Genetic identification of new alien pest species Illinoia liriodendri and its parasitoid Areopraon silvestre in Croatia.
Background and Purpose: During June 2015 in Zagreb city area (Croatia) samples of tulip tree (Liriodendron tulipifera) leaves were collected with symptoms of attack by some unknown aphid. Material and methods: Aphids were collected form leaves of tulip trees on different locations in Zagreb during July 2015. Total genomic DNA was extracted from ethanol-preserved specimens. PCR analysis was carried out and PCR products were purified from 1% agarose gel for sequencing purposes. The obtained sequences were deposited in GenBank. Results: The collected aphids were genetically determined as Illinoia liriodendri (Hemiptera, Aphididae), the North American invasive pest species. Although present in several neighboring countries on tulip trees in urban environment, this research presents the first record of Illinoia liriodendri for Croatia, confirmed on the genetic level. Interestingly enough, during genetic determination of tulip tree aphid pest, another DNA, one of parasitoid Areopraon silvestre (Hymenoptera, Braconidae) was also found in the collected samples. A. silvestere is a native European specialized solitary endoparasitoid of aphids. Conclusions: The presence of alien pest species Illinoia liriodendri was successfully determined via genetic identification. Also, genetic identification of parasitoid species on Illinoia liriodendri, Areopraon silvestre, shows the quick establishment of natural regulation of new pest species in Croatia.