Moths of North Carolina
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9 NC Records

Rhopobota naevana (Hübner, 1814) - Holly Tortrix Moth

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Taxonomy
Superfamily: Tortricoidea Family: TortricidaeSubfamily: OlethreutinaeTribe: EucosminiP3 Number: 621188.00 MONA Number: 3276.00
Comments: The genus Rhopobota consists of eight recognized species that occur worldwide, with only three species occurring in North America. The forewing of all three species has a distinctly pointed aspect due to emargination of the termen just below the apex.
Identification
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Kearfott (1907a)                                                                                 
Adult Markings: The following is based in part on the description by Kearfott (1907a). The head is dull gray and shaded with brown above the eyes. The palps are dark gray on the outside and the antenna dull fuscous. The thorax varies from dull gray to brownish. The forewing ground color is grayish to grayish brown with darker brownish speckling and is overlain with two dark brown fascia. The first is outwardly angulated and begins near the middle of the inner margin. It typically begins as a broad band on the dorsal half and narrows towards the costa. The second is similar and at around three-fourths where it extends from before the anal angle to the middle of the wing before narrowing and projecting basally towards the costa. The interfascial area between the two is often noticeably lighter than the general ground color. The costa is marked with a series of faint whitish strigulae that are intermixed with brown dots or streaks. The dark streaks become more pronounced on the apical half and end before a dark apical spot that is hook-shaped outwardly. The ocellus is poorly defined and consists of a grayish region that covers the outer third of the wing. It is slightly strigulated with vertical rows of brown scales. The fringe on the forewing is dull fuscous, and the hindwing is smoky brown and somewhat darker toward the apex.

This species is variable and specimens often deviate from the description above (Kearfott, 1907a). In particular, specimens often have patches of heavy black dusting on the forewing and may have a well-formed basal patch. Some forms superficially resemble both R. finitimana and R. dietziana and genitalia may be needed in some cases to separate the species. Rhopobota finitimana has a solid basal patch and a brown head and scape, while R. dietziana has whitish coloration on the scape and head. Both species tend to have a lighter interfacial area than R. naevana, which has a more drab overall appearance.
Wingspan: 13.5 to 15 mm (Kearfott, 1907a) as Epinotia ilicifoliana.
Adult Structural Features: Gilligan et al. (2008) has illustrations of the male and female genitalia. In the males, the flattened dorsolateral projections of the uncus are narrow basally but distally expanded into semiretangular lobes, while the socii are long, upturned, and distally fused. The valva has a fingerlike clasper on the proximal margin of the medial surface and a line of stout setae along the ventral margin of the neck. The sclerotization of the corpus bursae consists of two dorsolateral patches that are joined medially by a distinct arch. The size and shape of the dorsolateral projections of the uncus are useful for separating our three species.
Structural photos
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae are polyphagous but appear to prefer deciduous hollies and cranberries in the eastern US. Kearfott (1907a) reported that the larvae bind the young leaves and twigs of deciduous hollies together with webbing and feed from within. He noted that as many as 100 or so webs could be found on a single large holly bush in New Jersey. At his study site the larval period lasted about a month and the final instar pupated in a tight, dense cocoon that was spun in debris or frequently in a small leaf flap that was cut out and folded under. The adults emerged 2-3 weeks after the final instar pupated. The mature larvae reached about 12 mm in length and were dull yellow with the head, prothoracic shield, and legs black and the anal shield green.

Rhopobota naevana can become a significant pest where cranberries are grown commercially. Sylvia and Averill (2005) provide a summary of the life cycle as follows. Eggs that overwinter hatch in the spring close to the time when the plants are breaking dormancy. The larvae web together leaves -- and later adjoining shoots -- to create a web and feed from within. The time from hatching to the emergence of adults is around 4-5 weeks for the first generation. Most eggs that are laid by the emerging adults hatch to produce a second generation, but a small percentage enter diapause and hatch the following spring. Females deposit their eggs singly on the undersides of leaves and the larvae are easily recognized by their jet-black head capsules. Local populations typically have two generations per year, but occasionally produce a partial or complete third generation in favorable years.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Rhopobota naevana appears to be Holarctic where it occurs in Canada, Europe, Japan, Pakistan, and the US. It was probably introduced into western North America in the early 1900's (Gilligan et al., 2020). In eastern North America it occurs in the New England states and adjoining areas of Canada southward to South Carolina and westward to Kentucky and Illinois. As of 2022, our records are from the Coastal Plain and 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)

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Immature 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: Local populations are typically bivoltine, with the adults flying from May through September in different areas of the range. As of 2022, our records extend from late May through mid-July.
Habitats and Life History
Habitats: Local populations occur in a diverse array of communities that support the host plants, particularly blueberries in North Carolina. Examples of the diversity of communities that are used in North Carolina include maritime communities on barrier islands, Longleaf Pine communities in the Sandhills, and fens, heath thickets, and northern hardwood forests in the Blue Ridge.
Larval Host Plants: The common name 'Holly Tortrix Moth' is a bit of a misnomer given that the larvae are polyphagous and feed on a variety of trees and shrubs (Kearfott, 1907a; Pohl et al., 2005; Robinson et al., 2010). However, it commonly use hollies and cranberries in the US, and can become a pest in commercial cranberry operations. The known genera that serve as hosts around the world including Ilex, Crataegus, Fraxinus, Prunus, Pyrus, Sorbus, Spiraea, Syringa, and Vaccinium. - View
Observation Methods: The adults are mostly diurnally active (Sylvia and Averill, 2005), but occasionally appear at lights. The nests of webbed leaves and stems can be found on deciduous hollies, cranberries, and other host plants.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR[S3-S4]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species is diurnally active and has likely been undersampled because its daily activity typically stops at dusk. We need additional information on its distribution and abundance to assess its conservation status within the state.