A new pest of horse chestnut: Cameraria ohridella
In several countries of Central Europe, a new pest of horse chestnut (Aesculus hippocastanum) has been reported. Cameraria ohridella is a new species of lepidopteran leaf miner which was described in the Republic of Macedonia in 1985 (Deschka ; Dimic, 1986). Attacked leaves show transparent leaf mines of approximately 4 cm long with a brown centre. Heavy infestations lead to brown discoloration and death of the leaves, and finally defoliation of the tree. Inside the mines, small larvae of 1-4 mm long (according to development stage from L1 to L5) can be found. Their yellowish body is strikingly flat with bulbous segments. Brown pupae of 3.5-4 mm long can be found in autumn in pupal chambers inside the leaves. Adults are small moths with reddish gold forewings of 2.8 to 3.8 mm long, with white transverse bands underlined with a narrow black line. Hindwings are feathery. Antennae are almost as long as the forewings. Cameraria ohridella was then reported in 1989 in Austria where it spread to the whole country by 1994 (Krehan, 1995). In 1992, it was found in Upper Italy in Toblach (Trentino-Alto Adige) and, in 1993, in south Germany (Butin ; Führer, 1994). In Hungary, an outbreak was found in 1994 (Szaboky, 1994) and continued in 1995 (Czencz ; Bürgés, 1996). It appeared that the pest could overwinter in Hungary as pupae in fallen leaves. In 1995, 3 generations were observed. Each generation took about 35-50 days. In heavily, infested trees, damage could reach 30-40 % in June and increased to 80-90 % in August. Finally, during the EPPO Workshop for Phytosanitary Inspectors (Nitra, SK, 1996-10-15/18), its presence in Slovakia was also reported.
Sources
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Nachrichtenblatt des Deutschen Pflanzenschutzdienstes, 46(5), 89-91.
Czencz, C.; Bürgés, G. (1996) [The horse-chestnut leaf miner (Cameraria ohridella Deschka et Dimic, 1986, Lep.; Lithocolletidae)]
Növényvédelem, 32(9), 437-444.
Deschka, G.; Dimic, N. (1986) [Cameraria ohridella sp. n. (Lep., Lithocolletidae) from Macedonia, Yugoslavia.]
Acta Entomologica Jugoslavica, 22(1-2), 11-23.
Krehan, H. (1995) [Horse chesnut leafmining moth Cameraria ohridella, incidence of attack in Austria.]
Forstschutz-Aktuell, 16, 8-11.
Szaboky, C. (1994) [The occurrence of Cameraria ohridella in Hungary.]
Növényvédelem, 30(11), 529-530.