Moths of North Carolina

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Parapediasia teterrellus (Zincken, 1821) - Bluegrass Webworm Moth

Taxonomy

Superfamily:
Pyraloidea

Family:
Crambidae

Subfamily:
Crambinae

Tribe:
Crambini

P3 Number:
80a1529

MONA Number:
5451.00

MONA Synonym:
Parapediasia teterrella

Identification

Field Guide Descriptions: Beadle and Leckie (2012)

Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLD

Technical Description, Adults: Ainslie (1930)

Technical Description, Immature Stages: Ainslie (1930)

Adult Markings: The following is based in part on the description by Ainslie (1930). The palps and head are whitish above, while the lower sides of the palps, the thorax, and the abdomen vary from pale ashy-gray to light brown. The forewing typically has an overall ashy-gray to yellowish-brown color, with the dorsal half before the median line having a darker wash, particularly near the center of the wing. The median line is orangish and often obscure. It runs obliquely outward from just beyond the middle of the costa for about one-third of its length, then angles back and runs to the inner margin. The subterminal line is orange and is edged outwardly with a grayish-white line of equal width. It also has an outward angle at about one-third of its length and continues on to the inner margin. The region between the median and subterminal lines are more or less marked between the lighter veins with orange scales that are weakly edged with black. The terminal line is represented by seven black dots, and the space between it and the subterminal line is covered with white scales tipped with black, which produces a grainy appearance that is very characteristic of this species. The fringe is cinereus with a golden tinge, and the hindwing is uniformly pale ashy gray with a white fringe.

This species is not conspicuously marked and the general color can vary from a light fawn to a dark earthy brown. However, the grainy pattern of the subterminal area is characteristic of this species. Parapediasia decorellus is similar, but is more boldly patterned, has a double subterminal line, and has the subterminal region filled with yellowish-orange coloration.

Wingspan: 15-21 mm (Ainslie, 1924)

Adult Structural Features: Ainslie (1924) has a description of the male genitalia.

Structural photos

Adult ID Requirements: Identifiable from good quality photos of unworn specimens.

Immatures and Development: The following life history account is from Ainslie (1930), who made observations in the field, and reared larvae and adults on Kentucky Bluegrass in Tennessee, both in the lab and in outdoor enclosures. The females lay their dry eggs either when at rest, or more commonly while fluttering about over the host plants in late-afternoon or shortly after dark. Most females lay 200-250 eggs or so, with a few producing more than 500. The eggs when first laid are pure white, but turn to pale lemon yellow after three days. Hatching takes around 5-7 days depending on ambient temperatures. The hatchlings move about quickly then settle down near the bases of the grasses where they create silk tubes by webbing together soil particles and sometimes opposing grass blades. The tubes serve as retreats and are later augmented with frass. The young larvae skeletonize the grass blades between the tougher veins beneath a silk webbing covered with frass, while the older larvae cut the blades at their bases and consume the entire blade. The older larvae construct rather flimsy retreats from silk and soil particles that resemble tunnels with bare ground floors. These are around 10-40 mm long and radiate away from the grass stalk along the surface of the ground. They may leave the tunnels to feed directly on the plant, or cut blades and drag them to the tunnel to consume. The older larvae also construct more stout silk-lined tubes that are 10-30 mm long and run perpendicular to the ground. They appear to function as more permanent refuges and as a site for ecdysis. The larval stage has from 7-10 instars prior to pupation. The later instars have a dusky yellow head with an indefinite pattern of darker areas, along with a dusky yellow body with numerous, very large pinacula. When fully grown the larva abandons its feeding burrow and constructs a cocoon in the earth nearby. The oval cocoon is lined loosely with gray silk and stands roughly vertically in the ground. It measures about 14 mm long and 6 mm wide, including the soil that is attached to the outside. The adults emerge around 5-15 days after the larvae pupate. Ainslie (1930) noted that there were three overlapping generations in eastern Tennessee, with larvae from the last breeding bout overwintering and resuming growth the following spring.

Distribution in North Carolina

Distribution: Parapediasia teterrellus is a wide-ranging species that has been found in every state of the conterminous U.S. except for Washington, Idaho, Montana, Wyoming and the Dakotas. It is most common in the eastern U.S. and has also been documented in Ontario, Nova Scotia and Alaska. This species occurs statewide in North Carolina, except in the higher elevations in the Blue Ridge.

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 fly year-round in Florida and Texas, and mostly from June through September in the northernmost areas of the range. As of 2023, our records extend from mid-April through early-November. Local population in North Carolina appear to have two or three overlapping generations per year.

Habitats and Life History

Habitats: The adults are typically found in suburban landscapes, as well as meadows, pastures, roadways, utility corridors and other early successional or disturbed habits.

Larval Host Plants: Ainslie (1930) noted that the larvae often injure grasses in pastures, meadows and lawns, particularly during droughts in limestone regions in Kentucky and Tennessee where Kentucky Bluegrass is common. He successfully reared the larvae and adults wholly or in part on Orchard Grass (Dactylis glomerata), Hairy Crabgrass (Digitaria sanguinalis), Common Timothy (Phleum pratense) Kentucky Bluegrass (Poa pratensis), Yellow Bristlegrass (Setaria pumila) and Johnson Grass (Sorghum halepense), as well as wheat, rye, and both the leaves and fresh silk of corn. Among these, Kentucky Bluegrass was the most preferred food, and was also widely used in the wild. Both mosses and Cowpea leaves (Vigna sp.) were rejected, which suggest that this species is a true grass specialist. Gao et al. (2013) also reported that this species has become a major pest on Bermuda Grass (Cynodon dactylon) in lawns in East Asia where it is an invasive species. - View

Observation Methods: The adults come to both building and UV lights.

Wikipedia

See also Habitat Account for General Fields, Gardens, and Ruderal Habitats

Status in North Carolina

Natural Heritage Program Status:

Natural Heritage Program Ranks: GNR S5

State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.

Comments: This is a widespread and common species that is secure in North Carolina.

Photo Gallery for Parapediasia teterrellus - Bluegrass Webworm Moth

217 photos are available. Only the most recent 30 are shown.

	Recorded by: Marilyn Westphal on 2025-08-30 Henderson Co. Comment:		Recorded by: Dean Furbish on 2025-08-16 Orange Co. Comment:
	Recorded by: Mark Basinger on 2025-08-13 Ashe Co. Comment:		Recorded by: Dean Furbish, Lior S. Carlson, Randy Emmitt on 2025-08-12 Alamance Co. Comment:
	Recorded by: Jim Petranka, Becky Elkin and Marilyn Westphal. on 2025-08-09 Henderson Co. Comment:		Recorded by: Mark Basinger on 2025-07-28 Wilson Co. Comment:
	Recorded by: Dean Furbish on 2025-07-04 Wake Co. Comment:		Recorded by: Dean Furbish on 2025-07-03 Wake Co. Comment:
	Recorded by: Dean Furbish on 2025-07-02 Wake Co. Comment:		Recorded by: Dean Furbish on 2025-06-30 Wake Co. Comment:
	Recorded by: Simpson Eason on 2025-06-27 Durham Co. Comment:		Recorded by: Melody McMichael on 2025-06-26 Forsyth Co. Comment:
	Recorded by: Allison Garton on 2025-06-21 Moore Co. Comment:		Recorded by: Mark Basinger on 2025-06-21 Wilson Co. Comment:
	Recorded by: Dean Furbish, Lior S. Carlson on 2025-06-18 Alamance Co. Comment:		Recorded by: B. Bockhahn on 2025-06-03 Currituck Co. Comment:
	Recorded by: David George on 2025-05-17 Durham Co. Comment:		Recorded by: Chuck Smith on 2025-05-16 Davidson Co. Comment:
	Recorded by: David George, Jeff Niznik, Brian Bockhahn on 2025-05-09 Cumberland Co. Comment:		Recorded by: Jim Petranka, John Petranka and Becky Elkin on 2025-05-08 Harnett Co. Comment:
	Recorded by: Mark Basinger on 2025-05-05 Wilson Co. Comment:		Recorded by: Jim Petranka on 2025-05-01 Madison Co. Comment:
	Recorded by: John Petranka and Sally Gewalt on 2025-04-29 Warren Co. Comment:		Recorded by: David George, Bonnie Eamick on 2025-04-25 Wake Co. Comment:
	Recorded by: Dean Furbish on 2025-04-17 Wake Co. Comment:		Recorded by: Dean Furbish on 2024-09-23 Wake Co. Comment:
	Recorded by: John Petranka on 2024-09-14 Orange Co. Comment:		Recorded by: Jim Petranka on 2024-09-11 Madison Co. Comment:
	Recorded by: Jeff Niznik, David George on 2024-09-07 Alamance Co. Comment:		Recorded by: John Petranka on 2024-09-06 Orange Co. Comment: