Genetic variability and geographic structuration of gypsy moth (Lymantria dispar L.) in forests of Europe

Gubar je polifagni leptir rasprostranjen većim dijelom sjeverne hemisfere. Za gubara su karakteristične periodičke gradacije, a zbog polifagnosti i sposobnosti za longitudinalne i latitudinalne ekspanzije spada među najznačajnije biotske uzročnike poremećaja i šteta u šumama Europe, a štete se generalno povećavaju od zapada prema istoku i od sjevera prema jugu. Kompleksi prirodnih neprijatelja imaju izraženu ulogu u regulaciji brojnosti i na populacijsku dinamiku gubara, no genska raznolikost s druge strane značajno doprinosi sposobnosti prilagodbe i opstanka vrste. Pojava gradacija varira između različitih područja Europe, što potiče pitanje o genetičkim razlikama između populacija, a što je dodatno potkrijepljeno poznatim posljedicama Kvaternarnih glacijacija. Upotrebom COI mitohondrijskog DNA biljega analizirano je 497 jedinki sa 38 lokaliteta u Europi. Ustanovljena je općenito visoka genska raznolikost i značajna strukturiranost u 8 glavnih filogeografskih grupa. Rekolonizacijski obrazac gubara podudara se sa paradigmom leptir, pri čemu su Dinaridi djelovali kao barijera toku ilirskih gena. Populacije iz Gruzije posjeduju značajno različite haplotipove od ostatka Europe, no one u kontekstu predviđenih pomicanja areala gubara kao posljedice klimatskih promjena ne predstavljaju velik rizik. Međutim, ilirske populacije koje posjeduju najvišu gensku raznolikost, predstavljaju visok rizik u slučaju širenja u genski siromašne populacije koje nastanjuju visoko vrijedne šumske sastojine kontinentalnog bazena Balkanskog poluotoka.The gypsy moth is a polyphagous butterfly spread throughout the northern hemisphere. Gypsy moth has characteristic periodic outbreaks, and due to its polyphagous nature and capabilities for longitudinal and latitudinal expansion it is considered one of the significant biological agents causing disturbances and damage in forests of Europe. The damage is generally higher from west to east and from north to south. Complex of natural enemies play a strong role in the regulation of the gypsy moth population density and dynamics, but the genetic diversity on the other hand significantly contributes to the adaptive capacity and survival of the species. The outbreak occurence varies between different regions of Europe, which raises the question of possible genetic differences between populations, additionally supported by the known consequences of quaternary glaciations. Using the COI mitochondrial DNA marker, 497 specimens from 38 sites in Europe were analyzed. Generally high genetic diversity and significant structure of the 8 major phylogenetic groups was observed. Recolonisation pattern of gypsy moth is congruent with the butterfly paradigm, with Dinarid Alps acted as a barrier for the Illyrian genes. Populations from Georgia have significantly different haplotypes from the rest of Europe, but in the context of the predicted gypsy moth range shift as a result of climate change they dont represent a high risk. However, the Illyrian populations that possess the highest genetic diversity represent a high risk in the event of expansion in genetically poor populations in highly valuable forest stands of continental basin of the Balkan Peninsul

Genetic variability and geographic structuration of gypsy moth (Lymantria dispar L.) in forests of Europe

Gubar je polifagni leptir rasprostranjen većim dijelom sjeverne hemisfere. Za gubara su karakteristične periodičke gradacije, a zbog polifagnosti i sposobnosti za longitudinalne i latitudinalne ekspanzije spada među najznačajnije biotske uzročnike poremećaja i šteta u šumama Europe, a štete se generalno povećavaju od zapada prema istoku i od sjevera prema jugu. Kompleksi prirodnih neprijatelja imaju izraženu ulogu u regulaciji brojnosti i na populacijsku dinamiku gubara, no genska raznolikost s druge strane značajno doprinosi sposobnosti prilagodbe i opstanka vrste. Pojava gradacija varira između različitih područja Europe, što potiče pitanje o genetičkim razlikama između populacija, a što je dodatno potkrijepljeno poznatim posljedicama Kvaternarnih glacijacija. Upotrebom COI mitohondrijskog DNA biljega analizirano je 497 jedinki sa 38 lokaliteta u Europi. Ustanovljena je općenito visoka genska raznolikost i značajna strukturiranost u 8 glavnih filogeografskih grupa. Rekolonizacijski obrazac gubara podudara se sa paradigmom leptir, pri čemu su Dinaridi djelovali kao barijera toku ilirskih gena. Populacije iz Gruzije posjeduju značajno različite haplotipove od ostatka Europe, no one u kontekstu predviđenih pomicanja areala gubara kao posljedice klimatskih promjena ne predstavljaju velik rizik. Međutim, ilirske populacije koje posjeduju najvišu gensku raznolikost, predstavljaju visok rizik u slučaju širenja u genski siromašne populacije koje nastanjuju visoko vrijedne šumske sastojine kontinentalnog bazena Balkanskog poluotoka.The gypsy moth is a polyphagous butterfly spread throughout the northern hemisphere. Gypsy moth has characteristic periodic outbreaks, and due to its polyphagous nature and capabilities for longitudinal and latitudinal expansion it is considered one of the significant biological agents causing disturbances and damage in forests of Europe. The damage is generally higher from west to east and from north to south. Complex of natural enemies play a strong role in the regulation of the gypsy moth population density and dynamics, but the genetic diversity on the other hand significantly contributes to the adaptive capacity and survival of the species. The outbreak occurence varies between different regions of Europe, which raises the question of possible genetic differences between populations, additionally supported by the known consequences of quaternary glaciations. Using the COI mitochondrial DNA marker, 497 specimens from 38 sites in Europe were analyzed. Generally high genetic diversity and significant structure of the 8 major phylogenetic groups was observed. Recolonisation pattern of gypsy moth is congruent with the butterfly paradigm, with Dinarid Alps acted as a barrier for the Illyrian genes. Populations from Georgia have significantly different haplotypes from the rest of Europe, but in the context of the predicted gypsy moth range shift as a result of climate change they dont represent a high risk. However, the Illyrian populations that possess the highest genetic diversity represent a high risk in the event of expansion in genetically poor populations in highly valuable forest stands of continental basin of the Balkan Peninsul

The Role of Bark Beetles in Silver Fir Decline and Possible Use of Pheromone Traps for the Monitoring

Obična jela je najvažnija četinjača hrvatskog šumarstva, ali i najugroženija vrsta čije se sušenje odvija periodički. Novija jača sušenja jele događaju se od 2003. godine, posebiceo u Lici i Gorskom kotaru. Registriran je velik broj sušaca i jak napad jelovih potkornjaka. Gradacija potkornjaka uglavnom je vezana uz tri vrste roda Pityokteines koji dolaze u Hrvatskoj: P.curvidens,P. spinidensiP. vorontzowi. Cilj rada bio je utvrditi koliki utjecaj na sušenje jele imaju potkornjaci roda Pityokteines. U tu svrhu su na Litoriću u Gorskom kotaru postavljene feromonske klopke za monitoring, koji se provodio kroz vegetacijske periode od 2004. do 2010. godine. Uz monitoring u 2007. godini ispitivana je djelotvornost nekoliko sustava klopki: standardne/suhe i modificirane/mokre. Za potrebe istraživanja korišten je feromonski pripravak Curviwit® koji služi za primamljivanje jedinki jelovog krivouzubog potkornjakaP. curvidens. Kroz sedam godina monitoringa jelovih potkornjaka, jasno je utvrđena njihova povezanost sa količinom sušaca, pri čemu su najveći ulovi u kopkama utvrđeni između 2005. i 2007. godine. Tih je godina u šumama posječeno najviše sušaca jele. Većina ulova (94 %) kroz sve godine monitringa bila je u travnju i svibnju, te se zaključuje kako je klopke smisleno koristiti samo u tim mjesecima. Testirane su modificirane Theysohn klopke kod kojih se tehničkom preinakom onemogućila odvodnja tekućine iz posudice za ulov kukaca. Usporedbom ulova potkornjaka sa standardnom Thysohn® klopkom, modificirane su znatno više lovile. Na osnovi izračuna gustoće populacije potkornjakaP. spinidensiP. curvidensna uzorkovanoj kori, simuliran je biološki potencijal tih kukaca uz primjenu stope mortaliteta od 70 %, kao maksimalni mortalitet utvrđen u prethodnim istraživanjima. Na temelju toga pretpostavlja se da potkornjacima naseljeno devedesetogodišnje stablo jele izravno ugrožava 50-60 stabala u idućoj godini. Kako je biotički potencijal ovih vrsta potkornjaka izrazito visok, smisleno je u svrhu redukcije populacije uspostaviti monitoring sustav feromonskim klopkama, a na temelju dobivenih rezultata provoditi preventivne- sanitarne mjere zaštite šuma.Silver fir is the most important coniferous species in Croatian forestry, but in the same time the most threatened whose strong decline occurs periodically.Recent decline in Croatia was registered in the year 2003, especially in Lika and Gorski Kotar, with strong attack of fir bark beetles.This beetle gradation is connected with the three known Pityokteines species in Croatia: P. curvidens, P. spinidensandP. vorontzowi.The aim of this work was to determine what impact bark beetles have on the decline of Silver fir.For this purpose pheromone traps were placed in Litoric (Gorski Kotarmiddle Croatia), for monitoring through the vegetation periods from 2004to 2010. In addition, in 2007the effectiveness of different trap systems was tested. The commonly used Theysohn trap with dry container was modified through locking the container so liquid that was previously put in it couldn’t efflux. A pheromone mixture named Curviwit ® was used which is used for individuals baiting of fir bark beetle species Pityokteines curvidens. The results during the seven year monitoring period show clearly visible connection between fir bark beetles and fir decline (Figure 1). The largest catches in pheromone traps were measured between 2005 and 2007,when the most injured trees were felled in the forests.Most catches, about 94 %, throughout the year of monitoring occur in April and May (Figure 2 and 3), which concludes that traps should be placed only in those months. The test results of dry versus wet traps show that more important catch is achieved by modifying Theysohn traps to wet traps (Figure 4). On the basis of calculating the abundance of bark beetles ofP. spinidens andP. curvidensin the trunk (Table 1) and the use of maximum mortality rates of 70 %, from previous studies biological potential of these insects was simulated.One infected 90 year old fir tree is directly threatening 50-60 trees in the next years.This result demonstrates the enormous potential of the silver fir bark beetle species. Because of the need to reduce the population of bark beetles, use of pheromone traps for monitoring should be considered as one action for effective preventive and sanitary measures in protection of forests

POSSIBILITY OF USING ENTOMOPATHOGENIC FUNGI BEAUVERIA BASSIANA FOR CONTROLLING THE ASH WEEVIL (STEREONYCHUS FRAXINI)

Jasenova pipa spada među najopasnije štetnike jasena, a štete čini i na drugim vrstama. Dosadašnje suzbijanje svodi se na primjenu kemijskih pesticida u stadiju ličinke. Kako se primjena kemijskih pesticida ograničava, prednost se daje pripravcima na biološkoj bazi. Entomopatogena gljiva Beauveria bassiana u znatnoj mjeri napada prezimljujuća imaga jasenove pipe, a pozitivni rezultati ispitivanja na drugim vrstama iz porodice pipa (Curculionidae) opravdavaju istraživanja mogućnosti primjene ove gljive za suzbijanje jasenove pipe. Ovim istraživanjem htjelo se utvrditi potencijal B. bassiana kao biološkog sredstva za suzbijanje jasenove pipe. S tim u svezi uspoređena je efikasnost eksperimentalnog soja BB1 iz Mađarske i autohtonog soja dobivenog iz uginulih zaraženih imaga iz Lipovljana. Pokus s eksperimentalnim sojem BB1 iz Mađarske nije pokazao utjecaj na mortalitet imaga, dok je pokus kontaminacije sporama s uginulih zaraženih imaga iz Lipovljana pokazao ugibanje 83 % imaga jasenove pipe od mikoze koju je uzrokovala B. bassiana. Ujedno je ojačana pretpostavka o koevolucijski razvijenom soju gljive patogenom za lokalne populacije kukca te utvrđen potencijal gljive B. bassiana kao biološkog sredstva za suzbijanje jasenove pipe. Daljnja istraživanja treba usmjeriti prema masovnoj proizvodnji spora i terenskom ispitivanju u šumi.Ash weevil (Stereonychus fraxini) is one of the most dangerous pests of ash, it also damages olives, and some other tree species. So far, suppression has been conducted by mainly using chemical pesticides during the developmental stages of larvae, which has not prevented major damage resulting from beetles (regeneration devouring?). Because of environmental concerns, the use of chemical pesticides is restricted and development of selective biological pesticides is proposed. A significant effect of the entomopathogenic fungi Beauveria bassiana on overwintering adults of ash weevil, together with the positive results of tests on other species of the weevil family (Curculionidae), suggest that the possibility of applications of the fungus to control ash weevil should be studied. This study was carried out in order to determine the potential of B. bassiana as a biological agent for the control of ash weevil, and to compare the efficacy of an experimental strain BB1 from Hungary and native, yet undefined, strain from fungus-infected dead beetles from Lipovljani. Trial with the experimental strain BB1 from Hungary showed no effect on mortality of adults, while contamination by spores from dead infected beetles from Lipovljani showed a significant effect on mortality caused by the entomopathogenic fungi (83%). This strengthened the assumption of the coevolutionary developed strain of fungi, pathogenic for the local population of insects and strengthened the potential of B. bassiana as a biological control agent to control ash weevil

First Record of Cacopsylla pulchella (Hemiptera, Psyllidae) in Croatia

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

Testing of biological effectiveness of pheromones and traps for catch of mediterranean bark beetle Orthotomicus erosus (Coleoptera, Curculionidae)

U šumama alepskog bora na hrvatskom Mediteranu u 2017. godini pojavio se mediteranski potkornjak (Orthotomicus erosus) u gustoćama populacije koje do tada nisu zabilježene te se nikada prije nije smatrao značajnim štetnikom na tom području. Naglo povećanje populacije potkornjaka prirodni neprijatelji nisu u stanju pratiti, a ishod je naglo povećanje sušaca. U sklopu mjera zaštite za suzbijanje mediteranskog potkornjaka u 2018. godini u Hrvatskoj su postavljene feromonske klopke u svrhu monitoringa. Iako postoji više mogućnosti primjene različitih vrsta klopki i feromonskih pripravaka za mediteranski potkornjak, do sada nije istraženo koja je razlika u ulovima različitih vrsta klopki niti koliko su selektivne. U 2019. godini na području Park šume Marjan (Split) na 196 ha šumske površine postavljeno je 40 feromonskih klopki. Uspoređeni su parovi feromonskih pripravaka Pheroprax i Erosowit, sustav triju klopki Triplet sa običnom naletno barijernom klopkom te modificirana klopka sa mokrim ulovom i obična naletno barijerna klopka. Osim prosječnog broja ulova u feromonskim klopkama posebna pozornost dana je selektivnosti. Od predatora u klopama su značajnije su nađene dvije vrste, Tanasimus formicarius i Temnochila caerulea, s tim da je T. formicarius u odnosu na T. caerulea bio u zanemarivim količinama. Rezultati ukazuju kako pripravak Erosowit u odnosu na Pheroprax pokazuje značajno veće ulove, te je značajno selektivniji. Pheroprax ima vrlo visoke ulove predatora T. caerulea te se ne preporuča za praktičnu primjenu. Triplet je u odnosu na običnu naletno barijernu klopku pokazao tek neznatno bolje ulove, ali i nešto bolju selektivnost. Triplet nije pokazao očekivani učinak s obzirom na količinu ulova koja je bila nešto viša u odnosu na običnu klopku, ali ne značajnije kako bi se preporučila njihova primjena. Mokra varijanta klopke pokazala se lošom, jer ne donosi signifikantno veće ulove od obične naletno barijerne klopke, a dvostruko manje je selektivna. S obzirom na dodatne troškove (adaptacija klopke, tekućina koja se mora mijenjati, sporije sakupljanje) ovaj tip klopke nije preporučljiv za primjenu. Usporedbom ukupnih prosječnih ulova mediteranskog potkornjaka 2018. i 2019. godine utvrđeno je da je broj potkornjaka u 2019. gotovo 5 puta manji u odnosu na 2018.In the Aleppo pine forests at the Croatian Mediterranean in 2017, a Mediterranean bark beetle (Orthotomicus erosus) appeared in population densities that had not been recorded before and until then was not considered a significant pest in that area. Natural enemies are not able to follow a sudden increase of the bark beetle population, which results in rapid increase of drying trees. As a part of the suppression of the Mediterranean bark beetle in 2018, pheromone traps have been installed in Croatia for monitoring purposes. Although there are multiple options for applying different types of traps and pheromone preparations for the Mediterranean bark beetle, so far the differences in catches of different types of traps and their selectivity have not been investigated. In 2019, 40 pheromone traps were placed in the Forest Park ​​Marjan (Split) on 196 ha of forest area. A pairs of pheromone preparations Pheroprax and Erosowit were compared, a system of three traps (Triplet) with a single flight barrier trap as well as the modified wet flight barrier trap with a regular flight barrier trap. In addition to the average number of catches in pheromone traps, particular attention was given to selectivity. Two predator species Tanasimus formicarius and Temnochila caerulea were found in traps, with T. formicarius in insignificant quantities relative to T. caerulea. The results indicate that Erosowit exhibits significantly higher catches compared to Pheroprax and is significantly more selective. Pheroprax has a very high catches of T. caerulea predators and is not recommended for practical use. The Triplet had only slightly better catches compared to the single flight barrier trap, but also showed slightly better selectivity. The Triplet did not show the expected effect due to the amount of the catch, which was slightly higher than in the single trap, but not significantly in order to recommend their use. The wet flight barrier trap turned out not to be satisfactory as it does not produce significantly higher catches than a regular flight barrier trap, and is twice less selective. Given the additional costs (trap adaptation, fluid that needs to be changed, slower collection), this trap type is not recommended for use. Comparing the results of the catch in 2019, the number of bark beetles was found to be almost 5 times lower than in 2018

Tachinid (Diptera: Tachinidae) parasitoids of spotted ash looper (Abraxas pantaria) in Krka National Park in Croatia

Background and purpose: Spotted ash looper, Abraxas pantaria (Lepidoptera: Geometridae) causes defoliations of narrow-leaved ash (Fraxinus angustifolia) in Croatia, mainly in Krka National Park. Since controlling pests with insecticides is not possible in protected areas, biological pest control might be a valuable option. The first step in the study of its application is the research on hosts and their natural enemies. Not much is known about the parasitoid spectrum of A. pantaria in Croatia, so the aim of this research is to identify the parasitoid species which could influence the population density of this potential forest pest. Materials and methods: Pupae of A. pantaria were studied in 2010 at several locations along the River Krka in Krka National Park. This area was chosen because total defoliation of ash was observed in 2010. Results and conclusions: Five tachinid species were reared from Abraxas pantaria: Phryxe nemea, Bactromyia aurulenta, Senometopia sp., Pales pavida and Eurysthaea scutellaris. All species are generalist parasitoids. Phryxe nemea is the first record for this host

Outbreak of Orthotomicus erosus (Coleoptera, Curculionidae) on Aleppo Pine in the Mediterranean Region in Croatia

Background and Purpose: Orthotomicus erosus, Mediterranean pine engraver, is widely distributed across the Mediterranean and southern Europe, Asia and North Africa. It is considered as secondary pest found on recently dead or felled trees, but can also attack weakened living trees. In high population levels this species can attack healthy trees and cause their dieback. Severe outbreaks occur after dry periods, or after fire in adjoining stands in warmer parts of the Mediterranean region, while this scenario has never happened in Croatia up to now. Bark beetles are important forest pests which have already been researched and discussed in relation to climate change, indicating that the predicted increase in temperature would lead to higher survival rates and faster development, thus directly influencing their population dynamics. Increase in temperature may stimulate changes in insects’ rate of development, voltinism, population density, size, genetic composition, extent of host plant exploitation, longitudinal and latitudinal distribution. Since climate conditions might have changed in the last few years as predicted in the Mediterranean region, the aim of our research is to document the first outbreak with high population levels of O. erosus in Croatia. Materials and Methods: The extent of dieback was evaluated by counting trees with dieback symptoms on diagonal transects plotted through each of 33 forest management sections of Marjan Forest Park (Split). Trunk sections from several trees with early stage symptoms were collected for further laboratory analysis, which consisted of incubation phase and subsequent morphological identification. During regular yearly surveys in forests of Croatia, the pest was observed on several sites and damages were recorded for both years 2017 and 2018. The records were entered into a map using QGIS version 3.2.1-Bonn. Spatial data was downloaded from DIVA-GIS server. Monitoring efforts were initiated in affected areas where 13 flight barrier pheromone traps (Theyson®) equipped with pheromone lure Erosowit® (Witasek, Austria) were set-up in late March in state-owned and privately owned forests across Dalmatia. Catches in the traps were collected and O. erosus adults were counted on a weekly basis in order to identify the abundance of the pest in monitored sites, as well as to obtain the first information about population dynamics and to assess voltinism. Results: On-site survey and the evaluation of dieback extent included sampling of 5% of all trees in Marjan Forest Park ,and the results showed that 23% of all trees in the forest park were affected by dieback symptoms. Visual examination of trunks, branches and bark showed symptoms of bark beetle infestation, while preliminary on-site examination of the observed adults pointed out to O. erosus. After two weeks in controlled conditions, bark beetle adults started to emerge from trunk sections which were placed in several mesh cages for incubation. Morphological identification by using stereomicroscope and the key for European bark beetles resulted in identification of O. erosus species. Over the course of the year 2017 one more site was reported to be infested with O. erosus, and eight additional sites were reported over the course of year 2018. In total, 446 ha were reported as infested, varying in intensity, in several different management units of state-owned and privately owned forests. The total number of trapped beetles in pheromone traps varied largely among sites. Our data indicate that several generations (at least 5 generations per year) were present in the year 2018. Conclusions: Sudden surge in observed damages, as well as the number of beetles trapped during monitoring, in years 2017 and 2018 throughout Aleppo pine forests in Dalmatia are the first record of O. erosus outbreak in Croatia. O. erosus is native to Croatia and so far it has been considered only as a minor pest whose outbreaks have never been recorded. Drought intensity and frequency and aridification trends in the research area (Dalmatia, Croatia) cause cumulative stress to trees and have increased O. erosus occurrence. O. erosus is expected to exhibit increased voltinism, better overwintering performance and earlier spring flights. Our first results confirm this epidemic stage of O. erosus with high abundances in Dalmatia in 2018 and at least 5 generations per year, which alter the population level of this pest. Finally, with high dispersal abilities of O. erosus through active flight and easy transportation with infested material (logs and branches with bark), O. erosus has the potential to become an important forest pest in Croatia. Thus, extensive studies on its biology, ecology, natural enemies and interaction with ophiostomatoid fungal species are needed in order to predict further spread and suggest viable and effective management measures

Adapted VTA and SIA method in tree static assessment with use of resistography

Background and Purpose: This paper introduces a method for assessment of static safety by using the combination of adapted VTA and SIA methods and a resistograph. The aim is to assess the static as reliably as possible and without the need for expensive equipment. The purpose of this paper is to propose amethod for the static assessment which could be applied in practice in the future. Materials and Methods: Seven trees in the Botanical Garden of the Faculty of Science (University of Zagreb) were selected for the assessment of vitality and static safety. It has been detected that those trees were affected by possible indicators of decreased vitality, such as fungi fruiting bodies on the root collar or trunk, dead branches, growthmalformations, burrs, dead bark etc. The selected trees were: Fagus sylvatica L. »Purpurea Tricolor«, Fraxinus pennsylvanica Marshall, Acer pseudoplatanus L. »Leopoldii«, Fagus grandifolia Ehrh., Quercus petraea L., Quercus phellos L. and Salix alba L. The static stability of the said trees was assessed using a combination of the following three methods: i) adapted VTA (Visual Tree Assessment) method; ii) SIA (Static Integrated Assessment) method; iii) resistograph measurement using IML-Rezi F-300.The height of each treewasmeasured using the Vertex device, while their diameters were measured using a measuring band. The trees were examined for external symptoms indicating their vitality. The crowns were observed using the Pentax XCF (12x50) binoculars. Afterwards, based on the basic data on the trees, the minimum thickness of sound wood (SW) necessary to maintain the static safety was determined using a computer program. The obtained data were then used to determine the manner in which and the place where the diagnostic instruments shall be used. Results and Conclusions: Based on the knowledge of the subject trees and themeasurement of their diameters and heights, SW, as well as the basic safety of trees was determined using the SIA method which was 140% to 410%. For all selected trees, the required safety was 100%, so SWminimum requirement for intact wood ranged from4.4 cmfor themaple to 9.4 for the oak. The resistograph measurements of the 7 assessed trees established that four complied with the requirements, while the American ash, the white willow and the sessile oak were decided for cutting down. The decision was made based on the median measured values, which were below the threshold determined by the SIA method. The sessile oak demonstrated the highest non-compliance, since it scored only 37.0% of the value required for intact wood. The willow scored 48.7%, while the ash scored 62.5%. The results of the resistograph measurement were compared to the r/R ratio. Those results show that there was no difference between the two methods, although the weak point of r/R ratio could be clearl

Spatial Distribution, Genetic Diversity and Food Choice of Box Tree Moth (Cydalima perspectalis) in Croatia

Background and Purpose: Box tree moth (Cydalima perspectalis: Lepidoptera, Crambidae) is an invasive species rapidly spreading through Europe and making considerable damage to native and planted European box plants (Buxus sp.). It has up to three generations per year and has no natural enemies in Europe which helps it to spread rapidly and to become highly invasive in its new range. The aim of this paper is to show i) spatial distribution, ii) number of generations; iii) food choice, and iv) genetic distribution of box tree moth in Croatia. Materials and Methods: Occurrence data of box tree moth were obtained by field observation and data obtained from the general public. The number of generations of box tree moth was studied by direct observation of life stages on plants. Food choice test was conducted on Buxus sempervirens, Ilex aquifolium, Euonymus japonicus and Ligustrum vulgare used as food plants. Haplotype diversity and distribution of box tree moth was done for 5 localities in Croatia and their comparison to the haplotypes from China, Korea and 10 European countries. Results: Box tree moth has rapidly spread over the whole territory of Croatia in 4 years and it has three generations per year. The larvae showed a clear preference for B. sempervirens leaves and the total consumption was 0.5 g/dry weight of box leaves/larva. Three haplotypes were observed and haplotype HT4 was found in 4 out of 5 sampling sites in Croatia. The haplotypes observed in Croatia were present in China, which indicates Chinese origin of Croatian populations. Conclusions: Suitable European climate, widely available host plants and lack of natural enemies have enabled box tree moth to become highly invasive, to quickly disperse in its new environment and to make devastating damages to ornamental European box plants and hedges