•In overwintering population of Corythucha arcuata there is a mortality rate of 65%.•Out of 19% fungal infections found, 70% belonged to Beauveria pseudobassiana.•Naturally occurring B. ...pseudobassiana is effective against C. arcuata.•One fungal isolate can produce 18% higher mycosis value than the other.
The invasive oak lace bug Corythucha arcuata (Say, 1832) (Hemiptera: Tingidae) was first recorded in lowland stands of pedunculate oak (Quercus robur L.) in Eastern Croatia in 2013, from where it expanded to the west causing summer yellowing and intensive chlorotic damages of oak leaves. In 2018, the entomopathogenic fungus Beauveria pseudobassiana Rehner and Humber (Hypocreales: Cordycipitaceae) was isolated from several dead C. arcuata adults found in moss, a typical place for overwintering. The first aim of this study was to estimate the number of overwintering adults per m2 of moss, their natural mortality, and natural infestation by this fungus. Moss and oak lace bugs were collected from oak trees at six different locations in infested forests in Spačva basin. C. arcuata individuals were counted and separated for further analysis and determination of possible fungal infections. Results demonstrated a high rate of mortality among overwintering individuals (65%), with 19% of them infested by various entomopathogenic fungi, of which 70% belonged to B. pseudobassiana. The second aim of this study was to test fungal virulence against C. arcuata under laboratory conditions and to study differences between the isolates. A suspension of conidia (concentration: 1 × 108 conidia/ml) was sprayed on healthy adults of C. arcuata on moss patches. Results showed no difference in mortality rates between the isolates (96–97%), but one isolate produced a mycosis of 49% compared to 32% of the other isolate, with 4% of mycosis in control. The results presented here demonstrate this fungus as an antagonist, and indicate it as a potential candidate for future biological control of this invasive pest.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Oak lace bug
Corythucha arcuata
represents a new pest of oaks in Europe, introduced from North America in year 2000. Damage is caused by adults and larvae that feed on the underside of leaves. The ...paper presents the results of investigation of impact of
Corythucha arcuata
on pedunculate oak growth. The two variant experiment was established in 2019 and included the evaluation of the effect of oak lace bug on the height of the seedlings (i) grown under the shade of the adult trees after the intermediate felling and (ii) seedlings grown unshaded after the final felling. Both variants included eight plots of which four were treated with the insecticide thiamethoxam, while other four were untreated. Assessment of the intensity of the attack was performed in June, July and August in 2019, 2020 and 2021, while the height of the plants was measured at the end of the vegetation period in 2019, 2020 and 2021.The results indicate significant decrease in the intensity of the attack on seedlings grown unshaded by the old trees. After first year, there was no difference in average height of the treated and untreated seedlings grown after the intermediate felling, while the difference was evident after second and third year. Such results indicate cumulative effect of the oak lace bug attack on the seedlings of the penduculate oak. On the other hand, during whole experiment, the differences between treated and untreated plant average height after the final felling were not evident.
Hrastova mrežasta stjenica
Corythucha arcuata
novi je štetnik hrastova u Europi, unešena je 2000. godine iz Sjeverne Amerike. Štete uzrokuju imago i ličinke koje se hrane sišući biljne sokove s donje strane lišća. U radu je analiziran utjecaj hrastove mrežaste stjenice na rast mladih hrastovih biljaka. Pokus je postavljen u ožujku 2019. u dvije varijante, od kojih je prva bila praćenje utjecaja napada stjenice na prosječnu visinu podmlatka hrasta lužnjaka na površini sa završenom oplodnom sječom, odnosno u sjeni djela stare šume koji ostaje za dovršnu sječu, a druga je bio praćenje utjecaja napada stjenice na prosječnu visinu podmlatka koji je rastao na otvorenom prostoru (Slika1,2). U obje varijante pokusa na četiri pokusne površine je uporabljen insekticid tiametoksam radi suzbijanja hrastove stjenice, a preostale četiri nisu tretirane, već su bile izložene napadu stjenice. Procjene intenziteta napada hrastove stjenice provedene su krajem lipnja, srpnja i kolovoza 2019., 2020. i 2021. godine. Mjerenje visine tretiranih i netretiranih biljaka u obje varijante pokusa obavljeno je na kraju vegetacije 2019, 2020 i 2021. godine.Istraživanja su pokazala znatno manji intenzitet napada hrastove stjenice na podmladak hrasta koji je rastao na čistini u odnosu na podmladak ispod starih stabala hrasta lužnjaka (Slika 3). U prvoj godini nije bilo značajnih razlika u prosječnoj visini tretiranih i netretiranih mladica u sjeni, ali su značajne razlike uočene nakon dvije i tri godine, što ukazuje na kumulativni učinak napada stjenice na visinu hrastovog podmlatka (Slike 6,7,8). Tijekom trogodišnjeg istraživanja nisu utvrđene značajne razlike u prosječnoj visini biljaka između tretiranih i netretiranih pokusnih ploha na otvorenom, što je rezultat značajno slabijeg napada stjenica na čistini. Podmladak hrasta lužnjaka na čistini je puno viši od podmlatka u sjeni starih hrastova, što je izravan utjecaj svjetla na biljake. To ukazuje da je s obzirom na manji intenzitet napada hrastove stjenice i brži rast biljaka pri punoj svjetlosti, povoljnije izvršiti obnovu na čistini ili je potrebno obaviti dovršnu sječu prije pojave hrastovog podmlatka. Podmladak hrasta lužnjaka koji se razvija ispod stabala stare sastojine nakon oplodne sječe potrebno je zaštititi od stjenice dok je u sjeni.
Early detection is important for the management of invasive alien species. In the last decade citizen science has become an important source of such data. Here, we used opportunistic records from the ...“LIFE ARTEMIS” citizen science project, in which people submitted records from places where they observed tree pests, to understand the distribution of a rapidly-spreading forest pest: the oak lace bug (
Corythucha arcuata
) in Slovenia. These citizen science records were not distributed randomly. We constructed a species distribution model for
C. arcuata
that accounted for the biased distribution of citizen science by using the records of other tree pests and diseases from the same project as pseudo-absences (so-called constrained pseudo-absences), and compared this to a model with pseudo-absences selected randomly from across Slovenia. We found that the constrained pseudo-absence model showed that
C. arcuata
was more likely to be found in east, in places with more oak trees and at lower elevations, and also closer to highways and railways, indicating introduction and dispersal by accidental human transport. The outputs from the model with random pseudo-absences were broadly similar, although estimates from this model tended to be higher and less precise, and some factors that were significant (proximity to minor roads and human settlements) were artefacts of recorder bias, showing the importance of taking the distribution of recording into account wherever possible. The finding that
C. arcuata
is more likely to be found near highways allows us to design advice for where future citizen science should be directed for efficient early detection.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Corythucha arcuata
(Hemiptera; Tingidae), i.e. oak bug is an invasive alien species from North America that has rapidly spread in Europe. It was first reported in Croatia in 2013, and in the ...following years it has spread rapidly toward the west of the continental part of the country, infesting 200,000 ha of
Quercus robur
L. forest stands. Oak lace bug causes losses in chlorophyll, which has a negative influence on photosynthesis and transpiration activity, as well as on the health status of oak trees. We conducted our study on two sites in the Mediterranean region in Istria, Croatia, where infestation with oak lace bug has not been recorded. Results showed new records of oak lace bug in Istria.
Q. pubescens
Willd. is the dominant tree species in Sub-Mediterranean forests in Istria, so it will be interesting to follow the spread and preferences of oak lace bug for
Q. robur
and
Q. pubescens
in Istria, as well as in other coastal
Q. pubescens
and
Q. ilex
L. forests in Croatia. We assume that the negative influence of oak lace bug coupled with other biotic and abiotic stressors in the Mediterranean region will probably have some influence on the health status of oak trees.
In the context of globalization, the biological invasions affect all the countries, including Romania, where this phenomenon is increasingly visible in the last years. Besides the invasive forest ...insects already known to be established in Romania, a new species - Corythucha arcuata (Say, 1832), commonly known as the oak lace bug and originating in North America, appeared in the last years. It was reported for the first time in Romania in 2015, and it spread across the country in 2016-2017. In order to detect the species and to draw its distribution area, a species identification sheet, as well as a working protocol were developed, considering the insect morphology and the type of attack. During the vegetation seasons 2016 and 2017, the species was found in 67 out of the 124 surveyed locations, mainly in the southern and western parts of the country, but also in the eastern part. The main host species of the oak lace bug were Quercus robur, Q. petraea, Q. cerris, Q. frainetto, and Q. pubescens. It attacked the host trees in all habitats (tree stands, parks, nurseries, isolated trees etc.) and the intensity of attack varied from 1% to 100% of the leaves.
Oak lace bug (
has caused increasing damage throughout Europe since its appearance in 2000. In Hungary, it has become a dangerous pest of
species in recent years. They frequently appear on ornamental ...and fruit trees, either, but this type of damage is not significant.
species are known as their common host plants in their native area, but in Europe, it was detected only in Bulgaria. In this paper, we provide the first record of oak lace bug on sweet chestnut (
) in Hungary, which represents only the second European data on
species. The pest was found in Debrecen, East Hungary.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This scientific paper examines the impact of climate change on the spread and survival of the invasive species Corythucha arcuata Say, 1832 (oak lace bug, or OLB) in Romania. The OLB is native to the ...Eastern USA and Canada, and in its native habitat, it coexists with minimal impact to the preferred host plant species Quercus. However, in Europe, the OLB in high density causes early defoliation, slowing tree growth. As Quercus spp. is a keystone species, the impact of the OLB on European forests is significant. This paper aims to address several gaps in knowledge about the OLB by presenting findings from a study conducted by the Lucian Blaga University of Sibiu (ULBS) in Romania. The study identified the species’ chronology of spread, ecology, ethology and biology of the species, in addition to foliage classification to determine the extent of attack. The study found a direct link between the temperature and the speed of the generational lifecycle. The findings support the thesis that climate change is enabling the healthy, rapid density growth of OLB, which is a danger to the Quercus spp. Further research is needed in the area of the thermal tolerance of the OLB, and the research conducted by the ULBS represents the first documented research into the thermal constant of the insect. The paper concludes that further research must be in the direction to understand how and where these insects survive during winter to find future management measures and identify chemical or biological methods as solutions to eradicate and stop the expansion of the invasion of the OLB, and the potential consequences for the Quercus sp.
In addition to the classic biotic and abiotic factors that have disrupted the health of forests throughout history, lately, the balance of forest ecosystems has been disturbed by different phenomena ...such as climate change, pollution, and, especially, biological invasions of invasive alien species. One of the alien species that has invaded Europe relatively quickly is an insect species of North American origin, the oak lace bug (Corythucha arcuata Say, 1832 Heteroptera: Tingidae). In the context of the rapid spread of infestations and the severity of attacks on oak trees in infested forests, this paper aims to assess measures to manage this species in the future. Namely, the effect of aerial chemical treatments on oak lace bug has been investigated with two influencing factors: the mode of insecticide action (contact and systemic) and the treatment volume (low volume and ultra-low volume). The experiment was conducted in two forests over a total area of 350 hectares. The results show that the reduction of the nymph population varied from 91% to 96%. However, the residual population was sufficient to allow differentiated re-infestations over time, more quickly after contact insecticide sprays (22 days after treatment) and slowly after systemic insecticide sprays (more than a month after treatment). This re-infestation time difference had implications on attack intensity as well, with stronger leaf discoloration observed in areas treated with a contact insecticide compared with those treated with a systemic insecticide.
To control a forest pest, it is necessary to understand the biotic and/or abiotic factors that can lead to population regulation. Such knowledge is even more critical if the pest is an invasive alien ...species. This is the case for Corythucha arcuata (Say, 1832), commonly known as the oak lace bug (OLB), an alien insect species that has invaded oak forests on a large scale, both in Romania and other European countries. In this study, we set out to examine the relationship between adults of this species and meteorological factors, such as air temperature and humidity. The study lasted for two years (2019–2020) and was performed on three plots in Romania, in Ilfov, Giurgiu, and Călărași counties. In the first year, the seasonal dynamics of the OLB populations and the meteorological factors potentially influencing those were studied, whilst in the second year, the dynamics of the diurnal activity of the insect population were examined. We found that Corythucha arcuata experienced two population peaks—in July and August—and a diurnal population dynamic that reached a maximum at midday. Data analysis indicated that, for most of the time, the adult activity was influenced by both temperature and humidity. In addition, the population dynamics were not constant over the course of the day, preferring relatively high temperatures and low humidity but not exceeding certain thresholds of thermal discomfort.
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