Grapholita interstinctana

Type

Native

Taxonomy

Grapholita interstinctana (Clemens) (Tortricidae: Olethreutinae: Grapholitini)

Common names: clover seed caterpillar, clover head caterpillar

Synonyms: distema (Grapholitha), scitana (Dichrorampha)

Adult Recognition

FWL: 4.0-6.0 mm

Forewings are dark brown with a single pair of white dorsaldorsal:
upper, to the top, on the back
strigulae per wing and four pairs of white costal strigulaecostal strigulae:
small, usually pale, semirectangular marks along the costa
. The ocellusocellus:
forewing pattern element - an ovoid region anterior to the tornus; adult head - a simple insect "eye" located dorsal to the compound eye
is reduced to a silvery-blue bar. The male lacks a forewing costal foldforewing costal fold:
a flap or fold at the base of the forewing that contains specialized sex scales
. The hindwings are brown with a white fringe.

Male genitalia are characterized a rudimentary uncusuncus:
a sclerotized process which is fused to the posterodorsal margin of tergum IX
and by the valvaevalvae:
plural of "valva"
, which have a straight costal margincostal margin:
see costa
and a V-shaped ventralventral:
lower, to the bottom, on the under side
invagination at the neck. Female genitalia are characterized by laterallateral:
to the side
sclerotizations in the ductus bursaeductus bursae:
a membranous tube connecting the ostium bursae to the corpus bursae
and the absence of signasigna:
plural of "signum"
in the corpus bursaecorpus bursae:
a dilated membranous sac at the anterior end of the bursa copulatrix
.

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 5.0-6.0 mm in length; width of head 0.7-0.8 mm; head yellowish-brown with black pigmentation in ocellar area; prothoracic yellowish-brown with some brownish pigmentation; body pale yellow, legs concolorous; pinaculapinacula:
flattened sclerotized plates on a caterpillar that bear the setae
moderate in size, but concolorous and inconspicuous; anal fork absent; SV group on A1, 2, 7, 8, 9 typically 3:3:1(2):1:1.

Detailed figures of larval chaetotaxychaetotaxy:
the arrangement of setae (in reference to Lepidoptera larvae), often depicted on a "setal map"
are available in MacKay (1959)MacKay (1959):
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338..

Similar Species

Adults appear similar to many other species of Grapholita. In eastern North America, Grapholita fana is most similar, but the two species are easily distinguished by the larger ocellusocellus:
forewing pattern element - an ovoid region anterior to the tornus; adult head - a simple insect "eye" located dorsal to the compound eye
in G. fana. Genitalia of the two species are different: males of G. fana lack the invagination on the ventralventral:
lower, to the bottom, on the under side
surface of the valve and females possess a pair of short signasigna:
plural of "signum"
.

Biology

The following account is summarized from Wehrle (1924)Wehrle (1924):
Wehrle, L. P. 1924. The clover-seed caterpillar. Cornell University Agricultural Experiment Station Bulletin. 428. 34 pp..

Grapholita interstinctana completes 2-3 generations per year. Adults fly from late May to September.

Larvae feed on seeds in the heads of clover; usually one larva is present per flower head. Overwintering occurs as a mature larva and pupation occurs in the spring.

In the early part of the 20th century, G. interstinctana was considered a significant pest of clover (Folsom 1909Folsom 1909:
Folsom, J. W. 1909. Clover seed-caterpillar, pp. 133-137. In : The insect pests of clover and alfalfa. University of Illinois Agricultural Experiment Station Bulletin 134.). Larvae have also been reported feeding on sunflower (Asteraceae).

Host plant	Host plant family	Reference(s)
Helianthus sp.	Asteraceae	Gilligan et al. 2008Gilligan et al. 2008: Gilligan, T. M., Wright, D. J., Gibson, L. D. 2008. Olethreutine moths of the midwestern United States, an identification guide. Ohio Biological Survey, Columbus, Ohio. 334 pp.
Trifolium incarnatum	Fabaceae	MacKay 1959MacKay 1959: MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist, Supplement 10: 1-338.
Trifolium sp.	Fabaceae	Wehrle 1924Wehrle 1924: Wehrle, L. P. 1924. The clover-seed caterpillar. Cornell University Agricultural Experiment Station Bulletin. 428. 34 pp.; Heinrich 1926Heinrich 1926: Heinrich, C. 1926. Revision of the North American moths of the subfamilies Laspeyresiinae and Olethreutinae. Bulletin of the United States National Museum. 132: 1-216.