Pterolonche inspersa
Grey-winged root moth
Insect: moth (Lepidoptera: Pterolonchidae)
Photos Links:    Adult    
Type of Agent: Insect: Moth (Lepidoptera: Pterolonchidae) (3)
Origin:  The original source of this species is in Austria, Greece, and  Hungary.   The native distribution are France, Spain, the former USSR, Greece, Hungary, Bulgaria, Turkey, Romania, and Italy. (1)

Life Cycle:
Over wintering: They over winter as larva. (1)
Egg Stage:   The eggs are deposited on a lower leaf surface in small groups or singly.  The eggs are oval, black, and .04 mm long and .03 mm wide.  Incubation is about 12 days. (3)
Larval Stage:  The larvae feed on the center, or cortex, of the root of the plant.  Larvae spin a silken tube to cover the area where they are feeding and to provide an exit for the emerging adult.(2)
Pupal Stage:  Pupation occurs from early to the middle of July inside the root. (1,3)
Adult Stage: The adults are in the field in late July to early August.  Mating and egg laying occur right after the larvae becomes an adult. The adults last for 15 to 16 days. (1,2)

The adult is a white to brownish grey moth measuring a 1.9 to 2.5 mm wingspan and 8 mm in length.  Their wings are narrow and have no distinct markings. (1,2,3)

Destructive stage: Larval (1)
Plant species attacked: Diffuse knapweed, (Centaurea diffusa,) spotted knapweed, (Centaurea maculosa,) and squarrose knapweed, (Centaurea squarrosa.) (1)
Site of Attack: central vascular tissue of the roots (1)
Damage to host:  The larva damages the roots by feeding on them.  The plants become shorter and produce less flowers.  The attacked roots become swollen and spongy.  The roots are then more susceptible to viral, bacterial, and fungal infections. (1,2,3)

First introduced into U.S: 1986, Idaho, Oregon, and Utah. (3)
Now established in: Oregon, but has not been recovered since 2000. (3)
Habitat: Hot, dry areas with limited vegetation.  The insect does not do well at higher elevations and habitats with rainfall. (3)
Availability: Is not yet available. (2,3)
Stages to Transfer: Adult (3)
Redistribution: No good redistribution techniques have been established yet. (3)
How to Collect: Use a sweep net when they are out on the plants.  To release the insects, simply sprinkle them from jars on the knapweed leaves, or swing your arm around with the container open to let them out. (1)

Useful Links
Literature Cited
1.  Rees, Norman, et. al., Ed., Biological Control of Weeds in the West, Western Society of Weed  Science, in Cooperation with USDA ARS, MT Dept. of Ag, and MT State Univ., Color Printers, Bozeman, MT, Feb., 1996.

2. Lang, R.F Biological Control: A Guide to Natural Enemies in North America, (online) available: , Page last modified: Feb. 9, 2000 Text last modified: April 18, 1997.

3. Story, J.M. and Coombs, E.M. "Pterolonche inspersa." Biological Control. Ed. Eric Coombs, Janet Clark, Gary Piper, and Alfred Cofrancesco Jr. Corvallis Oregon: Oregon State University Press, 2004. 221-222
Updated by: Hilary Palakovich    3/17/05
By: Traci  Henningsen       1/ 14/ 02
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