Moths of North Carolina
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2 NC Records

Grapholita delineana Walker, 1863 - Eurasian Hemp Moth

Grapholita delineana
Taxonomy
Superfamily: Tortricoidea Family: TortricidaeSubfamily: OlethreutinaeTribe: GrapholitiniP3 Number: 51a1325 MONA Number: 3443.10
Species Status: This species can become a significant pest in commercial hemp fields where it damages stalks and consumes seeds.
Identification
Field Guide Descriptions: Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Gilligan et al. (2008)                                                                                 
Adult Markings: This species is essentially identical to Grapholita tristrigana and the following description applies to both. The palps are dull white, while the head, thorax, antennae, and ground of the forewing vary from dark brown to brownish gray. The most conspicuous mark is a large pale-yellow to off-white blotch on the middle of the dorsal margin that is divided by three brownish-black lines. The patch curves outwardly and stops near the middle of the wing where it adjoins a small bluish metallic spot. The ocellus is poorly expressed and is represented by a lead-colored bar only. A blackish spot is present at the apex, and the costa has a series of 10 or 12 closely crowded but clean-cut white costal striae. These extend from around one-fourth to the apex and alternate with blackish streaks that extend farther into the interior of the wing. Three or four of the white striae have bluish-metallic extensions that terminate before reaching the middle of the wing. The fringe is grayish and a black terminal line is present along the termen. The hindwing is concolorous with the forewing ground and has a gray to whitish fringe.

Grapholita delineana is difficult to distinguish from G. tristrigana. In the former the white stripes in the dorsal patch are sometimes narrower and distinctly separated by the darker lines, while those in G. tristrigana may be confluent. However, there is much overlap in variation between the species and the two are best separated using genitalia (Miller, 1982). Until we have a better understanding of how to distinguish these species, dissection will be required for a positive identification. Additional specimens are needed for study.
Wingspan: 11.5 mm for males; 15 mm for females (Ovsyannikova and Grichanov, 2009)
Forewing Length: 4.5-6.5 mm (Gilligan et al., 2008)
Adult Structural Features: Gilligan et al. (2008) and Gilligan and Epstein (TortAI) have illustrations of the male and female genitalia, and note that the males are distinguished by the abrupt narrowing of the aedeagus, while females have two large signa in the corpus bursae.
Adult ID Requirements: Identifiable only by close inspection of structural features or by DNA analysis.
Immatures and Development: The larvae feed on marijuana and other members on the Cannabaceae. McPartland (2002) summarized the life cycle as follows when feeding on marijuana. The hatchlings initially skeletonize leaves then after a few days bore into branches and stalks. Feeding within stalks causes the formation of fusiform-shaped galls on the stems. Two or more generations are produced each year and the late-season larvae shift to feeding on flowers and seeds, where they spin loose webs around the terminal buds and seed clusters. The larvae overwinter in cocoons either on the ground or in curled leaves or buds that are bound together with silk. They may also overwinter as pupae in stalks, roots, and stored seeds. The overwintering larvae pupate in April and the adults emerge in 2-3 weeks. The larvae vary from light yellow to bright red, are 8-12 mm in length, and have a light yellow to red head. The prothoracic shield is light yellow and transparent (Ovsyannikova and Grichanov, 2009).
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Grapholita delineana is native of East Asia, but has been introduced around the world in association with the commercial production of hemp. It was first recorded from North America in 1943 and has spread widely since then (Miller, 1982). Specimens have been documented in Ontario, Canada, and from Massachusetts westward to Iowa and Wisconsin, and southward to Kentucky, North Carolina, and Georgia.
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
Habitats and Life History
Habitats: Local populations as commonly found in open, weedy settings where either marijuana and other members on the Cannabaceae are present.
Larval Host Plants: The larvae feed on members on the Cannabaceae (McPartland, 2002; Park 1983; Robinson et al. 2010). The known hosts include marijuana or hemp (Cannabis sativa), Japanese Hops (Humulus japonicus), and Common Hops (H. lupulus). A smartweed (Polygonum) has also been reported to be a host (Robinson et al. 2010), but has not been verified by rearing and is questionable. - View
Observation Methods: The adults are attracted to lights and the larvae and stem galls can be found on the host plants.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR SNA
State Protection:
Comments: This is an introduced species in North America and does not merit protection.

 Photo Gallery for Grapholita delineana - Eurasian Hemp Moth

Photos: 1

Recorded by: J.B. Sullivan on 2020-10-13
Scotland Co.
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