Moths of North Carolina
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6 NC Records

Crambus leachellus (Zincken, 1818) - Leach's Grass-veneer Moth

Superfamily: Pyraloidea Family: CrambidaeSubfamily: CrambinaeTribe: CrambiniP3 Number: 800945.00 MONA Number: 5357.00
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.
Field Guide Descriptions: Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Immature Stages: Felt (1894).                                                                                 
Adult Markings: In this species the head and thorax are brassy brown and the sides of the palps are ashy gray. The ground color of the forewing is golden fuscous. The most conspicuous mark is a broad, silvery white, longitudinal stripe that extends from the wing base before bending inward and tapering to a sharp point just before the subterminal line (Fernald, 1896). The stripe is undivided and quite broad. It is separated from the costa by a brown border on the distal half of the wing, but touches the costa on the basal half. The subterminal line runs obliquely from the costa toward the outer margin, then curves to form a rounded angle of approximately 90 degrees and runs parallel to the outer margin to the inner margin. Between the terminal, tapering portion of the longitudinal stripe and the costa there is a small, spindle-shaped white dash that can vary from very small to large enough to join the stripe. There often are a few indistinct dark lines between the dorsal edge of the stripe and the submarginal line, and a well-defined, diagonal, white costal streak just before the subterminal line. The apical area is white and has a narrow, dark brown, triangular patch that connects basally with a curved dark line that runs to the costa beyond the submarginal line. The area below the apical area and between the subterminal line and outer margin is usually slightly more grayish than the ground color of the wing, and has four or five narrow black dashes. A narrow, darker brown marginal line is present and is most distinct below the apex. The forewing fringe is semi-lustrous, brownish to brownish-white, while the hindwing is whitish with a white fringe.

Crambus ainslieellus is very similar to C. leachellus in coloration and patterning. In C. ainslieellus the broad stripe is separated from the costa by a thin brown line along its entire length, while in C. leachellus the stripe touches the costa along the basal half of the wing so that the brown line is restricted to the apical half. These species are easily distinguished based on their genitalia (Klots, 1942). Crambus praefectellus is also similar, but has a narrower longitudinal stripe, with the brown area between the stripe and the costa noticeably wider and extending along the entire length of the costa except for the subapical region.
Wingspan: 24-30 mm (Fernald, 1896); 21-32 mm (Ainslie, 1924).
Adult Structural Features: Ainslie (1924) has a description of the male genitalia.
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: The larvae are known to feed on cultivated grasses and pasture grasses where this and other crambids can cause significant losses (e.g., Webster, 1923). Felt (1894) provided a comprehensive life history account as follows. The females presumably drop their dry eggs as the fly over the host plants as seen in other sod webworms, but this was not directly observed. The eggs are initially white, but turn scarlet after about a day. They then then to geranium red a day later and remain that way thereafter. Hatching takes around 10 days in captivity and the hatchlings feed on grass blades beneath thin shelters made of silk and frass. As they age, they descend to the ground and construct cylindrical silk-lined nests that are strengthened with chewed bits of grass at the base of the stalk. The nests commonly extend into the soil for 12-13 mm or so. The larvae then cut and drag leaves to the burrows and feed from there for the rest of the larval period. With time, the nest is either expanded or the larva abandons its nest and creates a new one that accommodates its larger size. The last-instar eventually constructs a winter hibernaculum, with the outside covered with bits of grass and soil and the inside smoothly lined with silk. The larva overwinters in its hibernaculum and presumably pupates sometime during the following spring or summer. Felt (1894) did not make any direct observations concerning adult emergence. Older larvae that were about a month old were 15 mm long with a yellowish head with irregular markings. The body was brown with large blackish pinacula. At six weeks, the larvae reached 3 cm and were notably stout, but were otherwise similar to the one-month old larvae.
Distribution in North Carolina
Distribution: Crambus leachellus has a large range that encompasses most of the conterminous U.S., Alaska, and much of southern Canada from the Northwest Territories and British Columbia eastward to Newfoundland, New Brunswick, and Nova Scotia. In the U.S. the range includes most of the eastern and central U.S. from Maine southward to Florida, and westward to Texas, New Mexico, Colorado and Wyoming. Specimens have also been observed from southern California northward to Washington and western Montana. As of 2023, we have only a few records from the Sandhills and nearby areas in the southern Piedmont.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ‚Č• 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 or nearly so in southern locales such as Florida and Texas, and from June through October in Canada and other northern regions of the range. As of 2023, our limited records range from late-September through mid-October, which is consistent with Heinrichs and Matheny's (1970) observations in Knoxville, Tennessee. Local populations in North Carolina are univoltine.
Habitats and Life History
Habitats: Our records are from both xeric communities in the Sandhills and more mesic commnities in the Piedmont, including a residential neighborhood.
Larval Host Plants: The larvae feed on grasses and can be a pest in lawns, golf courses, pastures and corn fields (Felt, 1894; Ainslie, 1924; McDaniel et al., 1984), but details about the specific hosts are lacking. McDaniel et al. (1984) collected adults where traps were set up in areas with turf grasses, including blue grass and Kentucky-31 fescue. - View
Observation Methods: The adults are attracted to lights.
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 wide-ranging species appears to be relatively uncommon in North Carolina, but this may in part be due to its brief flight period.

 Photo Gallery for Crambus leachellus - Leach's Grass-veneer Moth

Photos: 2

Recorded by: Lenny Lampel on 2017-10-19
Mecklenburg Co.
Recorded by: Darryl Willis on 2012-10-15
Cabarrus Co.