Western Colorado Insect

Native Plant Seed Production

Introduction
Lupine sp.
Scientific Name: Lupine species

Common Name:
Lupine

Plant Abbreviation:
L. sericeus - LUSE

Description:
Lupines are widely distributed throughout the US and several species are grown for reclamation, revegetation and horticultural purposes. There are many horticultural varieties of lupine available. Several pests attack lupine seed production. There are sed feeders, pod feeders, foliage feders, and sucking insects. Many are Lupinus specific, some are legume specific and some such as lygus are generalist feeders.
Lupine

Lupine Seed Fly
Scientific Name: Diptera: Tephritidae

Identification and life history of the lupine seed flies are virtually unknown. They have been collected from two sites in Gunnison County CO. Fly larvae (maggots) feed on developing seeds within apparently intact seed pods. Larvae and damage were easily found in 2006, at one site. They could not be found in 2007 at the same site. Pupae of a seed fly were found in a collection of L. sericeus from Gunnison Co. CO during the summer of 2007. This insect has the potential to significantly impact lupine seed production in some areas.
Adult Adults are unknown. Based on the size of the pupae and other known tephritid species, they should be half to 2/3 the size of a house fly. There should be black pigmentation on the wings. The pattern of the pigmentation will be an important characteristic used in identification. They will probably fly during the early stages of pod formation.  
Egg Eggs are unknown. They will probably be deposited through the skin of the developing pod where there will be only a slight oviposition scar.  
Larvae Larvae are maggots less than 1 cm in length when fully grown. They will be found feeding on lupine seeds within otherwise normal looking lupine pods. fly maggot
fly maggot
Pupae It is not known where pupation takes place. My guess would be in the soil, but puparium were found in an uncleaned seed pod collection from Gunnison Co. CO. These may have appeared when larvae pupated in the collection bag. The puparium is brown, hard shelled, oval shaped and about 5 mm in length. fly pupae

Management
The first stem in management of seed flies is to determine if they are present in the field. This must be done by monitoring seed pods when they are harvested. If you find pupae, place them in a jar or petri dish to rear out adult flies. Seed flies will have black banding on the wings. The pattern of the banding is an important characteristic to use in identification. Many seed flies are attracted to yellow sticky traps, which could be an important monitoring technique. It is critical to properly identify flies trapped on sticky traps since they are not specific to a particular species and many species of seed flies are present in the field.

If chemical control is necessary, there will be two different methods. The first would be to use a residual contact insecticide such as a pyrethroid to kill the adult flies before they lay eggs. These sprays would have to be applied at night to avoid harming pollinators. Another method would involve spring time application of a neonicitinoid systemic insecticide to the soil. This technique has been effective in controling other seed flies on composite species in UT.

This page was updated on April 26, 2014