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The aim of this study is to identify plant lice Cacopsylla pulchella a new alien insect in the fauna of Croatia. We propose a new method of infestation level assessment in order to assess the potential of this insect as a pest. In May 2020 samples were collected from eleven locations in Croatia, where Cercis siliquastrum is grown in parks. Adults and nymphs of C. pulchella were collected together with a plant material and brought to entomological laboratory for further analysis. Field research was performed in order to assess the distribution and infestation intensity across various localities in Croatia. The intensity of infestation was assessed heuristically by visual examination and was categorized in four categories: 0) no infestation, 1) low, 2) moderate and 3) high infestation. C. pulchella was confirmed on C. siliquastrum in eleven localities in Croatia. Most of the infested trees had a low or moderate intensity of infestation. Damages caused by this insect are due to the emission of honey dew, a small spherical drop covered with waxy secretion causing necrotic areas which could lead to the premature fall of the leaves. It is not known what kind of progress in infestation intensity could be expected so infested trees found in this study should be checked closely in the coming years. It is strongly suggested to continue the monitoring of this alien insect on C. siliquastrum in Croatia and to estimate its potential of become an invasive pest which could endanger ornamental and other values of its hosts.

Previous study of Black cherry (Prunus serotina Ehrh.) species in Pedunculate oak (Quercus robur L.) forest regeneration area of Jastrebarsko forest management unit have shown a considerable spread, indicating its invasive character and alteration in current vegetation. In this respect, the continuation of this research is focused on monitoring of spreading area and its impact on the native plant species. Also, as a part of the detection programme of Rhagoletis species in Croatia, this research includes defining potential occurrence of Cherry fruit fly (Rhagoletis cingulata) species, naturally associated with the P. serotinas’ presence. With the aim of sampling both infected and uninfected parts of the monitored area, our survey consists of 20 polygon network plots created in QGis programme and equally distributed into polygon of the regeneration area (15 plots), as well as the surrounding forest area (5 plots). In order to investigate current habitat characteristics, phytosociological approach is applied. Furthermore, the area is surveyed by the use of the unmanned aerial vehicles (UAV) DJI Mavic 2 Pro and DJI Matrice 600, both equipped with multispectral cameras and DJI Ground Station Pro for comparing results. Data analysis is performed by the use of Agisoft Metashape Professional (ver.1.5.5) programme. In addition, monitoring of Rh. cingulata species includes yellow sticky board traps located on the edges of the regeneration area. This research reveals spreading capacity and the expansion rate of P. serotina as well as Rh. cingulatas’ presence in the monitored area. With better understanding of ecology changes over a certain period of time, this also contributes to drawing conclusions about the effectivness of the control measures being implemented.

Previous findings of Black cherry (Prunus serotina Ehrh.) species affected during its growing season (2018-2021) in Pedunculate oak (Quercus robur L.) forest regeneration area of Jastrebarsko forest management unit have shown a considerable spread and alteration in current vegetation. The continuation of research is focused on monitoring its spreading area as well as its impact on the current habitat characteristics. In addition, this research includes defining potential occurrence of Cherry fruit fly (Rhagoletis cingulata) species, naturally associated with the P. serotinas’ presence. With the aim of sampling both infected and uninfected parts of the monitored area, our survey consists of 20 polygon network plots equally distributed into polygon of the regeneration area (15 plots), as well as the surrounding forest area (5 plots). In order to investigate current habitat characteristics, phytosociological approach is applied. The area is surveyed by the use of the unmanned aerial vehicles (UAV) DJI Mavic 2 Pro and DJI Matrice 600, both equipped with multispectral cameras and DJI Ground Station Pro. Monitoring of Rh. cingulata includes 20 yellow Chromotraps and 8 Tephri-Traps located on the edges of the regeneration area. The results confirm invasive capacity of P. serotina indicating a concerning potential of its subsequent expansion in the near future. In this regard, P. serotinas' progression monitoring is highly recommended as one of the control measures of its development.

Monitoring of pests, native or alien invasive is a key activity in prevention of damages in forests. Conventional monitoring methods (pheromone traps, visual transects, glue rings etc) are time consuming and require significant financial inputs. Development of remote sensing sensors, GPS technology and geographic information systems (GIS) support novel approach towards detecting pests, which has the potential of accurately measuring pest damage and populations on a whole area basis. Accurate and efficient monitoring of insect populations is a key point to improve pest control and mitigate damages. Technical limitations of remote scouting, especially resolution of satellite and aerial images, have until recently precluded wide scale adoption. Recent technological advancements have increased resolution of visible and NIR sensors while also decreasing size and cost providing more affordable ways to assess forest health. Therefore, usage of small aerial vehicles or drones equipped with multispectral sensors could provide a better insight into forest stand health and damages caused by pests. With relatively low-cost platform, we have insight on the area with better resolution than with those from satellite. Surveys of quarantine pests in forests are being conducted in Croatia, and those are co-financed by European commission. European food safety authority (EFSA) is recommending usage of unmanned aerial vehicles (UAVs) as a versatile remote sensing-based toolkit for monitoring forest health and occurrence of forest pests. Use of UAVs for monitoring of Bursaphelenchus xylophilus and Polygraphus proximus has been applied in Croatia.

Monitoring of small rodents (Murinae:mice ; Arvicolinae:voles) in the state forests of Croatia has been carried out systematically for over 40 years by Croatian Forest Research Institute (CFRI) and Croatian forests, limited liability company, that is a public enterprise for forest and woodland management in the Republic of Croatia. From the beginning of the 1980s to 2016, monitoring included estimating the intensity of damage caused by rodents (%) and recording the size of forest areas (ha) with noticeable damage to seeds and saplings of economically important tree species. Since 2017, the rodent monitoring has been extended to determine the relative abundance (RA ; %) by trapping rodents, as well as to determine the share of damaged seeds and tree saplings (%). The aim of this work was to analyze the trends and results of rodent monitoring carried out from 2017 to 2020. Data was provided by CRFI (stetnici.sumins.hr) and analysed using Microsoft Excel 365. In that four year period overall damage caused by rodents in Croatian state forests were recorded on 16.506, 2 ha (avr. 4.1236, 55 ha) and rodents were treated using rodenticides (API Zinc phosphide) on 13.343, 41 ha (avr. 3.335, 85 ha). Monitoring included 11 (out of 17) (avr. 8) Forest Administrations – Subsidiaries (FAS) (Vinkovci, Zagreb, Sisak, Našice, Nova Gradiška, Osijek, Bjelovar, Požega, Koprivnica, Slatina, Karlovac), 40 (out of 169) regional forest offices (RFO) and 214 trapping locations average per year. Overall 14.263 (avr. 3.566) small rodents (mice: 11.976 ; avr. 2.994 ; voles: 2.020 ; avr. 505 ; not deremined: 267, avr. 67 ) were trapped. Average relative abundance (RA) in all FAS varied from 7, 4 % to 23% per year with maximum RA 92% that was recorded in FAS Osijek in year 2017. Average share of sedlings with damaged bark varied annualy from 0, 2 % to 9, 5 % (avr. 5, 0 % ; max. 66, 7 %) and of those with domaged root from 0, 2 % to 3, 1 % (avr. 0, 9% ; max. 23, 3 %). Damage on forest seeds varied overall from 0, 3 % to 4, 8 % (avr. 2, 6 % ; max. 36, 6 %). Eventhaugh the average annual relative abundances, nor the damage on seedlings or seeds don’t indicate rodent mass occurence at FAS level, it is important to approach and interpret rodent monitoring and provide protection measures for every regional forest office, and further more for every specific microlocation on which monitoring takes place. Can this relatively low damage on samplings be exlained by the high share of mice (> 80 %) recorded continuously during all four years? Shouldn’t we expect more severe damaged on the seeds if the species from Murinae subfamilies are so dominant over Arvicolinae? Do we need to reconsider the monitoring methodology in years to come? Continuous monitoring should provide further answers.

U Hrvatskoj su mjere zaštite šuma obveza šumovlasnika koje su propisane Zakonom o šumama, Zakonom o zaštiti bilja, Zakonom o zaštiti od požara te nizom drugih zakona i podzakonskih akata. Podaci koji su prikazani u radu dobiveni su obradom službenih podataka Izvještajno prognoznih poslova u šumarstvu Hrvatskog šumarskog instituta u 2018. godini. Poznavanje dinamike populacija štetnih abiotičkih i biotičkih čimbenika preduvjet su pravovremene i kvalitetne zaštite u svrhu smanjenja njihovog negativnog utjecaja u šumama Hrvatske. U 2018. godini zabilježena je zaraza hrastovom pepelnicom (Microsphaera alphitoides) na površini od 8 766 ha. U tretiranju ove bolesti utrošeno je preko 5 200 litara zaštitnih sredstava. Najintenzivniji napad hrastove pepelnice zabilježen je u šumama kojima gospodari poduzeće Hrvatske šume d.o.o., Uprave šuma Podružnice (UŠP) Bjelovar i Vinkovci. Sušenje poljskog jasena zabilježeno je na 35 770 m3 kao posljedica višegodišnjeg djelovanja više biotičkih i abiotičkih faktora (nepovoljni utjecaj klimatskih promjena, povećana brojnost jasenove pipe (Stereonychus fraxini), promjena režima podzemnih voda, povećan broj i intenzitet poplava, masovna pojava jasenovih potkornjaka (Hylesinus crenatus i H. fraxini), pojava gljive Chalara fraxinea). Gradacija gubara (Lymantria dispar) je zabilježen na površini 1 035 ha, a najveći intenzitet napada je bio na području šumarije Koška (UŠP Našice). Veliki (Erannis defoliaria) i mali mrazovac (Operophtera brumata) su utvrđeni na površini od 10 359 ha, dok je hrastov četnjak (Thaumetopoea procesionea) evidentiran na ukupnoj površini od 10 142 ha. Hrastov četnjak je suzbijan na 7 470 ha primjenom 22 096 l preparata Forey 48B. Gradacija borovog četnjaka (Thaumetopoea pityocampa) je bila na 701 ha, dok je napad hrastove mrežaste stjenice (Corythucha arcuata) zabilježen na površini od 140 486 ha. Mjere zaštite protiv sitnih glodavaca su zabilježene na 3 478 ha. Oštećenja od ledoloma, snjegoloma i vjetroloma sa intenzitetom od 21% do 40% zabilježena su na površini od 42 937 ha.

U radu je prikazana dinamika populacija gubara (Lymantria dispar L.), velikog mrazovca (Erannis defoliraia Cl.), malog mrazovca (Operophtera brumata L.), jasenove pipe (Stereonychus fraxini De Geer), borovog četnjaka gnjezdara (Thaumatopoea pityocampa Seiff.), jelovog krivozubog potkornjaka (Pityokteines curvidens L.), smrekovih potkornjaka (Ips typographus L., Pityogenes chalcographus L.) i sitnih glodavaca u razdoblju od 2008. do 2017. godine. Podaci su dobiveni obradom službenih podataka Izvještajno prognoznih poslova u šumarstvu Hrvatskog šumarskog instituta za razdoblje od 2008. do 2017. godine u svrhu boljega razumijevanja vremensko-prostornih fluktuacija brojnosti najznačajnijih šumskih štetnika. Poznavanje njihove dinamike populacija preduvjet su pravovremenom i učinkovitom poduzimanju mjera zaštite u svrhu smanjenja negativnog utjecaja kojega mogu uzrokovati u šumskim ekosustavima Hrvatske. U promatranom razdoblju nalaz jasenove pipe je zabilježen na 155 416 ha. Najzastupljenija populacija ove vrste je bila 2009. i 2010. godine. Jelin krivozubi potkornjak je utvrđen na ukupnoj površini od 77 563 ha, dok je gubar zabilježen na 66 401 ha (najveća brojnost je bila 2013. i 2014. godine). Mali i veliki mrazovac su utvrđeni na površini od 55 086 ha, sitni glodavci na 45 184 ha, smrekovi potkornjaci na 35 955 ha, dok je borov četnjak gnjezdar evidentiran na ukupnoj površini od 20 183 ha. Uslijed napada jelovih potkornjaka (prvenstveno P. curvidens) ukupno je posječeno 492 969 m3 drvne mase (najviše 2008. godine u količini od 117 946 m3), dok je 454 437 m3 drvne mase posječeno nakon šteta koje su uzrokovali potkornjaci na običnoj smreci. Mjere zaštite protiv sitnih glodavaca su poduzete na površini od 33 538 ha, a najviše tijekom 2011. godine (4 910 ha) i 2014. godine (4 935 ha).

Torymus sinensis (Hymenoptera: Torymidae), a classical biocontrol agent of chestnut gall wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae), was released in Croatia, Slovenia and Hungary in 2015. Following the introduction, the research of parasitism rates and population genetic indices on 40 different sites was performed in order to monitor and evaluate the success of establishment. T. sinensis established viable and genetically diverse populations and successfully spread naturally from Italy across Slovenia to Croatia and Hungary. T. sinensis populations from release and non-release sites share common gene pool, adding to the hypothesis that the spread occurred naturally from Italy, even before official releases in Slovenia, Croatia and Hungary were done. Population genetic indices showed that populations of T. sinensis did not suffer from bottleneck-induced founder effect phenomenon. This rapid dispersal of T. sinensis was aided by high concentration of the host, as well as the lack of competition of native parasitoids

It has already been documented that climate change has negatively influenced forest health and enabled the establishment of non-native forest pests in Europe, especially wood-boring beetles coming from tropical and subtropical areas. But what if a native bark beetle species becomes invasive as a consequence of climate change? With the recent and ongoing outbreak of the bark beetle Orthotomicus erosus we would like to show a case of a native European forest pest that has strong potential to become invasive in Europe due to climate change. Several other native forest pests have already invaded large parts of Europe (e.g., Thaumetopoea processionea, Thaumetopoea pityocampa), while other native pests are waiting for the trigger (e.g., Abraxas pantharia, Lymantria dispar). It is predicted that Mediterranean forests will be more vulnerable to bark beetle attacks than temperate and boreal forests. Currently, Mediterranean forests are under severe threat from climate change and it is predicted by FAO that they will suffer from its impacts by 2050. Climate change could indirectly and negatively influence forest ecosystems through range expansion and changing of seasonal phenology of insect pests, and may result in faster development and higher feeding rates of phytophagous insects. Recent unusual heavy attacks by Orthotomicus erosus in Croatia seem to be associated with increased temperature and frequency and intensity of drought. Various early warning systems for invasive insect pests are continuously being developed and used, so an important question arises accordingly: should we also invest more into developing an early warning system for native pests that could behave like invasive?

Sweet chestnut (Castanea sativa) is a valuable forest species which is endangered by two highly invasive organisms: chestnut blight (Cryphonectria parasitica) and Asian chestnut gall wasp (Dryocosmus kuriphilus). These harmful organisms have significantly influenced health and function of European sweet chestnut forests. D. kuriphilus is the most recent introduction and in the last 10 years it has spread quickly in Europe making significant damages in sweet chestnut forestst. The only effective option was application of classical biological control and use of Torymus sinensis, a classical biocontrol agent of chestnut gall wasp Dryocosmus kuriphilus. The parasitoid was released in Croatia, Slovenia and Hungary in 2015 and 2016. Following the introduction, the research of parasitism rates and population genetic indices on 40 different sites was performed in order to monitor and evaluate the success of establishment. T. sinensis established viable and genetically diverse populations and also successfully spread naturally from Italy across Slovenia to Croatia and Hungary. Population genetic indices showed that populations of T. sinensis did not suffer from bottleneck-induced founder effect phenomenon. This rapid dispersal of T. sinensis was aided by high concentration of the host, as well as the lack of competition of native parasitoids. This successful application of classical biological control in forestry, first of its kind in Croatia, Slovenia and Hungary has enabled recovery and return of functions of sweet chestnut trees and lowering the population level and damages of D. kuriphilus.

Early warning against potentially harmful organisms of woody plant species is important for the prevention of pest introduction via the international trade in live plants. Recent studies of sentinel plants illustrate that this can be achieved by sampling woody plants in exporting countries. However, it is unclear where sentinel plants can best be located, and how many samples are required for the detection of pest risk or for an assessment of the diversity of organisms associated with the target plant species. It is also unclear when sampling should take place for the optimal detection of such organisms. The occurrence of organisms associated with a woody plant species is affected by global, regional and local factors, including climate or seasons, elevation, soil type, site management and plant genetic diversity. Therefore, such factors should be considered when deciding on the sampling design for early detection of harmful organisms. However, it is unknown which factors are most influential for the selection of locations and number of units for sampling for species diversity. We explored the importance of selected geographic and temporal factors, as well as costs for the design for sampling of organisms associated with any woody plant species using data from four case studies. Based on these case studies, we propose a generic scheme for the identification of optimal sampling locations and periods for potential harmful organisms. The scheme can be used irrespective of the targeted plant species or importing country.

Bark beetles have been documented as having relevant ecological and economic role in ecosystem functioning and their activity can indicate the health condition and vitality of forest. They are also very important forest pests that can cause serious dieback of forests on huge areas. With climate change there is a strong possibility that the frequency of their outbreaks will increase which makes Mediterranean forests more vulnerable to their attacks than temperate and boreal regions. Mediterranean forests have been strongly influenced by human activities over centuries but despite this, they have demonstrated strong resilience and possibilities of recovery from these influences. However, today they are under severe threat from climate change and it is predicted by FAO that the Mediterranean forest ecosystems will suffer from its impacts by 2050. Climate change could indirectly negatively influence forest ecosystems through range expansion and changing of seasonal phenology of insect pests, resulting in faster development and higher feeding rates of phytophagous insects. Recent heavy bark beetle’s attacks of the species Orthotomicus erosus in Croatia shows that the negative influence seems to be accelerated with increased temperatures and frequency and intensity of drought with extended growth period of vegetation. Other negative influences of climate change on forests could be shown in physiological changes in tree defences and indirect effects through changes in abundances of natural enemies and competitors. Large areas of pine forests in Dalmatia have been attacked resulting in death of up to 30 % of trees which makes this problem challenging for the forest sector in coming years

Live plants are often traded in winter or early spring when the number of pests is potentially low, in part because deciduous trees lack foliage. However, the pests that may be associated with traded dormant plant material are likely to be largely unknown. Pest risk assessments can only be performed for known pest species and it is therefore important to identify potential pests before they are moved to a new area. In addition, it is difficult to predict whether introduced pests, even if already well known, may shift host after their arrival. Several studies attempted to estimate the likelihood of host shifts using literature about known pest-host associations, but the number of pests in these studies was often limited and the data were unlikely collected in the same place and at the same time. To overcome these problems, we performed a global study which aimed at detecting potential insect pests and fungal pathogens on congeneric native and exotic woody plant species that belong to six studied tree genera. Sampling was done simultaneously in 33 countries around the world following a common sampling protocol. At each location, twenty 50 cm long, dormant twigs were collected from each tree species and kept in containers with water at room temperature. Emerged insects were collected and identified based on morphology and DNA barcoding of the mDNA COI region. Fungal DNA was extracted from pooled buds, twig parts and needles for species identification using a metabarcoding approach based on the rDNA ITS region. Here, we present preliminary results of this study and discuss them in the context of pest risk assessment.

Pests are distributed unevenly across a location, therefore choosing where to sample, and the number and frequency of samples, is key to increasing the chances of detection. Sentinel plantings are a promising tool for detecting potential pests prior to their introduction into a country. Identification of the majority of species associated with the plant is important in order to identify potential pests before they enter and establish in a country. Detection of a wide range of species, including rare species, requires intensive sampling which increases the costs of sampling. It is thus important to balance sampling effort and costs. Given that the sentinel planting concept is relatively new, there is a lack of information and guidance on sampling for sentinel studies. Here we explore statistical sampling designs for the assessment of species diversity associated with woody plants. We outline factors that may affect diversity on different spatial and temporal scales and illustrate their influence on the fraction of the expected diversity that may be captured using several different case studies. (i) Differences in fungal diversity among and within seed lots of woody plants from three continents were assessed to illustrate local and regional diversity. (ii) We illustrate how variation in biodiversity within and among years can be captured by looking at long-term data from 18 year- long sampling of early oak defoliators. (iii) We examine between year variations in the fungal diversity of herbaceous plants and (iv) within year diversity of insect in nurseries. We discuss, with reference to previous sentinel studies, how the factors that cause the spatial and temporal differences in the diversity may be included in the sampling design and suggest an optimal sampling design for sentinel plantings. We also assess the effect of increasing costs in order to increase species detection.

biološko suzbijanje u Sloveniji, Hrvatskoj i Mađarskoj unesenim parazitoidom Torymus sinensis

Kestenova osa šiškarica (Dryocosmus kuriphilus) se smatra jednim od najznačajnijih štetnika na pitomom kestenu (Castanea sativa). Jedini učinkoviti način kontrole ove invazivne vrste je biološko suzbijanje unesenom vrstom parazitoida Torymus sinensis. T. sinensis je monofagni parasitoid koji je fenološki i morfološki u potpunosti adaptiran na kestenovu osu šiškaricu, brzo se širi, brzo uspostavlja populaciju i vrlo je učinkovito sredstvo biološkog suzbijanja, T. sinensis je ispušten na više lokaliteta u Hrvatskoj od 2014., a u Sloveniji od 2015. godine nakon uzgoja u entomološkom laboratoriju iz suhih šiški kestenove ose šiškarice porijeklom iz Italije, Hrvatske i Slovenije. Genetičkim je analizama potvrđeno uspostavljanje populacije u šumama i nasadima pitomog kestena u Hrvatskoj i Sloveniji. Zajednički su razvijene laboratorijske metode uzgoja strane vrste parazitoida T. sinensis koje se koriste kao službeni protokol prilikom uzgoja i ispuštanja u Hrvatskoj i Sloveniji. Samo dvije godine nakon prvog ispuštanja na nekim lokalitetima u Hrvatskoj i Sloveniji parazitiranost je dostigla čak 90 %. To je rezultat ispuštanja hrvatskih i slovenskih znanstvenika i prirodnog širenja parazitoida iz Italije preko Slovenije do Hrvatske. Genetička istraživanja populacija T. sinensis iz Hrvatske i Slovenije pokazala su da se parasitoid brzo proširio u novim područjima bez postojanja genetičkog uskog grla.

Torymus sinensis (Hymenoptera: Torymidae), a classical biocontrol agent of chestnut gall wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae), was released in Croatia, Slovenia and Hungary in 2015. Following the introduction, the research of parasitism rates and population genetic indices on 40 different sites was performed in order to monitor and evaluate the success of establishment. T. sinensis established viable and genetically diverse populations and successfully spread naturally from Italy across Slovenia to Croatia and Hungary. T. sinensis populations from release and non-release sites share common gen pool, adding to the hypothesis that the spread occurred naturally from Italy, even before official releases in Slovenia, Croatia and Hungary were done. Population genetic indices showed that populations of T. sinensis did not suffer from bottleneck-induced founder effect phenomenon. This rapid dispersal of T. sinensis was aided by high concentration of the host, as well as the lack of competition of native parasitoids.

Dryocosmus kuriphilus is considered as one of the major pests of sweet chestnut (Castanea) and the effective method of controlling its populations and damage is classical biological control with its introduced parasitoid Torymus sinensis. T. sinensis is a univoltine, host specific parasitoid, phenologically synchronized and morphologically adapted to D. kuriphilus, it has good dispersal ability, builds up populations quickly and effectively controls the pest already few years after release. We describe the first results of introduction and release of T. sinensis for controlling the populations of invasive D. kuriphilus in sweet chestnut forests and orchards in Croatia, Hungary and Slovenia. Withered D. kuriphilus galls with T. sinensis larvae were collected in Torino vicinities, Italy in March 2014 and 2015. After emergence, males and females were put together, kept at 14°C and fed with liquid honey until release. To confirm the establishment of population of T. sinensis on release sites in Croatia, Slovenia and Hungary morphological and DNA identification were used.. In total 10, 590 females and 5, 295 males of T. sinensis were released in sweet chestnut forests across in Croatia, Hungary and Slovenia in 2014 and 2015. Minimum release number of T. sinensis was 100 females/50 males and maximum 1, 200 females per site. Subsequent releases with larger number of females (1, 200 and 800 in two years) resulted in rapid establishment of population of T. sinensis and parasitism rates of 76 % only one year after the first release was achieved. Establishment of population of T. sinensis was confirmed with molecular analyses and morphological identification High levels of genetic diversity indices showed that populations of T. sinensis did not suffer from bottleneck-induced founder effect phenomenon. Prior to release of T. sinensis all advantages and disadvantages of introduction of this alien biocontrol species into natural stands in Croatia, Hungary and Slovenia have been considered.

Box tree moth (Cydalima perspectalis) is an alien invasive species that has been recorded in Croatia for the first time in 2013 and since then it has rapidly spread across the whole country. Substantial damage to box tree plants have been recorded in many urban areas, especially in private gardens and other green areas located in the cities. Biology and influence of different food type on developmental characteristics will be presented here. Pheromone baited traps were used for the insight into the number of generations, while food choice experiment was conducted in the laboratory where we have compared three ornamental plant species (Euonymus japonicus, Ilex aquifolium and Ligustrum vulgare) with Buxus sempervirens. The food choice experiment showed that the box tree moth is able to complete its development only on B. sempervirens, while number of generations is still not confirmed since we had problems with pheromons that we have used in the experiment. Since outbreaks of this alien invasive species continue to appear in Croatia we have also made some preliminary insight into complex of parasitoids which revealed that native parasitoids have not yet switched to box tree moth. This research confirmed that the main pathway of alien invasive species introduction are live plants trade and that this commercial activity is a serious threath to indigenous plants and ecosystems.

Box tree moth (Cydalima perspectalis) is alien invasive species that has rapidly spread across Croatia making substantial damage to box tree plants. We are presenting results of biology and food choice tests of box tree moth in Croatia. Sex pheromones baited traps were used for detailed insight into number of generations and food choice tests were performed in laboratory comparing Buxus sempervirens, Euonymus japonica and Ilex aquifolium as host plants. Results showed that the moth is able to complete two generations per year, overwintering as young larva on plants. The food test showed that the moth is able to complete its development only on B. sempervirens. Severe outbreaks of box tree moth are continuing across Croatia and first insight into parasitoids complex has revealed that native parasitoids have not yet shifted to this novel invasive host. Our research has also confirmed that live plants trade is one of the main pathways of introduction of exotic plant pests which are becoming serious threath to indigenous plants and ecosystems.

The Asian sweet chestnut gallwasp, Dryocosmus kuriphilus (Hymenoptera, Cynipidae) is considered to be the most important pest of chestnut worldwide. Originating from China, this pest was accidentally introduced to Japan in 1941, colonized Korea in 1958 and the USA in 1974. In 2002 it was detected in Europe, Italy. Since then DK spread throughout Italy and has also been reported in all European countries where chestnut grows. Within the native range in China, 11 parasitoids species were found to associate with D. kuriphilus which kept the host populations at low densities ; in Japan, South Korea, the USA and European countries the attack rates of indigenous parasitoid species vary from 2% to 4.7%, We studied the native parasitoid assemblages of D. kuriphilus across it expanding range in Italy (since 2005), Slovenia (since 2010), Croatia (since 2011) and Hungary (since 2013). All parasitoid species are known to associate with oak cynipid galls. Most of them are generalists that can shift hosts more easily and are more successful in colonizing an invasive host and thus a large parasitoid diversity within the DK community can be expected. The aim was to study the source community of parasitoids available to attack the invasive host and the way in which they may associate with D. kuriphilus. Since 2005, 44 species shifted onto the new pest, D. kuriphilus. In Italy, 39 chalcidoid parasitoid species have so far recruited naturally to the new host, 28 in Slovenia, 20 in Croatia 20, and 17 in Hungary. The time lag between the introduction of the new host, D. kuriphilus, and the recruitment of native parasitoid community is short and depends on the longevity of pest’s presence on a particular site. Recruitment of parasitoids to D. kuriphilus depends on actual parasitoid species composition of oak gallwasps to be found in the same locality and varies from year to year.

Two invasive organism Dryocosmus kuriphilus and Cryphonectria parasitica are serios threat to chestnut stands, chestnut trees and the quality of the production of fruit. The interaction of the fungus C. parasitica and chestnut gall wasp D. kuriphilus and the role of other fungi on the necrotic gall wasp in chestnut stands were investigated during the 2012, 2013 and 2014 years. The study was conducted at 7 sites of Croatia: Medvednica, Ozalj, Samobor, Koprivnica, Lovran, Petrinja and Pokupsko where the 30 branches infected with wasp galls were colected randomly per site. On tree selected sites Samobor, Koprivnica and Pokupsko, three tres per site were felled to take the samples for additionall research in 2014 year. Branches were analysed for the presence of chestnut blight and necrotic gall wasp in the trees crown. From necrotic gall wasp the fungi were isolated and determinated using standard phytopathological and molecular methods. 10 gall wasp per site were randomly collected to investigated the presence of the fungi on D. kuriphilus larve. Chestnut fruit were collected on the localities: Medvednica, Samobor and Petrinja. Chestnut fruit were exemined for the presence of the fungi. From necrotic gall wasp the fungi C. parasitica, Gnomoniopsis sp., Colletotrichium acutata, Botryosphaera dothidea, Cytospora sp., Diaporthe eres, Botrytis cinerea, Trichothecium roseum, Trichoderma viride, Alternaria alternata, Penicillium sp. and Fusarium sp. were isolated. On chestnut fruit were determinated following fungi: Aspergillus niger, Aspergillus flavus, Gnomoniopsis sp., Colletotrichum acutata, Botryosphaeria dothidea, Ciboria batschiana, Alternaria alternata, Diaporte eres, Botrytis cinerea, Trichothecium roseum, Trichoderma viride, Penicillium sp., Fusarium sp. On the remains of dead larvae D. kuriphilus the fungi: Alternaria alternata, Botrytis cinerea, Fusarium sp, Penicillium spp were detected. The analysis of dry twigs above gall wasp show that thay were without symptoms of fungi infections and the reason of their drying were physiological conditions. On the chestnut tree crowns infected with D. kuriphilus the diversity of fungi and mutual presence of several types of fungi on gall wasp, larvae of wasp gall and chestnut fruit were observed.

IUFRO WP 7.03.07 "Population Dynamics of Forest Insects",IUFRO WP 7.03.06 "Integrated management of forest defoliating insects",IUFRO WP 7.03.13 "Biological control of forest insects and pathogens"&Forest Research Institute in Sękocin Stary, PolandRegional Directorate of State Forests in Gdańsk, PolandUnder the honory patronage of the Ministry of Environment; During the recent decades, ornamental plant trade has triggered the introduction of alien invasive insects in Europe. An ever increasing number of these alien species originates from Asia, such as the box tree moth Cydalima perspectalis, a species native of China, Korea and Japan, which has recently been introduced into Europe. Since its first observation in Germany in 2007, the box tree moth has spread rapidly all over Europe, causing important damage on commonly planted ornamental box trees. The ornamental trade between Europe and China is hypothesized as the pathway of its primary introduction while the trade within Europe could have favored its rapid spread. In order to disentangle invasion pathways, samples of C. perspectalis were collected in China, Korea and in 13 of the 25 invaded European countries. We analyzed 174 sequences of mitochondrial markers COI and COII from the native and invaded areas in order to check the genetic variability, and to develop a preliminary phylogeographical approach. In the Asian populations, we observed 7 haplotypes divided into 3 haplogroups, and 4 of those haplotypes were also observed in Europe. Our preliminary results did not show evidence of genetic structure in the native range, which did not allow to define the potential donor regions but the presence of several Asian haplotypes in Europe in addition to a low but significant geographical structure is in favor of multiple introductions. Nevertheless, more populations need to be sampled in the area of origin together with the definition of more polymorphic markers in order to better understand the invasion pathways of C. perspectalis.

Dryocosmus kuriphilus is a globally invasive insect pest, spreading very quickly in new habitats and making seriously damage to sweet chestnut forests in Croatia. Indigenous parasitoid species trophically associated with oak gallwasps have adapted to this new host but cannot effectively regulate its population density. Classical biological control using introduced parasitoid Torymus sinensis has been proven to be the only effective method of controlling the populations of D. kuriphilus. T. sinensis can successfully control the population density of D. kuriphilus, slowing down the spread and mitigating negative impact of this invasive chestnut pest and keeping the damage of D. kuriphilus at acceptable level. High specificity of T. sinensis suggests that it has limited potential of exploiting native hosts. In Croatia, during 4 years 15 species of native parasitoids have adapted to new invasive host but have no impact on lowering the population density. T. sinensis has been released in sweet chestnut forests in Croatia as promising biological control agent. Fusarium proliferatum induces larval mortality on D. kuriphilus and could be used in combination with native and introduced parasitoids for lowering high population densities of invasive D. kuriphilus.

Kestenova osa šiškarica (Dryocosmus kuriphilus ; Hymenoptera: Cynipidae) je strana invazivna vrsta i značajan štetnik na pitomom kestenu (Castanea sativa). Smatra se najznačajnijim štetnikom pitomog kestena u cijelom svijetu. U radu se opisuje kratka biologija ovog štetnika i biološko suzbijanje korištenjem parazitoida Torymus sinensis na području Pazin.

Jasenova grbica (Abraxas pantaria L.) poznata je kao defolijator jasena (Fraxinus spp.) na području Sredozemlja. U Hrvatskoj je 2001. zabilježena na području NP Krka gdje se hrani s lišćem poljskog jasena (Fraxinus angustifolia Vahl.), a s obzirom da je ovaj štetnik u Hrvatskoj ostao nepoznat isticala se potreba boljeg istraživanja biologije ovog štetnika. U sklopu istraživanja štetnika i bolesti na području NP Krka, u razdoblju od 2009. do 2012. godine praćene su štete koje je ovaj kukac činio na stablima poljskog jasena, te je utvrđeno da na području NP Krka jasenova grbica ne konzumira lišće crnog jasena (Fraxinus ornus L.). Krajem srpnja 2012. sakupljene su gusjenice koje su se u laboratoriju zakukuljile. Početkom kolovoza izlegli su se leptiri koji su kopulirali, te su ženke formirale jajna legla. Sredinom kolovoza počele su izlaziti nove gusjenice, te je u laboratorijskim uvjetima proveden pokus s ciljem utvrđivanja nekih karakteristika razvoja i palatabilnosti ovog štetnika. U laboratorijskim uvjetima gusjenice jasenove grbice imale su tri presvlačenje i prošle kroz 4 larvalna stadija, maksimalnu veličinu su dostigle četvrtog dana, a maksimalnu masu osmog dana od početka 4. stadija. Prosječno gusjenica u 4. stadiju konzumira između 0, 3329 – 0, 3673 grama svježeg lišća. Zamijećena je vidljiva razlika u larvalnom razvoju između muških i ženskih jedinki, koja se može primjetiti u 4. larvalnom stadiju kada ženke konzumiraju više lišća, dobivaju značajno više na masi, te su njihove kukuljice znatno teže. Jasenova grbica je dosad primjećena samo u NP Krka, ali zbog klimatskih odstupanja postoji mogućnost širenja na sjever Hrvatske.

Kestenova osa šiškarica (Dryocosmus kuriphilus) je invazivna vrsta kukca u cijelom svijetu i izuzetno brzo se širi u novom staništu. Smatra se jednim od najznačajnijih štetnika na pitomom kestenu (Castanea sativa). Autohtone vrste parazitoida koje su trofički vezane uz hrastove ose šiškarice (Cynipidae) su se prilagodile ovom novom invazivnom domaćinu, ali ne mogu učinkovito utjecati na smanjenje gustoće njegove populacije. Biološko suzbijanje koristeći unesenu vrstu parazitoida Torymus sinensis se pokazalo kao jedina učinkovita metoda kontrole populacije kestenove ose šiškarice, usporavajući njezino širenje i smanjujući štete na podnošljivu razinu. Visoka specifičnost parazitoida T. sinensis upućuje na ograničeni i nepostojeći potencijal iskorištavanja autohtonih domaćina. U Hrvatskoj se u 4 godine od pojave kestenove ose šiškarice na ovog novog domaćina prilagodilo 15 vrsta autohtonih parazitoida, ali oni nemaju nikakvog utjecaja na smanjenje gustoće njezine populacije. Zbog toga je u prirodne sastojine pitomog kestena u Hrvatskog ispušten uneseni parazitoid T. sinensis kao dokazano učinkovito sredstvo biološkog suzbijanja. U izlaganje se prikazuju rezultati uzgoja i ispuštanja parazitoida T. sinensis u Hrvatskoj.

Dryocosmus kuriphilus is a globally invasive insect pest, spreading very quickly in new habitats and making seriously damage to sweet chestnut forests in many European countries. Indigenous parasitoid species trophically associated with oak gallwasps have adapted to this new host but cannot effectively regulate its population density. Classical biological control using parasitoid Torymus sinensis (Chalcidoidea: Torymidae) has been proven to be the only effective method of controlling the populations of D. kuriphilus and has been successfully applied in Japan, South Korea, USA in the mid 1970th. It was introduced to Italy in 2005 and was released in several sites covering most of the infested area. In 2011 it was introduced and released in several sites in France. In 2013 Torymus sinensis was also introduced to Croatia and Hungary and was released into deciduous mixed forests with infested Castanea sp. The aim of this presentation is to provide overview and up-to date knowledge about biological control of D. kurphilus and to describe first steps of introduction of T. sinensis to sweet chestnut forests in Croatia and Hungary. The history and results of introductions of T. sinensis to Japan, South Korea, USA and Italy are shown as well as the adapted biology and behavioural traits of T. sinensis to its host D. kuriphilus are discussed. First results of T. sinensis release in France indicate that even though few biocontrol agents were released, the rate of establishment of T. sinensis is high (c. 80%). Although the parasitoid abundance was still low, the T. sinensis populations display a positive inter-annual growth rate. Possible negative effects of T. sinensis on native parasitoid fauna and risks that could influence the successful establishment of T. sinensis are discussed. Previous experiences have shown that T. sinensis can successfully control the population density of D. kuriphilus, slowing down the spread and mitigating negative impact of this invasive chestnut pest and keeping the damage of D. kuriphilus at acceptable level. High specificity of T. sinensis suggests that it has limited potential of exploiting native hosts but further detailed monitoring of native parasitoid and possible interactions with introduced T. sinensis is strongly suggested. The introduction of T. sinensis has raised some important questions to be further studied and answered: (i) the general risk that T. sinensis could shift to native gall wasps related to D. kuriphilus and (ii) could hybridize with native Torymus species. No other host than D. kuriphilus was ever mentioned in the literature to be parasitized by introduced T. sinensis. Till now, the only reported case of T. sinensis hybridization is with the native T. beneficus in Japan: T. sinensis and T. beneficus were successfully crossed in the laboratory to produce fertile hybrid females. The probability of hybridization with native European Torymus species was also tested, no mating was recorded yet in the laboratory experiments.

Brojne strane vrste kukaca unesene u zadnjih 200 godina su se uspješno udomaćile u različitim ekosustavima, i u Europi i u Hrvatskoj. Osnovna znanja o porijeklu, biologiji, načinu i vremenu unosa izuzetno su bitna kako bi se mogle procijeniti opasnosti od stranih vrsta. U Hrvatskoj je do sada utvrđena 101 strana vrsta fitofagnih kukaca i grinja (98 vrsta kukaca iz 6 redova i 3 vrste grinja iz podrazreda Acarina) na drvenastom bilju. Najzastupljeniji su redovi Hemiptera (56, 4%), Lepidoptera (14, 9%), Hymenoptera (12, 9%), a slijede ih Diptera (5, 9%), Coleoptera (5, 9%), Acarina (3%) i Thysanoptera (1%). Jedna trećina (33, 7%) stranih vrsta kukaca u Hrvatskoj potječe iz Azije, 26, 7% iz sjeverne Amerike dok je 12, 9% tropskog porijekla. Značajan porast broja unosa novih stranih vrsta kukaca godišnje u Hrvatskoj vidljiv je od 2007. do 2012. godine (6, 4 vrste/godini) u usporedbi s razdobljem od 2002. do 2007. (1, 8 vrsta/godini). Poljoprivredne površine su staništa na kojima se najčešće udomaćuju strane fitofagne vrste kukaca u Hrvatskoj (56, 4%), nakon njih su to parkovi i vrtovi (28, 7%) i šume (14, 9%). Sljedećih godina može se očekivati daljnji porast broja stranih vrsta fitofagnih kukaca u Hrvatskoj, a među onima koji se već nalaze nedaleko od granica Hrvatske nalaze se potencijalno opasni šumski štetnici. Globalizacija će sigurno i utjecati na rastući trend unosa i širenja novih stranih vrsta kukaca u Hrvatskoj što će se negativno odraziti na ekonomiju i ekosustave.

U radu se opisuje metoda biološkog suzbijanja kestenove ose šiškarice, nove invazivne vrste u Hrvatskoj. Važno je napomenuti da je ovo prvo istraživanje uzgoja i ispuštanja strane vrste parazitoida u šumarstvu u Hrvatskoj u svrhu biološkog suzbijanja. Biološkim se suzbijanjem želi smanjiti gustoća populacije, a time i štete nove invazivne vrste koja se intenzivno širi u novom staništu i čini ekološke i ekonomske štete. Parazitoidi su prvi puta ispušteni u području Istre gdje pitomi kesten (marun) ima, osim plodova, i bitno tradicijsko značenje za stanovnike tog kraja. Pitomi kesten ima višestruke općekorisne funkcije šume na području cijele Hrvatske koje nadmašuju vrijednost njegove drvne mase.