case inside the bulb, or it emerges and pupates nearby in topsoil.  Pupation takes 4 to 8 weeks, after which the adult emerges, mates, and females lay eggs.  Adults live about 2 to 3 weeks.

Bulb fly life cycle
Bulb fly life cycle (by Valerie Winemiller, adult from C.F. Doucette. 1959. The Narcissus Bulb Fly. USDA Leaflet 444.)

Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2014 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /PMG/GARDEN/FLOWERS/INVERT/lcbulbfly.html revised: April 25, 2014. Contact webmaster.