Adult Recognition
FWL: 8.0-11.0 mm
This is the only tortricid species with an unmarked, uniformly green forewing. The exact color varies from bright green to dull pale green, and some individuals have dull-yellow forewings, a condition that can also be caused by exposure of specimens to various killing agents and prolonged sunlight.
Male genitalia are distinguished by the following characters: uncus absent; socii large; valva sub-rectangular with well developed sacculus. Female genitalia are charaterized by broad papillae anales with a patch of flat-headed setae, short apophyses, a long ductus bursae, and a small signum in the corpus bursae.
Adults of this species are unlikely to be confused with any other tortricid. In Europe, T. viridana is similar both in size and coloration to Earias clorana (Noctuidae: Nolinae).
Larval Morphology
Late instar larvae are appoximately 15-20 mm long with a green to gray abdomen. The head varies in color from brown to black and the prothoracic shield varies from near-translucent to black. Darkened pinacula, which are more prominent near the anterior end of the abdomen and on the thorax, serve to separate this species from many North American Tortricidae larvae. Other diagnostic characters include black thoracic legs and an anal comb with eight teeth.
Biology
Tortrix viridana completes a single generation per year. Adults are present from May until early July over most of its range.
Females lay eggs during June and July in the crown of the host tree; eggs are laid in pairs for a total of 50-60 per female. The eggs overwinter and larvae hatch the following April and May. First instar larvae feed on open buds and subsequent instars feed on the leaves. Larvae complete five instars and pupation occurs in a folded leaf.
Host plants
Oak (Quercus sp.) is the primary host and in outbreak conditions T. viridana can cause extensive defoliation of oak trees. Defoliation affects tree growth, reproduction, and increases the chances of damage by other insects and frost. This species is regarded as one of the most important tortricid forest pests in southern Europe.
Secondary hosts include blueberry (Vaccinium sp.), nettle (Urtica sp.), and possibly other species not listed here - records on Norway spruce (Picea abies), poplar (Populus sp.), and raspberry (Rubus sp.) could not be verified.
| Family | Genus/species | Common name |
| Aceraceae | Acer L. | maple |
| Betulaceae | Carpinus betulus L. | European hornbeam |
| Ericaceae | Vaccinium L. | blueberry |
| Fagaceae | Fagus sylvatica L. | European beech |
| Fagaceae | Quercus ilex L. | holly oak |
| Fagaceae | Quercus L. | oak |
| Fagaceae | Quercus pubescens Willd. | downy oak |
| Fagaceae | Quercus robur L. | English oak |
| Fagaceae | Quercus suber L. | cork oak |
| Rosaceae | Prunus armeniaca L. | apricot |
| Salicaceae | Populus L. | cottonwood |
| Salicaceae | Salix L. | willow |
| Urticaceae | Urtica L. | nettle |
Distribution
Tortrix viridana is found in Europe and northern Africa.
References
Bradley, J. D., W. G. Tremewan and A. Smith. 1973. British Tortricoid Moths - Cochylidae and Tortricidae: Tortricinae. The Ray Society, London, England.
Crop Protection Compendium. 2007 Edition. CAB International, Wallingford, UK, 2007.
Razowski, J. 2002. Tortricidae of Europe, Vol. 1, Tortricinae and Chlidanotinae. Frantisek Slamka, Slovakia. 247 pp.
Photo Credits
Fig. 5: Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org
Figs 6-9: Milan Zubrik, Forest Research Institute - Slovakia, Bugwood.org
Fig. 10: Petr Kapitola, State Phytosanitary Administration, Czechia, Bugwood.org
