Moths of North Carolina
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142 NC Records

Blastobasis glandulella (Riley, 1871) - Acorn Moth

Blastobasis glandulellaBlastobasis glandulellaBlastobasis glandulella
Taxonomy
Superfamily:
Gelechioidea		 Family:
Blastobasidae		Subfamily:
Blastobasinae		Tribe:
Blastobasini		P3 Number:
59a1766		 MONA Number:
1162.00
Species Status: Blastobasis is a taxonomically difficult genus, with several undescribed species in North America. There appears to be several poorly resolved species complexes within this and closely related genera. Blastobasis glandulella appears to be a member of a species complex, with western populations perhaps constituting one or more undescribed species (Landry et al., 2013; BOLD). Here we treat all of the eastern forms as B. glandulella until detailed systematic studies are completed that will help resolve these issues.
Identification
Field Guide Descriptions: Beadle and Leckie (2012); Leckie and Beadle (2018)Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Forbes (1923)Technical Description, Immature Stages: Galford (1986)                                                                                 
Adult Markings: The following is based in part on the description by Forbes (1923). The dorsum of the head and thorax are silvery gray to grayish brown. The antenna is grayish brown and deeply notched in the male. The forewing is light gray to light brown, and more or less powdered and mottled with different shades of silvery gray and light brown. The most conspicuous mark is a diffuse, pale to whitish band at about one-third the wing length. The band is usually sharply angled outward near the middle of the wing (sometimes less so), and is crisply outlined with a zone of dark brown to blackish scales on the posterior margin. These become more diffuse apically and end before reaching one-half the wing length. A small dark brown to blackish spot is often evident immediately behind the apex of the angle (chevron), but is frequently masked by the dark shading. There is a well-defined pair of small dark brown to blackish discal spots just beyond two-thirds the wing length, and a series of small dark dots on the wing tip that extends forward along the costal margin before fading out near the paired spots. In some individuals, the dark dots may be faint or completely missing. The hindwing and the fringe on both wings is light gray to grayish brown. Asaphocrita aphidiella is similar, but has more elongated, prominent palps and complex patterning on the apical third of the forewing.
Wingspan: 12-25 mm (Forbes, 1923; Landry et al. (2013)
Adult Structural Features: Landry et al. (2013) have descriptions of the male and female genitalia, and illustrations of the male genitalia.
Structural photos
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae feed internally on the seed tissue of acorns and chestnuts. Gibson (1982) and others considered this species to be a secondary invader that exploited acorns and other fruits after primary invaders such as weevils fed and left exit holes. Galford (1986), however, conducted experiments which show that the larvae can bore through germinating acorns and act as primary invaders. Adults laid eggs during the fall and spring, and larvae from the fall brood overwintered in acorns. Summer broods presumably feeding on the remnants of partially eaten or damaged acorns or chestnuts from the previous year.
Larvae ID Requirements: Identifiable from close inspection of specimens or by DNA analysis.
Distribution in North Carolina
Distribution: Blastobasis glandulella is widespread in North America and is well-established in central Europe where it has been introduced. In the West, it occurs in California, Arizona, and Colorado. Farther east, it occurs in southern Canada (Quebec; Ontario; Manitoba; Saskatchewan), and throughout most of the eastern US from Maine to Florida, and westward to Texas, Oklahoma, Kansas, and Minnesota. Populations in the West are in separate BINS (BOLD) and may constitute undescribed species. We have records from all three physiographic provinces, but the majority are from the Piedmont.
County Map: Clicking on a county returns the records for the species in that county.
Blastobasis glandulella
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 are active year-round in Florida and from March through October in other areas outside of North Carolina. As of 2021, our records are from early May through early September.
Habitats and Life History
Habitats: The larvae feed on acorns, and exploited chestnuts before the widespread loss of mature trees due to chestnut blight. Local populations are found in a variety of hardwood forests or mixed hardwood-pine forests that support the host species.
Larval Host Plants: The primary hosts are oaks, including members of both the white oak and red oak groups. In the eastern US, the larvae feed on acorns of White Oak (Quercus alba), Chestnut Oak (Q. montana), Northern Red Oak (Q. rubra), and Black Oak (Q. velutina) (Robinson et al., 2010; Gibson, 1982). Other species are undoubtedly also used. There are also reports of larvae feeding on hickory and chestnut (Craighead et al., 1950) which need confirmation. We do not have any feeding records in North Carolina. - View
Observation Methods: The adults are attracted to lights and the larvae can be found by splltting open acorns.
Wikipedia
See also Habitat Account for General Oak-Hickory Forests
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR SNR [S4S5]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species appears to be common throughout its range, particularly in the Piedmont where oaks abound.

 Photo Gallery for Blastobasis glandulella - Acorn Moth

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

Recorded by: Mark Basinger on 2025-06-02
Brunswick Co.
Comment: 		Recorded by: David George, Jeff Niznik on 2025-05-24
Richmond Co.
Comment:
Recorded by: Jim Petranka and Becky Elkin on 2025-05-23
Richmond Co.
Comment: 		Recorded by: David George, Jeff Niznik, Brian Bockhahn, Jim Petranka, John Petranka, Becky Elkin on 2025-05-09
Cumberland Co.
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Recorded by: Mark Basinger on 2025-04-25
Brunswick Co.
Comment: 		Recorded by: Dean Furbish on 2025-04-09
Wake Co.
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Recorded by: Dean Furbish on 2025-04-09
Wake Co.
Comment: 		Recorded by: Mark Basinger on 2025-03-24
Brunswick Co.
Comment:
Recorded by: John Petranka on 2024-09-22
Orange Co.
Comment: 		Recorded by: David George, Jeff Niznik on 2024-09-21
Chatham Co.
Comment:
Recorded by: Mark Basinger on 2024-09-14
Brunswick Co.
Comment: 		Recorded by: Mark Basinger on 2024-08-31
Brunswick Co.
Comment:
Recorded by: John Petranka on 2024-08-31
Orange Co.
Comment: 		Recorded by: Lenny Lampel on 2024-08-29
Union Co.
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Recorded by: John Petranka on 2024-08-22
Orange Co.
Comment: 		Recorded by: Mark Basinger on 2024-08-17
Brunswick Co.
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Recorded by: Dean Furbish, Lior S. Carlson on 2024-08-17
Johnston Co.
Comment: 		Recorded by: Jeff Niznik on 2024-08-12
Orange Co.
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Recorded by: Simpson Eason on 2024-08-07
Durham Co.
Comment: 		Recorded by: David George, Jeff Niznik, Kevin Bischof on 2024-08-07
Transylvania Co.
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Recorded by: David George, Jeff Niznik on 2024-08-06
Transylvania Co.
Comment: 		Recorded by: David George, Jeff Niznik on 2024-08-05
Transylvania Co.
Comment:
Recorded by: Jeff Niznik on 2024-07-24
Orange Co.
Comment: 		Recorded by: Ken Kneidel on 2024-06-26
Watauga Co.
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Recorded by: Owen McConnell and Simpson Eason on 2024-06-19
Graham Co.
Comment: 		Recorded by: Dean Furbish, Lior S. Carlson on 2024-06-18
Lincoln Co.
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Recorded by: Ken Kneidel on 2024-05-21
Mecklenburg Co.
Comment: 		Recorded by: Emily Stanley on 2024-05-04
Buncombe Co.
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Recorded by: Mark Basinger on 2024-04-27
Brunswick Co.
Comment: 		Recorded by: R. Newman on 2024-04-22
Carteret Co.
Comment: