Abstract: The yellow-legged clearwing moth, Synanthedon vespiformis L. (Lepidoptera,Sesiidae), a native species to central and South Europe, had been reported to occur on maron(Castanea sativa), as well as rarely on almond (Amygdalus communis) and peach (Prunuspersica), while in silviculture on beech (Fagus silvatica), oak (Quercus spp.) and occasionallyalso on poplar (Populus spp.), willow (Salix spp.) and on some other woody species. Strikinglyand unexpectedly, it heavily attacked thornless blackberry (Rubus fruticosus) in 2006 at Nógrádcounty, Hungary, and since that time it may cause up to 30% death of bushes of some plantations.It was detected en mass also on raspberry (Rubus idaeus) plantations in 2009 in that region, bymeans of the newly developed sex attractant traps.The objectives of this study were (1) to check whether the same sex attractant is a usefultool for monitoring the flight of various populations of this pest, living on different host plants /habitats (oak, and blackberry), (2) to follow seasonal flight pattern of the pest in various cultivarsof blackberry, (3) to determine the circadian rhythm of trap captures and (4) to map thedistribution of the pest in Nógrád county.Sticky (RAG) as well as of large capacity, funnel type of pheromone traps (VARL+)(CsalomonÒ, produced by the Plant Protection Institute, Hungarian Academy of Sciences,Budapest, Hungary) were used in course of the season of 2009 (objectives 1 and 4), and furthertrials have been running in 2010 (objectives 2 and 3). Trapping sites were chosen so that anisolation distance of at least 500m was kept between various hosts.Results show that the same sex attractant is a useful bait for monitoring for all populationsof S. vespiformis, living either in oak forest, or in blackberry plantation, or in raspberryplantation. Significant captures were recorded in plantations of both the „Loch Ness“ and„Thornfree“ cultivars of blackberry, showing a more-or-less similarly continuous flight in courseof the season. Male moth entered the traps predominantly in the afternoon (15:00-19:00). Thepest was abundant in all of the checked black- and raspberry plantations in Nógrád county(Hungary).Effective control measures are needed not just for achieving good yield of berries at harvest,but in blackberries also for preventing die out of bushes. Recently used methods are costy forfarmers and require heavy application of pesticides, therefore new, environmentally-soundmethods would be needed.