Grapholita delineana

Status

ADVENTIVE

PORT INTERCEPT | DOMESTIC SURVEY

Taxonomy

Grapholita delineana (Walker) (Tortricidae: Olethreutinae: Grapholitini)

Common names: Eurasian hemp borer

Synonyms: apicatana (Grapholita), mundana (Grapholitha), quadristriana (Laspeyresia), sinana (Grapholitha), terstrigana (Grapholitha), tetragrammana (Grapholitha)

Adult Recognition

FWL: 4.5–6.5 mm

Adults are dark brown with two pairs of white dorsal strigulae and multiple pairs of costal strigulae on each forewing. Males lack a forewing costal fold. Hindwings are dark brown with a white fringe.

Male genitalia are characterized by the absence of an uncus, valvae with a well-developed cucullus, and an aedeagus that narrows abruptly. Female genitalia are characterized by a short ductus bursae and two horn-like signa in the corpus bursae.

Larval Morphology

The following account is summarized from Komai (1999)Komai (1999):
Komai, F. 1999. A taxonomic review of the genus Grapholita and allied genera (Lepidoptera: Tortricidae) in the Palaearctic region. Entomologica Scandinavica Supplement 55. 226 pp..

Larvae are similar to those of other Grapholita. Head, prothoracic shield yellow, yellowish brown, or brown; body whitish yellow; anal fork absent.

Detailed figures of larval chaetotaxy are available in Komai (1999)Komai (1999):
Komai, F. 1999. A taxonomic review of the genus Grapholita and allied genera (Lepidoptera: Tortricidae) in the Palaearctic region. Entomologica Scandinavica Supplement 55. 226 pp..

Similar Species

Wing pattern is similar to other Grapholita, especially G. tristrigana in eastern North America. The dorsal strigulae in G. delineana are usually narrow and distinctly separated, while those in G. tristrigana may be confluent. The two species can be separated by genitalia: in G. tristrigana the male aedeagus tapers evenly, and females lack a signum in the corpus bursae.

Distribution

Grapholita delineana is a native of East Asia that has spread into Europe, Asia Minor, Transcausasia, and North America along with the commercial production of hemp. It was first recorded from North America in 1943 (Miller 1982Miller 1982:
Miller, W. E. 1982. Grapholita delineana (Walker), a Eurasian hemp moth, discovered in North America. Annals of the Entomological Society of America. 75: 184-186.) and it is currently distributed from New York west to Minnesota and south to Missouri.

Biology

The following account is summarized from Miller (1982)Miller (1982):
Miller, W. E. 1982. Grapholita delineana (Walker), a Eurasian hemp moth, discovered in North America. Annals of the Entomological Society of America. 75: 184-186..

Grapholita delineana completes 2–3 generations per year. Adults are present in mid May to August in North America.

Females lay eggs on the leaves and stems of the host plant. Larvae feed in the stems, on developing seeds, and also on flowers. Infested plants show a swelling in the stem and possibly and entrance hole with extruded frass. Pupation occurs in the soil.

Larvae can be pests on marijuana, hemp, and hops (Cannabaceae) and have also been recorded on knotweed (Polygonaceae).

Plant Associations

View full screen host table here

Links

Additional photos and a distribution map of this species in North America are available at Moth Photographers Group.