The Colorado potato beetle (Leptinotarsa decemlineata Say.) (CPB) is the main potato pest in Croatia. The main problems in CPB control are related to a number of treatments and resistance development. In order to investigate the efficacy of combinations a reduced dose of spinosad (33% of the full doses) with the reduced doses (33% of full doses) of B.t.t., neem and pyrethrin against CPB larvae, 3-year field trials and one laboratory trial were conducted. Joint actions of the insecticides in combinations were analyzed. The CPB attack on experimental fields in all 3 years of investigation was high to moderate. In 2001 the maximum number of larvae on untreated plots was 11.7 larvae per plant, while in 2002 and 2003 it was lower, 5.5 and 6.1 larvae/ plant, respectively. The efficacy obtained with a full dose of B.t.t. reached 75% in the field, and 78% in the laboratory trial. The residual efficacy of a full dose of B.t.t. lasted 7-10 days. The application of both, full and reduced doses of B.t.t., did not result in a significant yield increase. The results indicate that only one treatment with B.t.t. insecticide alone is not enough for efficient protection of potato against the attack of CPB larvae. The application of neem resulted in an efficacy of between 54 and 87.9%. The residual activity of neem was too short to ensure significant yield increase in 2 out of 3 years of the investigation. The application of a full dose of pyrethrin ensured an efficacy of between 86 and 89% with residual activity of 7-10 days. Only in the trial in 2003 significant yield increase (40% higher than untreated control) after the application of a full dose of pyrethin was recorded. The application of both, full and reduced doses of spinosad resulted in very high efficacy (over 90%), with residual activity between 10 and 20 days. The application of spinosad resulted in a significant yield increase in 2003, both in full and reduced doses, and in 2001 in the full dose (the reduced dose was not tested alone in 2001). High efficacy of the reduced dose of spinosad indicated its high biological activity and possibility for the reduction of the recommended dose. However, applications of combinations of insecticides in reduced doses (spinosad with B.t.t., neem and pyrethrin) resulted in efficacies of over 97% with residual activity of up to 21 days. Significant yield increase was noted after the application of the combinations of spinosad with B.t.t. and pyrethrin. The results of the laboratory trial confirmed the results of field trials. The joint action of insecticides was mainly described as independent synergism. It can be concluded that applied combinations are suitable in IPM in potato.

Potato cyst nematodes (PCN) Globodera rostochiensis (Wollenweber, 1923) Behrens, 1975 and Globodera pallida (Stone, 1973) Behrens, 1975 are the most troublesome pests of potatoes worldwide. Since 1968 there have been no investigations of the presence of PCN in ware potato lands in Croatia although these pests were recognised as an A1 plant-health quarantine species. After the Wrst discovery of G. rostochiensis in the locality of Belica (Medjimurska County) in 2001, intensive monitoring of the distribution of PCN in Croatia started. In 2001 G. rostochiensis was detected in 55% of soil samples taken in ware potato lands. In 2002 G. rostochiensis was detected in 4.1% of soil samples and in 0.08% of soil samples in mixed populations with G. pallida. The pathotype Ro1 was found in all tested populations and Ro1 and Pa 2/3 were detected in populations from localities Vidovec, Ivanovec and Sivice. In 2003 G. rostochiensis was detected in 1.03% of soil samples, and also in 12.8% of soil samples collected in 2004. In 2003 cysts of G. rostochiensis were detected in several seed potato Welds. These results indicate the urgent need for the application of further control measures to determine the presence and distribution of PCN in ware and seed potato lands in Croatia, in order to prevent the spread of PCN to noninfested areas. Integrated management strategies, neglected until 2001, have now been implemented and will prevent the build-up of infestation and replace the previous practices of monoculture, the use of short rotations and growing susceptible cultivars.

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The golden potato cyst nematode, Globodera rostochiensis (Wollenweber, 1923) Behrens, 1975, is the most problematic pest of potato (Solanum tuberosum L. subsp. tuberosum) worldwide and it is recognized as an A1 plant health quarantine species. In Bosnia and Herzegovina, there have been no surveys for the presence of potato cyst nematodes (PCN) in ware potato lands, although they have been documented in the nearby countries of Serbia and Croatia (3). To determine the presence and distribution of PCN and to prevent further spread or increase of PCN populations, a survey in ware potato land was undertaken in 2008, 2009, and 2010. Soil samples consisting of 100 cores of 4 to 5 ml of soil were taken in a grid pattern throughout the plots. Samples of approximately 500 g were processed in the laboratory. The samples were air dried and cysts were extracted using a Spears's flotation method (4) from a 100-ml subsample. Species identification was based on morphometrical characters (2) and real-time PCR where the ribosomal internal transcribed spacer (ITS5, PITSr3) region was amplified and detected by the Sequence Dection Software v1.3 (Applied Biosystems, Carlsbad, CA) (1). In 2008, soil sampling was conducted in five locations and PCN were not detected in any of 10 soil samples taken. In June 2009, 17 soil samples were collected from seven locations. Two viable cysts of G. rostochiensis were detected in one soil sample from Tihaljina (Zaside; E 6447659.560, N 4797392.101, altitude 130 m). A total of 110 soil samples were collected from 90 locations in May and June 2010. Five viable cysts of G. rostochiensis were detected in one soil sample taken from Čapljina (Opličići – Turajlovina; E 6485169, N 4775964, altitude 222 m). On the basis of the survey results, G. rostochiensis is not widely spread but the cysts are detectable, indicating that the infestation is relatively recent and that there is a threat of further spread of this quarantine species. Consequently, producers need to grow resistant potato cultivars and implement additional control measures to keep the nematode populations below damaging levels. References: (1) J. Bacic et al. Russ. J. Nematol. 16:1, 61, 2008. (2) C. C. Fleming and T. O. Powers. Potato Cyst Nematodes: Biology, Distribution and Control. R. J. Marks and B. B. Brodie, eds.CAB International, Wallingford, 1998. (3) D. Grubišic et al. J. Pest Sci. 80:21, 2007. (4) J. F. Spears. Agr. Handb. No. 353. U.S. Dep. Agric., 1968.

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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.