Testing of Theysohn traps efficacy, modified with the aim of reduction of collateral catches of checkered beetle (Thanasimus spp.), in the pheromone catches of spruce bark beetles in Gorski kotar

Klopkama, uz ciljanu vrstu organizma, uhvate se i neciljane, pa i parazitske, čija zastupljenost u ekosustavu utječe na smanjenje broja štetnika. Povećani broj klopki na određenom lokalitetu utječe na povećani broj korisne entomofaune u ulovima. Razvojem feromona za ciljane vrste, prilagođuju se i klopke s ciljem smanjenja kolateralnih ulova. Uprava šuma Delnice feromonski monitoring smrekovih potkornjaka provodi od 1995. g., a velike površine smrekovih šuma nakon niza ekscesnih pojava u posljednjih 10 godina stradale su nakon gradacije Ips typographus. Na području UŠP Delnice na dvije lokacije postavljeno je pet parova standardnih i modificiranih Theysohn® klopki suhog tipa. Modifikacija u obliku mreže 6x6 mm postavljena je s pretpostavkom zaustavljanja krupnijih vrsta, pa i Thanasimus spp. Dvomjesečno sakupljanje ulova u razdoblju proljetnog rojenja, laboratorijska obrada i statistička interpretacija podataka korištena je za donošenje zaključaka prema postavljenim ciljevima. Modificirana klopka ukazala je na značajno smanjenje kolateralnih ulova, ali i manji broj potkornjaka u 4 od 5 lovnih posuda. Thanasimus spp. u ovom bioklimatskom području aktivniji je u kasnijem ljetnom periodu, stoga tijekom provođenja istraživanja nije uhvaćena niti jedna jedinka. Podaci su uspoređeni sa sličnim istraživanjima drugih autora. Zbog različitosti u dobivenim podacima, ovo testiranje ima prostora u proširenju istraživanja na cijeli period potkornjačke aktivnosti, povećanju broja parova te dodatne modifikacije.Traps, in addition to the targeted type of organism, also catch non-targeted ones, including parasitoids, whose presence in the ecosystem affects the reduction of the pest’s number. The increased number of traps at a certain locality, affects the increased number of beneficial entomofauna in catches. By developing pheromones for target species, traps are also adapted with the aim of reducing collateral catches. Forest office Delnice has been conducting pheromone monitoring of spruce bark beetles since 1995. After a series of excesses in the last 10 years large areas of spruce forests have died due to an outbreak of Ips typographus. Five pairs of commercially available non modified and specifically modified dry type Theysohn® traps were placed at two locations in the area of forest office Delnice. The modification in the form of adition of a 6x6 mm sieve was set with the assumption of stopping larger, non-target species, including Thanasimus spp. Two-month catch collection during the spring flight of I. typographus, laboratory processing and statistical interpretation of the data was used to bring conclusions according to the set goals. The modified trap indicated a significant reduction in collateral catches, but also a smaller number of bark beetles in 4 out of 5 traps. Thanasimus spp. in this bioclimatic area is more active during summer period, therefore not a single individual was caught during the research. The data was compared with similar research by other authors. Due to the differences in the obtained data, this research might be extended to the entire period of bark beetle/Thanasimus activity, by increasing the number of pairs and making additional modification changes