Adult Recognition
FWL: 5.0-6.5 mm
Forewings are dull grayish brown with a row of black dots near the apex and termen. Male genitalia are characterized by an elongate valva with rounded cucullus. Female genitalia are characterized by rectangular lateral extensions of the sterigma with sharply pointed posterolateral projections.
Adults are similar to other species of Grapholita, including Grapholita funebrana, Grapholita libertina, Grapholita tenebrosana, and several others. A genitalic dissection may be necessary to confirm species identity, especially if individuals are recovered from sticky traps. Males of G. funebrana can be distinguished by the thornlike projection off the ventral margin of the valva, which is lacking in G. molesta. Gilligan et al. (2008) provide illustrations of male and female genitalia for many common Nearctic Grapholita.
Synthetic pheromones are not species-specific, and G. molesta lures will attract other species of Grapholita, including G. funebrana.
Larval Morphology
Last instar larvae are approximately 10-12 mm in length with a pinkish abdomen and large pale pinacula. The head and prothoracic shield are yellowish brown. The anal shield is light brown without mottling. An anal comb is present with ca. 5 teeth. Early instars are assumed to be whitish with a black head and prothoracic shield.
Larvae may appear similar to those of many other species of Grapholita and Cydia. Cydia pomonella larvae can be separated from G. molesta by the absence of an anal fork. Other species of Grapholita cannot be reliably separated from G. molesta based solely on larval morphology. Chen and Dorn (2009) provide a molecular assay to distinguish G. molesta larvae from similar species using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.
Biology
Grapholita molesta completes 3-7 annual generations; the exact number depends on temperature (latitude). In midwestern North America, adults are present from early May to late September. In southern locations, adults may be present year-round.
Females lay eggs singly on smooth surfaces of the host plant, which usually includes leaves, shoots, and twigs. Early instars tunnel into shoots or pedicels. Later instars continue feeding in shoots or tunnel into fruit. The final instar leaves the fruit or shoot and constructs a cocoon on the tree or in leaf litter. Larvae complete 4-5 instars. Overwintering occurs as a prepupa and pupation occurs in the spring for the overwintering generation.
Larval damage is characterized by dead and wilting shoots and injured fruit. Injured fruit may fall early and is more prone to secondary infection by fungus.
Host plants
Grapholita molesta is an important pest of stone-fruit crops throughout the world. Most economic damage occurs in peach and nectarine, or when other fruit crops are grown adjacent to peach. In addition to the Rosaceae, larvae have been recorded feeding on plants in several families.
| Family | Genus/species | Common name |
| Cornaceae | Cornus L. | dogwood |
| Ebenaceae | Diospyros kaki L. f. | Japanese persimmon |
| Myrtaceae | Hexachlamys edulis (O. Berg) Kausel & D. Legrand | |
| Myrtaceae | Psidium guajava L. | guava |
| Rosaceae | Chaenomeles Lindl. | flowering quince |
| Rosaceae | Crataegus L. | hawthorn |
| Rosaceae | Cydonia oblonga Mill. | quince |
| Rosaceae | Eriobotrya japonica (Thunb.) Lindl. | loquat |
| Rosaceae | Malus Mill. | apple |
| Rosaceae | Malus pumila Mill. | paradise apple |
| Rosaceae | Malus sylvestris (L.) Mill. | European crab apple |
| Rosaceae | Photinia glabra (Thunb.) Maxim. | Japanese photinia |
| Rosaceae | Prunus armeniaca L. | apricot |
| Rosaceae | Prunus avium (L.) L. | sweet cherry |
| Rosaceae | Prunus cerasus L. | sour cherry |
| Rosaceae | Prunus dulcis (Mill.) D. A. Webb | sweet almond |
| Rosaceae | Prunus ilicifolia (Nutt. ex Hook. & Arn.) D. Dietr. | hollyleaf cherry |
| Rosaceae | Prunus L. | [various] |
| Rosaceae | Prunus mume Siebold & Zucc. | Japanese apricot |
| Rosaceae | Prunus persica (L.) Batsch | peach |
| Rosaceae | Prunus salicina Lindl. | Japanese plum |
| Rosaceae | Prunus serrulata var. spontanea (Maxim.) E. H. Wilson | |
| Rosaceae | Pyracantha M. Roem. | firethorn |
| Rosaceae | Pyrus communis L. | common pear |
| Rosaceae | Pyrus L. | pear |
| Rosaceae | Pyrus pyrifolia (Burm. f.) Nakai | Chinese pear |
| Rosaceae | Rosa L. | rose |
| Sapindaceae | Litchi chinensis Sonn. | lychee |
Distribution
Grapholita molesta is thought to have originated in northwest China. The first North American records are from 1913-1915. It is currently widely distributed on all continents where stone-fruit is grown.
References
Chapman, P. J. and S. E. Lienk. 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.
Chen, M. H. and S. Dorn. 2009. Reliable and efficient discrimination of four internal fruit-feeding Cydia and Grapholita species (Lepidoptera: Tortricidae) by polymerase chain reaction-restriction fragment length polymorphism. Journal of Economic Entomology. 102: 2209-2216.
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.
Heinrich, C. 1926. Revision of the North American moths of the subfamilies Laspeyresiinae and Olethreutinae. Bulletin of the U.S. National Museum. 132: 1-216.
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.
MacKay, M. R. 1959. Larvae of the North American Olethreutidae (Lepidoptera). Canadian Entomologist Supplement 10: 1-338.
Rothschild, G. H. L. and R. A. Vickers. 1991. Biology, ecology and control of the oriental fruit moth, pp. 389-412. In: L. P. S. van der Geest, H. H. Evenhuis (eds.), Tortricid pests, their biology, natural enemies and control. Elsevier, Amsterdam, The Netherlands.
Photo Credits
Fig. 5-6: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org
