Many bark and ambrosia beetle species (Coleoptera: Scolytinae and Platypodinae) are known to have spread worldwide in relation to international trade. Concerns have been expressed within the European ...and Mediterranean Plant Protection Organization (EPPO) about recent introductions of non-indigenous species of these groups. Regulation of the non-coniferous wood trade into many EPPO member countries is currently not sufficient to cover such risks. In 2018–2019, an EPPO study on the risk of bark and ambrosia beetles associated with imported non-coniferous wood was carried out, and the key characteristics contributing to the pest risk from introduced species were determined using expert consensus. This paper summarizes the key findings of the study, which are available in full detail on the EPPO website. The study identified biological and other risk factors and illustrated them with examples from 26 beetle species or groups of species known to be invasive or posing a threat to plant health. These representative species were classified into three categories based on known damage and level of uncertainty. In the present article, factorial discriminant analyses were used to identify features of bark and ambrosia beetle biology associated with damage caused and invasiveness. Based on the information assembled and consideration of the risk factors, it was recommended that in order to prevent the introduction of new bark and ambrosia beetles via non-coniferous wood commodities, horizontal phytosanitary measures should be adopted, irrespective of the host plant species and the origin (i.e., for all genera of non-coniferous woody plants and from all origins). Phytosanitary measures are presented here for various wood commodities.
Bark beetle outbreak sites were analysed before sanitary logging in Gorski Kotar County during spring, summer and autumn 2021. Downed European silver fir trees were inspected for red-listed ...saproxylic entomofauna. Among other species, the fir pinhole borer (Treptoplatypus oxyurus, Dufour, 1843) (Coleoptera: Platypodidae) was observed and studied on-site and in the laboratory. Symptoms of T. oxyurus presence were recognised as white filamentous bites of sawdust on the bark of the fir trees and the surrounding soil. Every tree infested infested with T. oxyurus was measured (diameter at breast height, height/length), and its position was recorded. Segments were collected for laboratory analysis to evaluate the layout and position of T. oxyurus gallery system. The results showed that individual corridors of T. oxyurus, as a rule, never intersect, cross or connect. Each family of beetles (male, female and their offspring) lives separately in its corridor system. There were examples of corridors that were very close to each other but did not touch. T. oxyurus is still completely unknown to forest operatives in Croatia, who do not recognise symptoms of its occurrence.
The oak lace bug (OLB)
Corythucha arcuata
(Say, 1832) is an invasive alien species (IAS) that potentially could have many negative impacts on European oak health. Certain measures can be applied to ...counteract these effects. However, these measures may not be acceptable for forest managers or other stakeholder groups, such as private forest owners, environmental NGOs or the general public. Thereby, we set out to study the perception and knowledge of foresters and other stakeholders on the health status of European oak forests affected by oak lace bug and to investigate what forest health management measures would be acceptable to these target groups. An online survey questionnaire was designed and distributed via social networks, as well as professional networks via e-mails. The survey questionnaire was completed by 2084 respondents from nine European countries: Austria, Croatia, Belgium, France, Hungary, Italy, Romania, Serbia and Slovenia. Even though only a little over 60% of respondents reported they had noticed the discolouration of oak leaves caused by OLB, almost all (93%) considered it to be a problem. As respondents come from a country where
C. arcuata
is widespread and established, people’s general knowledge and awareness of OLB began to increase. The survey revealed that foresters thought that the insect affected photosynthesis, acorn crop and the aesthetics of the trees, but cannot cause death of trees. However, they assume that the value of the wood would decrease (this fact is also supported by the respondents who are connected to an environmental NGO), but that OLB does not affect property value. However, forest owners claim that the value of the property can be affected and that people would avoid entering the forest. In terms of potential control methods, respondents preferred biological or mechanical measures over chemical ones. We consider this study to be a good basis for further research on the topic of perception, knowledge and attitudes related to OLB since we can expect that the IAS, such as OLB, will certainly spread to European countries that were not included in this survey.
Boundaries between habitats are usually accompanied by transitions in the diversity and structural complexity of insect assemblages. Edge effects on carabid beetle assemblages across forest-meadow ...ecotones in Dinaric beech-fir forests were determined in the Gorski Kotar region of western Croatia. Embedded forest edges were greater than 100 years old and had a similar composition and structure of vegetation to that in the adjacent forest. A total of 20,526 individuals belonging to 66 carabid beetle species were recorded. Embedded forest edges reduced the microclimate edge effect by providing stable microclimatic conditions for carabid assemblages similar to those in the forest interior. In addition, this enabled forest specialists and generalists to occur right up to the forest edge and maintain stable populations in the ecotone. This study confirmed that the structure and ages of the vegetation at edges may play a key role in determining the spatial pattern of carabid beetles across forest-meadow ecotones.
The North American oak lace bug feeds on leaves of ‘white oaks” in its native range. In Europe, it was first discovered in northern Italy in 2000. In recent years, it has subsequently spread rapidly ...and population outbreaks have been observed in several European countries. In the present study, we summarize the steps of its expansion.
To predict its potential host range, we checked 48 oak species in 20 sentinel gardens in seven countries between 2013 and 2018.
In total, 27 oak species were recorded as suitable hosts; 13 of them are globally new ones, 23 out of the 29 in section Quercus (∼ white oaks, an intrageneric taxonomic unit within genus Quercus), including Asian oaks, native to Japan, Korea and China, and four out of five in section Cerris (another intrageneric unit of the same genus), were accepted as hosts. None of the species in section Lobatae (red oaks) or in the Ilex group was accepted.
Host records were also collected in forest stands of 10 countries. We found 11 oak species that were infested. Outbreak populations were most commonly found on Quercus robur, Quercus frainetto, Quercus petraea and Quercus cerris, comprising widespread and outstandingly important oaks species in Europe.
Based on our findings, we conclude that suitable hosts for oak lace bug are present in most of Europe and Asia. This means that a lack of hosts will likely not restrict further range expansion.
Geometrid outbreak waves travel across Europe Tenow, Olle; Nilssen, Arne C; Bylund, Helena ...
Journal of animal ecology,
2013, 20130101, January 2013, 2013-Jan, 2013-01-00, Volume:
82, Issue:
1
Journal Article
Peer reviewed
Open access
We show that the population ecology of the 9‐ to 10‐year cyclic, broadleaf‐defoliating winter moth (Operophtera brumata) and other early‐season geometrids cannot be fully understood on a local scale ...unless population behaviour is known on a European scale. Qualitative and quantitative data on O. brumata outbreaks were obtained from published sources and previously unpublished material provided by authors of this article. Data cover six decades from the 1950s to the first decade of twenty‐first century and most European countries, giving new information fundamental for the understanding of the population ecology of O. brumata. Analyses on epicentral, regional and continental scales show that in each decade, a wave of O. brumata outbreaks travelled across Europe. On average, the waves moved unidirectionally ESE–WNW, that is, toward the Scandes and the Atlantic. When one wave reached the Atlantic coast after 9–10 years, the next one started in East Europe to travel the same c. 3000 km distance. The average wave speed and wavelength was 330 km year⁻¹ and 3135 km, respectively, the high speed being incongruous with sedentary geometrid populations. A mapping of the wave of the 1990s revealed that this wave travelled in a straight E–W direction. It therefore passed the Scandes diagonally first in the north on its way westward. Within the frame of the Scandes, this caused the illusion that the wave moved N–S. In analogy, outbreaks described previously as moving S–N or occurring contemporaneously along the Scandes were probably the result of continental‐scale waves meeting the Scandes obliquely from the south or in parallel. In the steppe zone of eastern‐most and south‐east Europe, outbreaks of the winter moth did not participate in the waves. Here, broadleaved stands are small and widely separated. This makes the zone hostile to short‐distance dispersal between O. brumata subpopulations and prevents synchronization within meta‐populations. We hypothesize that hostile boundary models, involving reciprocal host–herbivore–enemy reactions at the transition between the steppe and the broadleaved forest zones, offer the best explanation to the origin of outbreak waves. These results have theoretical and practical implications and indicate that multidisciplinary, continentally coordinated studies are essential for an understanding of the spatio‐temporal behaviour of cyclic animal populations.
Better understanding of overwintering strategy in
Ips typographus
is crucial in planning of sanitation felling as hot spots recovery measure. Bark and needle litter are present as overwintering ...niches within the species. At the lowest elevation (500 m a. s. l.) in spruce stands 85 % of beetles overwinter under the bark. Overwintering behavior is elevation adaptable, and portion of beetles which overwinters under the bark of attacked trees increase with decreasing of elevation. The results suggest presence of high plasticity within the species which is well adaptable to changeable habitat and temperature conditions. High in the mountains sanitation felling need to be implemented early in autumn before beetles end the development, while at lower elevations a good result can be achieved with felling early in spring before the start of new generation. During the winter bark peels off the dense attacked tress very often and changes the beetle ratio between niches. This fact needs to be considered in planning of sanitation felling early in spring before fly period of
I
.
typographus
.
Pokus je postavljen u ljeto 2014. s ciljem boljeg razumijevanja strategije zimovanja smrekovog pisara, ali djelomično i zbog dopune zaključaka nedavno provedenih istraživanja (Hrašovec i dr., 2011). U kulturi smreke na nadmorskoj visini od 550 m. u mjesecu srpnju oboreno je 5 potpuno zdravih smrekovih stabala koja su okresana i ostavljena u sjeni okolnih stabala. Prva ubušivanja smrekovog pisara primijećena su već nakon tjedan dana. Početkom mjeseca siječnja 2015. godine stabla su izrezana u trupce dužine 4 m radi lakšeg prijevoza do skladišta gdje su u potpunosti analizirana. Svaki trupac podijeljen je u 4 sekcije dužine jedan metar, a na sredini sekcije izmjeren je srednji promjer zbog izračuna površine kore pojedine sekcije i samog trupca, odnosno stabla. Prije otkoravanja obilježeni su i prebrojani izletni otvori gdje je svaki izletni otvor predstavljao jednog odraslog potkornjaka koji je prezimio u tlu. Osim broja potkornjaka utvrđen je i broj prirodnih neprijatelja (
Thanasimus
(Coleoptera: Cleridae),
Medetera
(Diptera: Dolichopodidae), predatory gall midges (Diptera: Cecidomyiidae) koji prezimljavaju pod korom napadnutih stabla. Gledajući na razini same vrste kao mjesta prezimljavanja prisutne su dvije ekološke niše – tlo i kora. U smrekovoj kulturi na najnižoj nadmorskoj visini na kojoj smreka raste 85 % potkornjaka prezimljuje pod korom napadnutih stabala, dok na višim nadmorskim visinama postotak značajno opada. Rezultati ukazuju na vjerovatnost prilagodbe prezimljavanja promjenjivim stanišnim uvjetima i temperaturnim prilikama, što ponajprije proizlazi iz plastičnosti same vrste. Visoko u planinama sanitarna sječa treba se provesti krajem ljeta ili rano u jesen kada je većina potkornjaka još uvijek pod korom, dok se na nižim nadmorskim visinama dobri rezultati mogu se postići i sječom u rano proljeće prije leta potkornjaka. Ova mogućnost uvelike pomaže operativi na terenu, budući da često žarišta napada nije moguće sanirati u jesen, dijelom zbog nepristupačnog terena, a dijelom zbog nedostatka ljudi i mehanizacije. Kod primjene ovih rezultata operativa mora biti oprezna jer kora s napadnutih dubećih stabala tijekom zime otpada i mijenja odnos potkornjaka između niša zimovanja što izravno može utjecati na uspjeh planiranih sanacija u proljeće.
U prvom desetljeću 21. stoljeća u hrvatskim nizinskim hrastovim sastojinama proveden je niz istraživanja vezanih uz integriranu zaštitu hrastove oblovine. U središtu ovih istraživanja bila je ...olfaktorna manipulacija domaćim vrstama iz rodova Trypodendron i Xyleborus uz uporabu naletno-barijernih klopki kompletiranih s atraktantima (lineatin, ETOH, GLV, Domowit-Trypowit D®). Tijekom ovih eksperimenata u ulovima naletno-barijernih klopi, pojavila se nova vrsta za hrastove nizinske sastojine u Hrvatskoj Xylosandrus germanus. Pojava vrste Xylosandrus germanus u ulovima naletno barijernih klopki prvi puta je zabilježena u dijelu terenskih eksperimenta (2009. godine), a ulovi u naletno-barijernim klopkamasu bili su u porastu ostatak perioda provedenih istraživanja. Tijekom 2011. godine fenologija potkornjaka drvaša nizinskih hrastovih sastojina provedena je od siječnja do početka lipnja. U ovom periodu zabilježena je i praćena fenologija šest vrsta potkornjaka drvaša, od kojih je T. signatum bio najbrojniji, a invazivna strana vrsta X. germanus je bio drugi po brojnosti tijekom ovog opažanja, iako prisutan u ulovima naletno barijernih klopki 2011 godine. Iako je ekonomski značaj X. germanus malen, ovo je vrsta koja je prisutna u Europi 65 godina. Postoje zabilježeni slučajevi iz Švicarske 1995. g. kada je X. germanus napao 20 000 m3 smreke i jele u regiji Jura. S ekološkog gledišta, glavna zabrinutost je da X. germanus postaje jedan od najbrojnijih potkornjaka na područjima u kojima se etablirao, ali bez dokaza o negativnom utjecaju na autohtone vrste. Iako se smatra da X. germanus ima potencijal negativno utjecati na lokalno nestajanje autohtonih vrsta i biološku raznolikost (Henin and Versteirt 2004; Bouget and Noblecourt 2005). Istraživanja u Belgiji pokazuju da postoji preklapanje ekoloških niša X. germanus sa nekoliko autohtonih vrsta (Henin and Versteirt 2004). U Sjevernoj Americi , X. germanus je jedan od ekonomski najvažnijih negativnih čimbenika u rasadnicima. Neki autori navode da postoji izvjesna razina fiziološkog stresa koja nije uočljiva, ali stabla ipak emitiraju stresom generirane atraktivne tvari koje privlače potkornjake tijekom rojenja. X. germanus se smatra štetnikom koji napada fiziološki oslabljena stabla pod stresom, ali neka istraživanja pokazuju da napada i naizgled zdrava stabla. Prisutnost i brojnost X. germanus u Hrvatskoj još treba biti dodatno istražena, jer se ovaj polifagni štetnik uspješno razvija na velikom broju vrsta listača i četinjača. X. germanus isto može biti i vektor za određene uzročnike bolesti i najčešće se povezuje sa gljivama iz roda Fusarium, koje mogu uzrokovati odumiranje stabala, venuće i rak na napadnutim stablima. Ovakav vektorski odnos dokazan je na vrstama iz roda Juglans. X. germanus može prenositi i holandsku bolest brijesta. Zbog navedenog potrebno je daljnje praćenje i istraživanje utjecaja izrazito polifagne invazivne vrste potkornjak drvaša X. germanus na ekosustave nizinskih hrastovih sastojina.
During the first decade of 21st century in Croatian oak stands series of experiments concerning integrated oak timber protection were conducted. In the focus of this research was olfactory manipulation with native ambrosia beetles from genus Trypodendron and Xyleborus. Pheromone baited panel traps were used completed with different attractive components (lineatin, ETOH, GLV, Domowit-Trypowit D®) . During these experiments in trap catches new species of scolityd for Croatian lowland oak stands entomofauna was discovered. Occurrence of Xylosandrus germanus was first time registered in a second season of field experiments and its numbers had since continuously grown in trap catches. In 2011. monitoring of flight period for ambrosia beetles was conducted from beginning of January till early June. During this period six species of ambrosia beetles were caught among them most numerous species was T. signatum while X. germanus was second although only present in trap catches for four years.
Native narrow-leaved ash (
Fraxinus angustifolia
Vahl) and introduced green ash (
F. pennsylvanica
Marshall) are two most common ash (
Fraxinus
spp.)
species in Croatian lowland forests, taking
a ...significant place in these ecosystems. In the recent past it has been observed that narrow-leaved ash
seed yields have reduced, emphasising the importance of good health status of those collected, as they are used for seedling production and consecutive regeneration of forest stands or afforestation. Given that insects could be an important factor affecting ash seed health status, the aim of this research was to gain insight into the species being present and their frequency in the ash seeds. In total 2.500 narrow-leaved ash
and 1.000 green ash
seeds from seven different locations were screened for insect presence. Analysed seeds were categorized as undamaged, insect damaged or empty, and observed insect specimens were identified by morphological and molecular genetic analysis. Green ash
seeds revealed higher insect infestation in comparison with native ash species, with weevil
Lygniodes bischoffii
being the most numerous pest found. Narrow-leaved ash
seeds were mostly occupied by the native weevil species,
L. enucleator.
Besides these pests, larval, pupal, and adult stages of parasitoid wasps (Hymenoptera) and larval stage of the seed eating moth
Pseudargyrotoza conwagana
(Lepidoptera) were found in both ash species. However, given that pests detected in this study prefer urban areas or were present in a very small number of seeds, where they were often followed by parasitoids, it can be concluded that insects currently do not have a significant negative impact on the reproduction of narrow-leaved ash
and green ash in forest stands.
Autohtoni poljski jasen (
Fraxinus angustifolia
Vahl) i alohtoni pensilvanski jasen (
F. pennsylvanica
Marshall) su dvije najčešće vrste roda
Fraxinus
prisutne u nizinskim šumama Hrvatske, zbog čega zauzimaju važno mjesto u ovim šumskim ekosustavima. Posljednjih godina je zapaženo smanjenje uroda sjemena poljskog jasena, naglašavajući važnost dobrog zdravstvenog stanja sakupljenih količina, jer se sjeme koristi za proizvodnju sadnica koje se dalje upotrebljavaju za pomlađivanje šumskih sastojina ili pošumljavanje. Kako kukci mogu imati velik utjecaj na zdravstveno stanje sjemena, cilj ovog istraživanja je bio dobiti uvid u prisutne vrste i njihovu učestalost u sjemenu jasena. Prisutnost kukaca je analizirana u ukupno 2.500 sjemenki poljskoga i 1.000 sjemenki pensilvanskog jasena. Promatrano sjeme je kategorizirano kao neoštećeno, oštećeno i prazno (šturo), a nađene jedinke kukaca su identificirane na temelju morfoloških karakteristika i korištenjem molekularno genetičke analize. Sjeme pensilvanskog jasena pokazalo je veću oštećenost kukcima u usporedbi sa sjemenom poljskoga jasena, pri čemu je pipa
Lygniodes bischoffii
bila naj
č
e
š
ć
i utvr
đ
eni štetnik. O
š
te
ć
eno sjeme poljskog jasena je naj
č
e
š
ć
e bilo nastanjeno autohtonom vrstom pipe,
L. enucleator.
Osim navedenih štetnika, u sjemenu obje vrste jasena su na
đ
ene li
č
inke, kukuljice i imaga parazitoidnih osa (Hymenoptera) te ličinke štetnika
Pseudargyrotoza conwagana
(Lepidoptera). S obzirom da štetnici utvrđeni u istraživanju preferiraju urbana područja ili su nađeni na vrlo malom broju sjemena, često zajedno sa parazitoidima, može se zaključiti kako kukci trenutno nemaju značajan negativan utjecaj na zdravstveno stanje sjemena poljskog i pensilvanskog jasena u šumskim sastojinama.
The study was aimed at evaluating the influence of winter mortality and predator larvae abundance on breeding performance of bivoltine populations of Ips. typographus colonizing felled spruce trees ...in Croatia. A low colonization density of I. typographus expressed as a number of maternal galleries per square meter of bark, usually reflects high reproductive success, defined as a number of daughters per mother beetle (female/female). Regarding this study, the mean gallery density on felled trees varied between 27 and 146 per m(2) of bark, while the lowest reproduction rate was only 0.5 female/female. Althought differently suggested by previous findings, the cause of such a low reproduction rate can be explained by high abundance of predator larvae and high winter mortality of larvae, pupae and callow beetles. The results suggest that predators, primarily long-legged flies-of the genus Medetera (Fischer von Waldheim) (Diptera: Dolichopodidae), have huge ecological impact on bark beetle populations at endemic levels. At low attack densities, the majority of males (74%) copulate with two females, following the evolutionary trait of avoiding intraspecific larval competition.
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