Moths of North Carolina
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46 NC Records

Polygrammodes flavidalis (Guenée, 1854) - Ironweed Root Moth

Taxonomy
Superfamily: Pyraloidea Family: CrambidaeSubfamily: PyraustinaeTribe: SpilomeliniP3 Number: 801334.00 MONA Number: 5228.00
Identification
Field Guide Descriptions: Covell (1984); Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Forbes (1923)                                                                                 
Adult Markings: This is a rather distinctive species that has a pale-yellow ground color on the head, thorax, abdomen, and forewing. The forewing ground tends to shade more into a cream color towards the apex, and the costa is commonly shaded with reddish-brown on the basal two-thirds. The marks on the forewing are all well-defined and reddish brown, with blackish scales sometimes intermixed. The forewing of fresh specimens has two spots near the base, followed by a small orbicular spot below the costa and a reniform that is linear. The transverse lines are all irregularly wavy and consist of an antemedial that extends the full width of the wing at about one-fourth the wing length, a median that extends from the inner margin to near the reniform line, and the postmedial that is often broken, but usually extends the entire width of the wing from the costa to the tornus. The subterminal area has a linear sequence of six spots or u-shaped marks that parallel the termen and are sometimes connected to form a complete line. The fringe is concolorous with the adjoining ground color. The hindwing ground is concolorous with that of the forewing and has three transverse lines that resemble those on the forewing. The abdomen of unworn specimens also has pairs of reddish-brown spots on the basal segments.
Wingspan: 28-35 mm (Forbes, 1923).
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: Forbes (1923) noted that the larvae are root borers in ironweeds (Vernonia) and usually pupate in stubs of plants of the previous year in June. Aaron Brees (BugGuide) successfully reared an adult from a larva that was boring in the roots of Smooth Ironweed (V. fasciculata). The larva was grub-like with a white, cylindrical body and an amber-colored head.
Distribution in North Carolina
Distribution: Polygrammodes flavidalis is found in the eastern U.S. and Ontario from Massachusetts westward through the Great Lakes states to Minnesota, and southward to Oklahoma, eastern Texas, the Gulf Coast states, Florida and Georgia. As of 2023, our records are from the lower elevations in the Blue Ridge eastward to the eastern Piedmont, with one isolated record from the Coastal Plain.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Flight Comments: The adults have been observed from March through October in different areas of the range, with the peak season from June through August. As of 2023, our records extend from late-May through mid-August.
Habitats and Life History
Habitats: Local populations are generally associated with fragmented landscapes that support ironweeds. Typical habitats include mesic to wet areas of pastures, old fields, wildlife plots, roadways, powerline corridors, and streambanks.
Larval Host Plants: The larvae feed on the roots of Ironweed, including Smooth Ironweed (Vernonia fasciculata; Forbes, 1923; Covell, 1984; Beadle and Leckie, 2012; Robinson et al., 2010; BugGuide). - View
Observation Methods: The adults are attracted to lights.
Wikipedia
See also Habitat Account for General Forests and Fields
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR S3S4
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species is patchily distributed across the landscape wherever the host species occur. It appears to be reasonably secure since the hosts are often associated with disturbed habitats.

 Photo Gallery for Polygrammodes flavidalis - Ironweed Root Moth

Photos: 20

Recorded by: Jim Petranka, Becky Elkin and Tony McBride on 2023-07-23
Madison Co.
Comment: 		Recorded by: K. Bischof on 2023-07-23
Transylvania Co.
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Recorded by: Emily Stanley on 2023-07-17
Yancey Co.
Comment: 		Recorded by: Jim Petranka on 2023-06-21
Madison Co.
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Recorded by: K. Bischof on 2023-06-14
Transylvania Co.
Comment: 		Recorded by: Simpson Eason on 2022-08-22
Durham Co.
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Recorded by: Gary Maness on 2022-07-07
Guilford Co.
Comment: 		Recorded by: Richard Teper on 2022-06-16
Macon Co.
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Recorded by: Vin Stanton on 2021-07-31
Buncombe Co.
Comment: 		Recorded by: Jim Petranka on 2021-07-16
Madison Co.
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Recorded by: Jim Petranka on 2021-06-29
Madison Co.
Comment: 		Recorded by: Jim Petranka on 2021-06-18
Madison Co.
Comment:
Recorded by: Jim Petranka and Becky Elkin on 2020-08-15
Madison Co.
Comment: 		Recorded by: Owen McConnell on 2020-07-04
Durham Co.
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Recorded by: Jim Petranka and Becky Elkin on 2019-07-17
Madison Co.
Comment: 		Recorded by: Jim Petranka and Becky Elkin on 2019-06-01
Madison Co.
Comment:
Recorded by: David L. Heavner on 2018-08-09
Buncombe Co.
Comment: 		Recorded by: Jim Petranka and Becky Elkin on 2018-07-06
Madison Co.
Comment:
Recorded by: Jim Petranka and Becky Elkin on 2018-06-22
Madison Co.
Comment: 		Recorded by: Jim Petranka and Becky Elkin on 2018-05-30
Madison Co.
Comment: