Cameraria ohridella Deschka & Dimic
Lepidoptera: Gracillariidae
Multivoltine species, up to 3 generations per year (V-X.) the last generation sometimes only partly complete its development. The larvae make irregular blotch mines on the upper surface of the leaves of Aesculus species, (mainly A. hippocastaneum in Europe). Once it was also reported from sycamore, Acer pseudoplatanus. The species was first found in Macedonia at Lake Ohrid, very close to the Albanian border, in 1985, and was described as a species new for science one year later. The real origin of the species is not yet known. The genus Cameraria is not represented by any other species in Europe, but quite a few species belonging to the genus can be found both in Asia and North America. This fact supports the hypothesis that the species was accidentally introduced to Europe. The most likely explanation is that it was introduced to Albania by Chinese settlers, and after its establishment it started to spread on its own way, expanding its area into the states of the former Yugoslavia by the late 80s. In 1989 it was already found in Zagreb, capitol of Croatia. In the same year it was introduced on purpose to Linz, Austria by an entomologist in order to study it - without considering the potential consequences of its escape. After its escape this Austrian location served as starting point to many European countries. Its spread was probably helped by the road traffic. It reached Germany and France in 1992, Czech Republic in 1993, Slovak Republic in 1994, Switzerland and Poland in 1998. It was first recorded from SW Hungary in 1993. In the same time it was probably already also present in the NW part of the country. It means that the invasion reached Hungary from two different directions in the same time (from Croatia and Austria). By 1997 the species had shown an explosion like expansion and was distributed throughout the whole country, intruding into Western parts of Ukraine and Romania. At present the insect can be found everywhere in Hungary where its host is present, and has become extremely abundant at many places. The first generation usually attacks the lower part of the crown, but the 2nd and 3rd generation already attack the higher parts too. Heavy infestations cause browning and early fall of the leaves as early as July, and the long term impact of the chronic defoliation is not yet known. The main host, A. hippocastaneum is one of the most common and popular ornamental trees, both in Hungary and in Central Europe and can be found in nearly every town and village. It is also one of the preferred shade trees along the roads between towns and villages. These lines of roadside trees probably accelerated the expansion of its range significantly. There are several control methods are recommended against the damage of this species, as spraying with special technologies and injecting the stem with insecticides.
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