Moths of North Carolina

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Crambus praefectellus (Zincken, 1821) - Common Grass-veneer

Taxonomy

Superfamily:
Pyraloidea

Family:
Crambidae

Subfamily:
Crambinae

Tribe:
Crambini

P3 Number:
80a1565

MONA Number:
5355.00

Other Common Name:
American Common Grass-veneer

Comments: The genus Crambus includes around 155 species that are distributed globally. Some of the species are significant pests that can cause damage to agricultural crops, lawns and rangelands. This is one of 41 species in this genus that occur in North America north of Mexico (Pohl and Nanz, 2023), and one of fifteen species that occur in North Carolina.

Identification

Field Guide Descriptions: Beadle and Leckie (2012)

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

Technical Description, Adults: Fernald (1896)

Technical Description, Immature Stages: Ainslie (1923a)

Adult Markings: In this species the head, palps, and thorax are cinereus with a bronze luster (Fernald, 1896). The ground color of the forewing is golden fuscous and is overlain with a silvery white longitudinal stripe that is undivided. The stripe begins at the base of the wing and gradually widens to a point just past the middle of the wing, then gradually shortens to a sharp point just before the subterminal line. It is paralleled by a brown stripe along the costa that is nearly half as wide at the middle of the costa as the silvery stripe. The subterminal line is dark reddish-brown and v-shaped. A short, white dash is present on each side on the subterminal line along the costa. These are followed apically by a triangular reddish-brown mark with a white center and a dark brown terminal line that is most prominent on the costal half on the outer margin. A series of four or five black dots are present in the subterminal area that are separate from the terminal line by a short gap (Forbes, 1923). The fringe is pale-colored, while the hindwing varies from white to cream-colored and has a white fringe.

Crambus praefectellus is similar to C. leachellus, but the latter has a much thinner brown stripe along the costa that is less than one third as wide as the adjoining longitudinal white stripe when measured at the middle of the wing.

Wingspan: 21-25 mm (Fernald, 1896); 18-25 mm (Ainslie, 1923a).

Adult Structural Features: Ainslie (1924) has descriptions and illustrations of the male and female genitalia.

Structural photos

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

Immatures and Development: The larvae are commonly referred to as sod webworms and are known to feed on corn and other cultivated grasses, as well as pasture grasses where this and other crambids can cause significant losses (e.g., Webster, 1923). Ainslie (1923a) provides a comprehensive life history account as follows that is mostly based on observations of captive, reared animals that were fed on Kentucky Bluegrass. The females drop their dry eggs as the fly over the host plants and have an average clutch size of around 118 eggs. Hatching typically occurs 5-9 days after oviposition during the warmer months. The hatchlings feed on the leaves and make small longitudinal pits that are covered with silk and frass, but by the third instar become large enough to consume the entire leaf. They later descend to the ground and construct silk-lined burrows in the soil, with the opening near the soil surface. They then cut and drag leaves to the burrows and feed from there. Feeding occurs mostly at night, and there are typically six instars (rarely seven). The last instar abandons its burrow and builds a cocoon in the soil nearby. The cocoon is composed of silk and soil that is interwoven to form a stiff structure that is about the size of a shelled peanut. The adults emerge around 10 days later. The entire period from egg laying to adult emergence requires about two months.

Britton (1920) observed damage to seedling corn plants in Connecticut and noted that a hole had been eaten into one side of each plant at ground level or just above. The larvae lived in a case formed by soil particles webbed together. The larvae were around 12 mm long with dirty white to ash-gray bodies that were prominently marked with darker tubercles, with each body segment bearing eight tubercles. The prothoracic shield was whitish and shiny and marked with several dark gray spots, and the head shiny white and mottled dorsally with brown.

Distribution in North Carolina

Distribution: Crambus praefectellus is widely distributed across North America where it is most common in the eastern U.S. This species has been observed throughout much of southern Canada from British Columbia eastward to Nova Scotia and Prince Edward Island, and in the western U.S. mostly in relatively mesic habitats in California, Oregon, Washington, Arizona, New Mexico, Colorado and Utah. In the eastern U.S. the range extends from Maine southward to Florida, and westward to Louisiana, Arkansas, Oklahoma, Nebraska, and North Dakota. This species occurs in all three physiographic provinces in North Carolina, but is rare at higher elevation sites 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 have been observed from March through November in different areas of the range, but most commonly from May through October. As of 2023, our records range from mid-March through early-November. Populations in North Carolina appear to have two or more generations yearly.

Habitats and Life History

Habitats: This species is commonly found in early successional habitats, pasturelands, field edges, roadway corridors and residential neighborhoods that support grasses.

Larval Host Plants: The larvae feed on grasses, including young corn plants, timothy, wheat and pasture grasses where this and other crambids can cause significant losses (e.g., Ainslie, 1922, 1923a, 1924; Webster, 1923). Solis (2008) noted that they also feed on sedges, while Ainslie (1923a) reported that they will readily feed on corn, wheat, rye, oats, timothy, Kentucky Bluegrass (Poa pratensis) and Yellow Foxtail (Setaria glauca) in captivity. - View

Observation Methods: The adults are attracted to lights and the larvae can be found near the bases of grasses and cereal crops. They also can be flushed fairly easily by walking through grassy habitats.

Wikipedia

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 species is common and widespread in North Carolina and exploits weedy grasses and field crops that abound within the state.

Photo Gallery for Crambus praefectellus - Common Grass-veneer

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

	Recorded by: Jim Petranka on 2025-10-02 Madison Co. Comment:		Recorded by: Jim Petranka on 2025-09-28 Madison Co. Comment:
	Recorded by: Allison Garton on 2025-09-08 Moore Co. Comment:		Recorded by: Allison Garton on 2025-09-07 Moore Co. Comment:
	Recorded by: Allison Garton on 2025-09-03 Moore Co. Comment:		Recorded by: Allison Garton on 2025-09-03 Moore Co. Comment:
	Recorded by: Jim Petranka and Becky Elkin on 2025-07-26 Madison Co. Comment:		Recorded by: Dean Furbish on 2025-07-04 Wake Co. Comment:
	Recorded by: Jeff Niznik, David George, Larry Chen, Sarah Toner, Joye Zhou on 2025-06-20 Richmond Co. Comment:		Recorded by: Jeff Niznik, David George, Larry Chen, Sarah Toner, Joye Zhou on 2025-06-20 Richmond Co. Comment:
	Recorded by: Mark Basinger on 2025-06-19 Brunswick Co. Comment:		Recorded by: Jim Petranka on 2025-04-26 Madison Co. Comment:
	Recorded by: R. Newman on 2024-10-21 Carteret Co. Comment:		Recorded by: Mark Basinger on 2024-09-21 Buncombe Co. Comment:
	Recorded by: David George, Jeff Niznik, Kevin Bischof on 2024-08-07 Transylvania Co. Comment:		Recorded by: Jim Petranka on 2024-07-22 Madison Co. Comment:
	Recorded by: Dean Furbish, Lior S. Carlson on 2024-06-17 Lincoln Co. Comment:		Recorded by: Jeff Niznik on 2024-06-14 Scotland Co. Comment:
	Recorded by: Mark Basinger on 2024-05-12 Rowan Co. Comment:		Recorded by: Mark Basinger on 2024-05-12 Rowan Co. Comment:
	Recorded by: Jim Petranka and Becky Elkin on 2024-05-01 Madison Co. Comment:		Recorded by: David George, Stephen Dunn, Jeff Niznik on 2024-04-29 Chatham Co. Comment:
	Recorded by: Jim Petranka on 2024-04-29 Madison Co. Comment:		Recorded by: Jim Petranka on 2024-04-18 Madison Co. Comment:
	Recorded by: David George, Jeff Niznik, Rich Teper on 2024-04-17 New Hanover Co. Comment:		Recorded by: Jim Petranka on 2023-09-19 Madison Co. Comment:
	Recorded by: David George, Stephen Dunn, Jeff Niznik on 2023-09-07 Chatham Co. Comment:		Recorded by: Mark Shields on 2023-09-01 Onslow Co. Comment:
	Recorded by: Jeff Niznik on 2023-06-18 New Hanover Co. Comment:		Recorded by: David George, Jeff Niznik on 2023-06-10 Durham Co. Comment: