Adult Recognition
FWL: 4.5-6.5 mm
Adults are dark brown with two pair of white dorsal strigulae on each forewing. Hindwings are dark brown. Male genitalia are characterized by an aedeagus that narrows abruptly. Female genitalia are characterized by two signa in the corpus bursae.
Wing pattern is similar to other Grapholita, especially Grapholita 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.
Larval Morphology
Larvae are similar to those of other Grapholita. An anal comb is absent. Komai (1999) provides a complete setal map.
Biology
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.
Host plants
Larvae can be pests on marijuana or hop (Cannabaceae) and have also been recorded on knotweed (Polygonaceae).
| Family | Genus/species | Common name |
| Cannabaceae | Cannabis sativa L. | marijuana |
| Cannabaceae | Humulus japonicus Siebold & Zucc. | Japanese hop |
| Cannabaceae | Humulus lupulus L. | common hop |
| Polygonaceae | Polygonum L. | knotweed |
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 and it is currently distributed from New York west to Minnesota and south to Missouri.
References
Gilligan, T. M., D. J. Wright and L. D. Gibson. 2008. Olethreutine moths of the midwestern United States, an identification guide. Ohio Biological Survey, Columbus, Ohio. 334 pp.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.
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.
Razowski, J. 2003. Tortricidae of Europe, Vol. 2, Olethreutinae. Frantisek Slamka, Slovakia. 301 pp.
