Die Kastanienminiermotte Cameraria ohridella Deschka & Dimic, 1986, als Neozoon in Bayern und die Auswirkungen ihres Massenvorkommens

摘要

As early as 1991 the Horse Chestnut Leaf Miner Cameraria ohridella reached the Lower Bavarian valley of the river Inn and late in the summer of 1992 a mass development occurred which caused an early leaf fall in August in a Chestnut alley of one of the villages (Ering) there. The chestnuts which fell from highly infested trees showed reduced weight of about 40 per cent compared with those from a weakly infested one nearby. Fig. 1 gives the change in abundance of chestnuts across the weight classes. But a recent study in the western part of the city of Munich revealed a much lower degree of weight reduction by only half of the amount a decade earlier (22 per cent) which looks like a compensation achieved by the trees after a prolonged exposure to these invasive leaf mining microlepidoptera. No substantial damages can be stated for the trees now after 12 years of mass occurrence of this pest species which probably came from the same refugial area of the Southeastern Balcans like the Horse Chestnut, which had been brought to Central Europe half a millenium ago.