Recognition of adults
FWL for adults: 6.0-7.5 mm
The anterior tip is yellow or yellowish orange with a well-defined median fascia of dark brown to black. Males and females do not show sexual dimorphism in the wing pattern, although females may be a bit larger than males. The males lack a front costal fold. The male genitalia are distinguished by a reduced uncus, short socii, prominent transtila, distal triangular valve, and large aedeagus. The female genitalia are distinguished by a broad, short ductus burasa and a corpus bursae with numerous sclerotizations and spines.
Adults can be confused with other species of Eupoecilia or European cochylini, although E. ambiguella is the only cochylid commonly associated with the grape. A genital dissection can be used to confirm the identity of E. ambiguella.
Late instar larvae are approximately 10-12 mm in length. The head, the prothoracic shield and the legs are dark brown to black. The color of the body varies from brown to yellow and green. The pinacula is large, striking and brown. The anal shield is light brown.
The larvae cause similar damage to Lobesia botrana and the two species can be found sympatrically. Other tortured grape pests include: Argyrotaenia franciscana, Argyrotaenia ljungiana, Postvittana Epiphyas, Viteana Paralobesia, Stultana Platynota, and Proeulia spp. The larvae of E. ambiguella can be separated from the larvae of other tortric-feeding grape pests by the L-group (or prespiracular) pinaculum in T1, which extends horizonally under the blowhole in E. ambiguella.
The life cycle of E. ambiguella is similar to that of Lobesia botrana, with the exception of two generations for E. ambiguella versus three or more generations for L. botrana. In most of their range, the dults are present in May and June for the first generation and again in August and September for the second generation.
The females deposit eggs alone in buds, pedicels and flowers during the first generation, and in grape berries during the second generation. Larvae of early instar burrows in buds or berries and are internally fed; the last instars form buds or berries, and a single larva can feed on up to a dozen berries. Pupation occurs on the leaves for the first generation and under the bark for the second generation. Hibernation occurs as a second generation pupa. Development time depends largely on temperature and humidity. The optimum level of relative humidity for development is 70% or higher; the eggs will not hatch at low levels of relative humidity.
The economic losses in the grape are caused by direct damage to food and secondary infections. The damage in feeding is similar to that of Lobesia botrana. Larvae of the first generation cause minor damage by feeding on flower buds, while those of the second generation cause the greatest damage by feeding on grape berries. The most important losses are due to the secondary infection of Botrytis cinerea in feeding sites of berries and bunches. The economic thresholds vary according to the type of grape and cultivate.
It is present in most of Europe and in different regions of Russia. The area extends from Asia Minor to the Caucasus, Siberia to Iran, to reach India, China (Anhui, Fujian, Gansu, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangxi, Shaanxi, Shanxi, Sichuan, Tianjin , Xinjiang, Yunnan, Zhejiang) and Japan. It is absent in North Africa and there is not enough information about its presence in many Mediterranean islands. Outside Eurasia, the species is found in Brazil, after an accidental introduction.2
Although it is usually associated with the vine, which is considered a plague, the moth is characterized by a marked polyphagy feeding on both herbaceous and woody species, usually with fruits, berries or similar, belonging to genera such as Ribes. , Rhamnus frangula, Hedera helix, Rhamnus cathartica, Lonicera, Viburnum, Ligustrum, Juniperus and Hedera. This polyphagy is manifested, in particular, in the regions located beyond the vine-growing zone.