Aspila prunivora

Status

NATIVE

DOMESTIC SURVEY

Taxonomy

Aspila prunivora (Walsingham) (Tortricidae: Olethreutinae: Grapholitini)

Common names: lesser apple worm

Note: Aspila prunivora was formerly known as Grapholita prunivora until recently (Hu et al. 2023Hu et al. 2023:
Hu, G.-L., Brown, J. W., Heikkilä, M., Aarvik, L., Mutanen, M. 2023. Molecular phylogeny, divergence time, biogeography and trends in host plant usage in the agriculturally important tortricid tribe Grapholitini (Lepidoptera: Tortricidae: Olethreutinae). Cladistics. 39(5): 359–381.). 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. provides a taxonomic history for the Grapholitini.

Adult Recognition

FWL: 4.0–5.5 mm

Forewing pattern is distinctive with pale-yellow costal strigulae, silvery striae, a line of yellow scales preceding the black terminal line, and a well-developed ocellus with 3–4 black dashes. Males lack a forewing costal fold. The hindwing is dark brown, but lighter basally.

Male genitalia are characterized by the absence of an uncus and valva with an angular apex and evenly rounded anal angle of the cucullus. Female genitalia are characterized by a ringlike sterigma with weakly sclerotized lateral extensions and two, long, slender, thorn-like signa in the corpus bursae.

Larval Morphology

The following account is summarized from MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..

Mature larva approximately 7.5–9.5 mm in length; width of head 0.7–0.8 mm; head yellowish brown with darker mottling; prothoracic shield and anal shield brown, the prothoracic shield may have some dark posterolateral markings; body pale reddish, pinacula moderately large; anal fork present with 4–6 teeth.

Larval chaeototaxy is described but not figured in MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..

Similar Species

Fresh specimens of A. prunivora are unlikely to be confused with any other species in North America; worn specimens can be dissected to confirm identity.

Larvae may appear similar to those of many other species of Aspila, Grapholita and Cydia. Cydia pomonella larvae can be separated from A. prunivora by the absence of an anal fork and their larger size. Larvae of A. molesta are similar but generally larger. Larvae of A. packardi and A. prunivora are very similar, although the pinacula on the 8th and 9th abdominal segment are more prominent in A. packardi, and the abdomen of A. prunivora is more reddish, especially in preserved specimens.

Distribution

Aspila prunivora is found throughout southern Canada and the continental United States but is more common in the east. It is noticeably absent from Florida.

Biology

The following account is summarized from Chapman and Lienk (1971)Chapman and Lienk (1971):
Chapman, P. J., Lienk, S. E. 1971. Tortricid fauna of apple in New York (Lepidoptera: Tortricidae); including an account of apple's occurrence in the state, especially as a naturalized plant. Spec. Publ. Geneva, NY: New York State Agricultural Experiment Station. 122 pp. and Weires and Riedel (1991)Weires and Riedel (1991):
Weires, R., Riedel, H. 1991. Other tortricids on pome and stone fruits, North American species, pp. 313-434. In : van der Geest, L. P. S., Evenhuis, H. H. (eds.), Tortricid pests, their biology, natural enemies and control. Elsevier, Amsterdam, The Netherlands..

Aspila prunivora completes two annual generations over much of its range. Adults are present in May to June and again in August.

Females lay eggs singly on young fruits or on the upper surface of leaves. Larvae tunnel into the fruit at the calyx end and feed inside. In apple (Malus sp.), larvae may feed directly under the skin of the fruit, creating a blotchy mine. Overwintering occurs as a mature larva and pupation occurs in the spring.

In addition to feeding on various stone-fruits, larvae of A. prunivora have also been recorded feeding inside galls.

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.