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A small number of longhorn beetle species (Coleoptera: Chrysomeloidea: Cerambycidae) have the potential to become invasive forest pests. International trade in live plants and wood packaging material are known invasion pathways for longhorn beetles. Once an invasive pest is intercepted in a new region, a rapid pest risk analysis is often needed to determine the appropriate response. For accurate risk quantification, natural history evidence is necessary. This information is also vital in preventing introduction. This study gathered insect collection data, especially references to host plants, of xylophagous longhorn beetles from the Institute of Zoology, Chinese Academy of Sciences, Beijing, China. Beetle associations with three important host groups were investigated: Fagaceae, Citrus spp., and avocado (Persea americana). We performed a systematic literature review to identify previously documented cerambycidae associated with these plants. Here, we report insect-plant host associations for 39 species of longhorn beetles based on a review of the literature; 43 interactions were documented, 10 interactions were novel. No host associations were recorded with avocado in China. This information serves as a foundation for pest risk analysis in determining threats posed by potentially invasive longhorn beetles into new regions. [ABSTRACT FROM AUTHOR]

Abstract Background The Siberian moth (Dendrolimus sibiricus) is a serious pest of conifers in Russia, Northern Kazakhstan, Mongolia and China. The western border of the pest’s distribution in Russia is disputed, but it is present west of the 60th meridian east. The pest has the potential to defoliate a wide range of conifers. Results The pest is not present in Norway or other European countries, except Russia. Natural spread and human mediated transport are potential pathways for the pest. Human mediated pathways considered are: Living trees for planting, coniferous wood in the rough and foliage and branches. There has been no import of living trees from Russia to Norway during the past 30 years, and there is currently no import of coniferous wood commodities containing bark from areas, where D. sibiricus occurs. Conclusions The probability of D. sibiricus entry by natural spread is unlikely, mainly because of the geographical distance and the partial sea barriers between Norway and the infested areas. The probability of entry by human mediated pathways is unlikely due to the very limited volume of the import. Should the pest enter Norway, the probability of establishment and spread is unlikely, due to the suboptimal climatic conditions, and the fact that the two dominant conifers in the country, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), are intermediate and poor hosts, respectively. The potential damage, should D. sibiricus enter Norway, is considered low.

Aeolesthes sarta (Solsky 1871) (Coleoptera: Cerambycidae) is a polyphagous longhorned beetle species that primarily damages broadleaved tree species. This pest is distributed in the western and northern regions of Pakistan, where it caused serious damage to Populus spp. plantations. However, the growth and dispersal patterns of insects and pests are changing due to climate change. Modeling the range expansion or contraction of A. sarta development regions in Pakistan was the goal of the current study, assuming climate change might influence the geographical distribution of A. sarta in Pakistan. Under historical and future climatic conditions, A. sarta distribution areas were estimated using the CLIMEX model. Three time periods, 2030 (early century), 2070 (late century), and 2100 (end century), were forecasted for habitat suitability using the two climate change scenarios (CCSs) A1B and A2. Under the historic climatic condition (HCC), A. sarta was distributed in most areas of Pakistan, and its optimum habitat accounted for 71.67% of its total potential distribution. In the early-century period, optimum habitat dropped to 50.60% and 52.22% under A1B and A2 scenarios in the suitable condition. In the late-century period, optimum habitat further reduced to 31.76% and 30.60% under A1B and A2 scenarios. Moreover, at the end-century period, severe range shrinkage was predicted in the optimum habitat (19.99% under both CSSs). The model predicted a shift in the suitable habitat areas for A. sarta to the west and north. Furthermore, most climatically suitable areas under historic conditions became unsuitable during the end-century period. These projected results will assist in identifying the impacts of global warming on the possible distribution of A. sarta, thereby offering vital information for developing early forecasting and pest-prevention techniques to prevent further loss of forest and woodland trees.

Controlling forest pests to maintain the sustainability of forests and ecosystem balance is one of the interests of modern forestry. In the evaluation of damage risks associated with forest pests, pheromone traps attract attention by providing early warnings. With the development of these traps in line with modern technology, more reliable data are obtained; these data are important in the identification and planning of pest management. In this study, a pheromone trap with electronic control unit was tested under field conditions. The capture of adult Ips sexdentatus under natural conditions during 103 days of the flying period was evaluated; 97.2% of the beetles captured in the trap were the target species. The comparison of the number of beetles recorded by the trap and manual counts revealed that the trap worked with an error margin of approximately 4%. However, no statistically significant difference was noted between these two counting methods. During the study, 59% of the total beetles were captured between May 27 and June 25. The average temperature at the period of the capture was 20.09 °C, average humidity was 66%, and average wind speed was 2.9 m/s. Of the captures, 73.9% occurred in the temperature range of 15–24.9 °C, 61.1% occurred in humidity range of 61–90%, 89.6% occurred at a wind speed of 0.3–5.4 m/s, and 77.3% occurred within the period from sunrise to sunset. When these four parameters were evaluated together, the most strongly associated parameter was daylight, followed by temperature, wind speed, and humidity. [ABSTRACT FROM AUTHOR]

Dispersal flights by the mountain pine beetle have allowed range expansion and major damage to pine stands in western Canada. We asked what the genetic and transcriptional basis of mountain pine beetle dispersal capacity is. Using flight mills, RNA-seq and a targeted association study, we compared strong-flying, weak-flying, and non-flying female beetles from the recently colonized northern end of their range. Nearly 3,000 genes were differentially expressed between strong and weak flying beetles, while weak fliers and nonfliers did not significantly differ. The differentially expressed genes were mainly associated with lipid metabolism, muscle maintenance, oxidative stress response, detoxification, endocrine function, and flight behavior. Three variant loci, two in the coding region of genes, were significantly associated with flight capacity but these genes had no known functional link to flight. Several differentially expressed gene systems may be important for sustained flight, while other systems are downregulated during dispersal and likely to conserve energy before host colonization. The candidate genes and SNPs identified here will inform further studies and management of mountain pine beetle, as well as contribute to understanding the mechanisms of insect dispersal flights. [ABSTRACT FROM AUTHOR]

The Western conifer seed bug Leptoglossus occidentalis, a native insect of North America, was accidentally introduced in Europe in the late 1990s. Since then, it has spread rapidly. Biological control could provide an efficient management option but natural enemies of the pest have been poorly examined in Europe.In this study, we exposed sentinel egg masses and collected naturally laid egg masses in southern France in 2016 and 2017, to identify the egg parasitoids of L. occidentalis and investigate their potentials.Three egg parasitoids were detected: Anastatus bifasciatus, Ooencyrtus pityocampae and Ooencyrtus telenomicida. The overall parasitism was low compared to that observed in the native range with 6.4% of all eggs being parasitized, while 17.1% of egg masses carried at least one parasitized egg. The total number of parasitized egg masses was similar between parasitoid species, but the mean number of parasitized eggs per egg mass was highest for A. bifasciatus (5.57 vs. 1.25 for Ooencyrtus spp.).Sentinel egg masses underestimated the parasitism compared to natural egg masses (respectively, 1.42% and 7.71%).Our results suggested that the three generalist parasitoids detected can respond in a Leptoglossus egg density‐dependent manner, but this requires further investigations. [ABSTRACT FROM AUTHOR]

Khaya grandifoliola C. DC. (Meliaceae), known as African mahogany, is used in the establishment of commercial plantations for high-value timber production. This work aims to report the first occurrence of the genus Atta in a commercial plantation of this species. An ant nest mound with 105 m2 of loose soil and five active ant holes were observed. Leaves cut into crescent shaped sections and pieces of young branches were found near these holes, in addition to trees with the apical part of their crown partially defoliated. The collected specimens were identified as Atta laevigata Smith (Hymenoptera: Formicidae: Attini), locally known as the glass-head leaf-cutting ant.

Dispersal flights by the mountain pine beetle have allowed range expansion and major damage to pine stands in western Canada. We asked what the genetic and transcriptional basis of mountain pine beetle dispersal capacity is. Using flight mills, RNA-seq and a targeted association study, we compared strong-flying, weak-flying, and non-flying female beetles from the recently colonized northern end of their range. Nearly 3,000 genes were differentially expressed between strong and weak flying beetles, while weak fliers and nonfliers did not significantly differ. The differentially expressed genes were mainly associated with lipid metabolism, muscle maintenance, oxidative stress response, detoxification, endocrine function, and flight behavior. Three variant loci, two in the coding region of genes, were significantly associated with flight capacity but these genes had no known functional link to flight. Several differentially expressed gene systems may be important for sustained flight, while other systems are downregulated during dispersal and likely to conserve energy before host colonization. The candidate genes and SNPs identified here will inform further studies and management of mountain pine beetle, as well as contribute to understanding the mechanisms of insect dispersal flights.

An essential component of plant defense is the change that occurs from a constitutive to an induced state following damage or infection. Exogenous application of the plant hormone methyl jasmonate (MeJA) has shown great potential to be used as a defense inducer prior to pest exposure, and could be used as a plant protection measure. Here, we examined (1) the importance of MeJA-mediated induction for Norway spruce (Picea abies) resistance against damage by the pine weevil Hylobius abietis, which poses a threat to seedling survival, and infection by the spruce bark beetle-associated blue-stain fungus Endoconidiophora polonica, (2) genotypic variation in MeJA-induced defense (terpene chemistry), and (3) correlations among resistance to each pest. In a semi-field experiment, we exposed rooted-cuttings from nine different Norway spruce clones to insect damage and fungal infection separately. Plants were treated with 0, 25, or 50 mM MeJA, and planted in blocks where only pine weevils were released, or in a separate block in which plants were fungus-inoculated or not (control group). As measures of resistance, stem area debarked and fungal lesion lengths were assessed, and as a measure of defensive capacity, terpene chemistry was examined. We found that MeJA treatment increased resistance to H. abietis and E. polonica, but effects varied with clone. Norway spruce clones that exhibited high constitutive resistance did not show large changes in area debarked or lesion length when MeJA-treated, and vice versa. Moreover, insect damage negatively correlated with fungal infection. Clones receiving little pine weevil damage experienced larger lesion lengths, and vice versa, both in the constitutive and induced states. Changes in absolute terpene concentrations occurred with MeJA treatment (but not on proportional terpene concentrations), however, variation in chemistry was mostly explained by differences between clones. We conclude that MeJA can enhance protection against H. abietis and E. polonica, but the extent of protection will depend on the importance of constitutive and induced resistance for the Norway spruce clone in question. Trade-offs among resistances do not necessarily hinder the use of MeJA, as clones that are constitutively more resistant to either pest, should show greater MeJA-induced resistance against the other.

The sweetgum inscriber (SI) Acanthotomicus suncei Cognato is an emerging bark beetle pest that seriously damages American sweetgum trees (Liquidambar styraciflua) and Chinese sweetgum trees (L. formosana) in China. Since 2013, SI has killed more than 30,000 sweetgum trees in Shanghai and adjacent areas. In Shanghai, SI was observed to emerge from infested wood between April–September and exhibited two generations per year. Both the flying populations and those in colonized logs were female‐biased. After the parental adult initiates a gallery, the emergence of new adults required 73.4 ± 0.7 days at 30°C and 163.5 ± 0.9 days at 20°C. SI could not sustain population development at constant temperatures ≤15°C. The fungi Geosmithia spp. and Phaeoacremonium tuscanum were common associates of SI. The results suggest that SI has a long flight period, and its development is sensitive to low temperatures. Fungi associated with SI were not pathogenic to American sweetgum trees, but their presence may indirectly increase the probability of tree mortality. Our findings contribute to the prevention and control of this important emerging bark beetle pest. [ABSTRACT FROM AUTHOR]

Winter moth, Operophtera brumata, native to Europe, invaded the northeastern United States in the late 1990s, where it caused widespread defoliation of forests and shade trees ranging from 2,266 to 36,360 ha/yr between 2003 and 2015 in Massachusetts. In 2005, we initiated a biological control effort based on the specialist tachinid parasitoid Cyzenis albicans, which had previously been introduced along with the generalist ichneumonid parasitoid Agrypon flaveolatum to control winter moth in Nova Scotia in the 1950s and British Columbia in the 1970s. Due to concerns of possible non‐target impacts by A. flaveolatum, we focused entirely on the specialist C. albicans. Each year for 14 yr, we collected several thousand individuals of C. albicans from British Columbia and released them in widely spaced sites in the northeastern United States. As of 2020, we had established C. albicans at 41 of 44 sites from coastal Maine to southeastern Connecticut. By 2016, winter moth densities (pupae/m2) had declined from 100–500 to 0–10 pupae/m2 at six release sites at least 10 km apart and this was coincident with the onset of 10–40% parasitism. At one site in Wellesley, Massachusetts, the decline occurred in 2012 and winter moth densities have remained low for seven subsequent years. Defoliation in Massachusetts has been reduced to undetectable levels by aerial survey since 2016. DNA sequencing of the barcoding region of the mitochondrial gene CO1 confirmed that all C. albicans reared from winter moth matched the C. albicans collected from Vancouver Island and were distinct from parasitic flies (presumably a native species) reared from a native congener of winter moth, Bruce spanworm (O. bruceata). Successful establishment of C. albicans on winter moth represents a rare, if not the only, example of the biological control of a major forest defoliator that attacks a wide range of tree species anywhere in the world by the establishment of a single specialist natural enemy. [ABSTRACT FROM AUTHOR]

An essential component of plant defense is the change that occurs from a constitutive to an induced state following damage or infection. Exogenous application of the plant hormone methyl jasmonate (MeJA) has shown great potential to be used as a defense inducer prior to pest exposure, and could be used as a plant protection measure. Here, we examined (1) the importance of MeJA-mediated induction for Norway spruce (Picea abies) resistance against damage by the pine weevil Hylobius abietis , which poses a threat to seedling survival, and infection by the spruce bark beetle-associated blue-stain fungus Endoconidiophora polonica , (2) genotypic variation in MeJA-induced defense (terpene chemistry), and (3) correlations among resistance to each pest. In a semi-field experiment, we exposed rooted-cuttings from nine different Norway spruce clones to insect damage and fungal infection separately. Plants were treated with 0, 25, or 50 mM MeJA, and planted in blocks where only pine weevils were released, or in a separate block in which plants were fungus-inoculated or not (control group). As measures of resistance, stem area debarked and fungal lesion lengths were assessed, and as a measure of defensive capacity, terpene chemistry was examined. We found that MeJA treatment increased resistance to H. abietis and E. polonica , but effects varied with clone. Norway spruce clones that exhibited high constitutive resistance did not show large changes in area debarked or lesion length when MeJA-treated, and vice versa. Moreover, insect damage negatively correlated with fungal infection. Clones receiving little pine weevil damage experienced larger lesion lengths, and vice versa, both in the constitutive and induced states. Changes in absolute terpene concentrations occurred with MeJA treatment (but not on proportional terpene concentrations), however, variation in chemistry was mostly explained by differences between clones. We conclude that MeJA can enhance protection against H. abietis and E. polonica , but the extent of protection will depend on the importance of constitutive and induced resistance for the Norway spruce clone in question. Trade-offs among resistances do not necessarily hinder the use of MeJA, as clones that are constitutively more resistant to either pest, should show greater MeJA-induced resistance against the other. [ABSTRACT FROM AUTHOR]

Understanding variation in tree regeneration among species and sites, and how well forest size class distribution (seedlings, saplings, and trees) portends long-term species compositional change, may assist managing forests during contemporary global change rapidly altering forests, such as after invasion by introduced pests. In northwestern Ohio, one of the North American regions longest invaded by emerald ash borer (EAB, Agrilus planipennis), we 1) examined variation in size class abundance among tree species and sites in 22 forested wetlands in 2018 and 2021; and 2) assessed how closely size class distribution of tree species in 2005, at the onset of EAB invasion before Fraxinus trees died, forecasted observed forest change during the next 17 years. In 2018 and 2021, three major groups of tree species emerged with respect to their frequency across size classes: 1) species commonly in all three, or at least two, size classes on a site, 2) species frequent in only one size class, which varied but was often seedlings, and 3) species almost always present only as trees, with little advance regeneration. Shade tolerance correlated with species occurring in all three size classes. Among sites in 2018 and 2021, abundance of regeneration and similarity of species composition across size classes varied between years (largely from fluctuations in seedlings) and with site factors. Sites with the least regeneration had high soil available water capacity and high cover of graminoids. On long-term sites after the onset of EAB invasion in 2005, all seedling-to-sapling and sapling-to-tree advancements recorded through 2021 were from species already present in 2005, and only shade-tolerant species (e.g., Ulmus americana) advanced. Results suggest that there is substantial variation in advance regeneration availability among species and sites in forested wetlands across the EAB-invaded landscape. Portions of this variability were structured into well-demarcated groups of similarly responding species and sites, were associated with species traits such as shade tolerance and site factors such as soil texture, and were prognostic of forest changes within the first two decades after EAB invasion. • Tree species grouped according to their distribution across size classes. • Occurrence as only seedlings or trees was more common than in all sizes. • Shade-tolerant species most commonly occurred across all size classes. • High soil water capacity and graminoids correlated with minimal tree regeneration. • All tree recruitment through 2021 originated from species already present in 2005. [ABSTRACT FROM AUTHOR]

Hemlock wooly adelgid (HWA), Adelgests ugae Annand (Hemiptera: Adelgidae), is a species native to Asia but later ravages Endangered hemlock forests (Tsuga spp.) in eastern North America. In this study, we obtained the first complete mitochondrial genome of HWA (16,509 bp in length) using meta-genomic sequencing method. The HWA mitogenome has a general gene annotation as other aphids, comprising 13 protein-coding genes, 22 transfer RNAs, and 2 ribosomal RNAs. Our phylogenetic result showed Aphidoidea is sister to Coccoidea and the newly sequenced mitogenome is put on the correct position, sister to Adelgeslaricis.

Emerald ash borer Agrilus planipennis (Coleoptera: Buprestidae) is a quarantine pest posing a threat to ash trees all over Europe. This wood-boring beetle native to Asia is quickly spreading in North America and European Russia, and approaching the European Union and the Middle East. It is important to study microorganisms associated with this pest, because the knowledge of its “natural enemies” and “natural allies” could be potentially used for the control of the pest. All previously published information about the A. planipennis microbiome was obtained in North America and China. We present the first study on procaryotes associated with A. planipennis in Europe. Alive larvae were sampled from under the bark of Fraxinus pennsylvanica in the Moscow Oblast and the gut microbiome was studied using metagenomic methods. Next-generation Illumina-based amplicon sequencing of the v3-v4 region 16S-RNA gene was performed. In total, 439 operational taxonomic units from 39 families and five phyla were detected. The dominant families in our samples were Pseudomonadaceae, Erwiniaceae and Enterobacteriaceae, in accordance with the published information on the larval gut microbiome in North America and China. We detected intracellular bacteria in A. planipennis for the first time, namely Rickettsia (Rickettsiaceae) and Rickettsiella (Diplorickettsiaceae). Representatives of the genus Rickettsia are known to be in mutualistic symbiosis with some phytophagous insects, while Rickettsiella bacteria are pathogenic to many arthropods. The finding of Rickettsia and Rickettsiella opens perspectives for future research on the interactions between these bacteria and A. planipennis and the possible use of these interactions for the control of the pest.

Here we report new records of two invasive ambrosia beetles, Xyleborus affinis and X. ferrugineus, in mainland China. For X. affinis, 89 specimens were collected at 12 locations from five hosts (Eucalyptus robusta, Eucalyptus sp., Hevea brasiliensis, Schefflera octophylla and Sindora glabra) during 2014-2019. In 2019, there are only two samples of X. ferrugineus found in a dead log in Guangdong province. We suspected that both were likely introduced to China through international trade, and X. affinis may have arrived by natural dispersal. More investigation and research are needed to determine distribution, biology and ecology of these two Xyleborus species in China. [ABSTRACT FROM AUTHOR]

BACKGROUND: The pine weevil (Hylobius abietis) is a major forest regeneration pest causing high levels of seedling mortality and economic losses. Current management relies on silviculture, stem coatings and insecticides. Here we evaluated for the first time the effects of Bacillus thuringiensis (Bt) strains on H. abietis adults: two producing the Coleoptera‐targeted toxins Cry3Aa (Bt tenebrionis NB‐176) and Cry8Da (Bt galleriae SDS‐502), and one producing the Diptera‐targeted Cry10A (Bt israelensis AM65‐52). Choice and nonchoice assays using individual and mixtures of Bt formulations, containing these strains respectively, were conducted. RESULTS: We found that Bt had toxic and lethal effects on H. abietis, but effects varied with strain and formulation concentration. The Diptera‐targeted Bt israelensis had the most negative effects on weevil weight, feeding and mortality (70–82% feeding reduction, 65–82% greater mortality than control), whereas the effect was lower for the Coleoptera‐specific Bt tenebrionis (38–42%; 37–42%) and Bt galleriae (11–30%; 15–32%). Reduced weevil feeding was observed after 3 days, and the highest mortality occurred 7–14 days following Bt exposure. However, we found no synergistic toxic effects, and no formulation combination was better than Bt israelensis alone at reducing consumption and survival. Also, pine weevils were not deterred by Bt, feeding equally on Bt‐treated and non‐Bt treated food. CONCLUSION: There is potential to develop forest pest management measures against H. abietis that include Bt, but only the Diptera‐targeted Bt israelensis would provide effective seedling protection. Its Diptera‐specificity may need reconsideration, and evaluation of other Bt strains/toxins against H. abietis would be of interest. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Aim: Invasive species are ideal systems for testing geographical differences in performance traits and measuring evolutionary responses as a species spreads across divergent climates and habitats. The European gypsy moth, Lymantria dispar dispar L. (Lepidoptera: Erebidae), is a generalist forest defoliator introduced to Medford, Massachusetts, USA in 1869. The invasion front extends from Minnesota to North Carolina and the ability of this species to adapt to local climate may contribute to its continuing spread. We evaluated the performance of populations along the climatic gradient of the invasion front to test for a relationship between climate and ecologically important performance traits. Location: Eastern United States of America Taxon: Lymantria dispar dispar L. (Lepidoptera: Erebidae) Methods: Insects from 14 populations across the US invasion front and interior of the invasive range were reared from hatch to adult emergence in six constant temperature treatments. The responses of survival, pupal mass and larval development time were analysed as a function of source climate (annual mean normal temperature), rearing temperature and their interaction using multiple polynomial regression. Results: With the exception of female development time, there were no significant interactions between source climate and rearing temperature, indicating little divergence in the shape of thermal reaction norms among populations. Source population and rearing temperature were significant predictors of survival and pupal mass. Independent of rearing temperature, populations from warmer climates had lower survival than those from colder climates, but attained larger body size despite similar development times. Larval development time was dependent on rearing temperature, but there were not consistent relationships with source climate. Main Conclusions: Thermal adaptation can be an important factor shaping the spread of invasive species, particularly in the context of climate change. Our results suggest that L. d. dispar is highly plastic, but has undergone climate‐related adaptation in thermal performance and life‐history traits as it spread across North America. [ABSTRACT FROM AUTHOR]

Ips duplicatus (Coleoptera: Curculionidae) is a bark beetle that recently invaded southern Europe. It produces intense outbreaks in the spruce stands installed outside their natural area. Pheromone dispensers with different designs are used for monitoring this species. Compounds are released either by wick (ID Ecolure) or polyethene foil (ID RO and Pheagr IDU). We performed a series of laboratory and field experiments to compare the efficiency and sustainability of these dispensers in terms of pheromone release. The first experiment compared the Ips duplicatus capture dynamics between the ID Ecolure and ID RO in pheromones traps in three localities for 60 days. Release rates of used dispensers were evaluated in the same period. The second experiment analyzed headspace chemical composition in three dispensers (ID Ecolure, ID RO, Pheagr IDU) and tested their activity in pheromone traps. Active compounds content released by tested dispensers varied. The wick dispensers’ release rates (ID Ecolure) were strongly reduced from 365 to 50 mg/day within two weeks and then steadily to 16 mg/day after 60 days. Release rates of the polyethene dispensers (ID RO) remained constant over 60 days (20–24 mg/day). The highest initial emission was in the ID Ecolure. The ratio of pheromone components (ipsdienol/E-myrcenol) was lower for ID Ecolure (5) and ID RO (10) and higher for Pheagr IDU (565). In the field experiments, significantly more Ips duplicatus were caught with ID Ecolure than ID RO and Pheagr IDU in the first two weeks. Later, the attractivity of ID RO remained high, but captures by ID Ecolure were significantly reduced. The captures of Ips typograhus were also considered. We propose that the wick-type dispensers are a promising tool for controlling the hibernating beetle generation. The foil release dispensers can be used to monitor Ips duplicatus flight activity.

The mistletoe Phoradendron velutinum (P. velutinum) is a pest that spreads rapidly and uncontrollably in Mexican forests, becoming a serious problem since it is a cause of the decline of 23.3 million hectares of conifers and broadleaves in the country. The lack of adequate phytosanitary control has negative social, economic, and environmental impacts. However, pest management is a challenging task due to the difficulty of early detection for proper control of mistletoe infestations. Automating the detection of this pest is important due to its rapid spread and the high costs of field identification tasks. This paper presents a Genetic Programming (GP) approach for the automatic design of an algorithm to detect mistletoe using multispectral aerial images. Our study area is located in a conservation area of Mexico City, in the San Bartolo Ameyalco community. Images of 148 hectares were acquired by means of an Unmanned Aerial Vehicle (UAV) carrying a sensor sensitive to the R, G, B, red edge, and near-infrared bands, and with an average spatial resolution of less than 10 cm per pixel. As a result, it was possible to obtain an algorithm capable of classifying mistletoe P. velutinum at its flowering stage for the specific case of the study area in conservation area with an Overall Accuracy (OA) of 96% and a value of fitness function based on weighted Cohen’s Kappa (kw) equal to 0.45 in the test data set. Additionally, our method’s performance was compared with two traditional image classification methods; in the first, a classical spectral index, named Intensive Pigment Index of Structure 2 (SIPI2), was considered for the detection of P. velutinum. The second method considers the well-known Support Vector Machine classification algorithm (SVM). We also compare the accuracy of the best GP individual with two additional indices obtained during the solution analysis. According to our experimental results, our GP-based algorithm outperforms the results obtained by the aforementioned methods for the identification of P. velutinum.

Winter moth, Operophtera brumata L. (Lepidoptera: Geometridae), causes widespread defoliation in both its native and introduced distributions. Invasive populations of winter moth are currently established in the United States and Canada, and pheromone-baited traps have been widely used to track its spread. Unfortunately, a native species, the Bruce spanworm, O. bruceata (Hulst), and O. bruceata × brumata hybrids respond to the same pheromone, complicating efforts to detect novel winter moth populations. Previously, differences in measurements of a part of the male genitalia called the uncus have been utilized to differentiate the species; however, the accuracy of these measurements has not been quantified using independent data. To establish morphological cutoffs and estimate the accuracy of uncus-based identifications, we compared morphological measurements and molecular identifications based on microsatellite genotyping. We find that there are significant differences in some uncus measurements, and that in general, uncus measurements have low type I error rates (i.e. the probability of having false positives for the presence of winter moth). However, uncus measurements had high type II error rates (i.e. the probability of having false negatives for the presence of winter moth). Our results show that uncus measurements can be useful for performing preliminary identifications to monitor the spread of winter moth, though for accurate monitoring, molecular methods are still required. As such, efforts to study the spread of winter moth into interior portions of North America should utilize a combination of pheromone trapping and uncus measurements, while maintaining vouchers for molecular identification. [ABSTRACT FROM AUTHOR]

Since 2008, spruce bud blight (Gemmamyces piceae (Borthw.) Casagr.) has been spreading epidemically in forest stands of the Czech Republic’s Ore Mountains. This fungus, with a disjunct Holarctic range, injures buds, especially of Colorado blue spruce (Picea pungens Engelm.). Damaged buds do not sprout, and, in case of a stronger attack, the tree does not recover its assimilation apparatus and may die. Within the past few years, there has been a huge spread of this fungus throughout the mountain range. This paper summarizes the biology of G. piceae, its host plants, and presents the first findings from the massive outbreak of G. piceae. In 2015, an increase in damage was detected on Norway spruce (Picea abies (L.) Karst). The course of the G. piceae epidemic had been monitored in 25 permanent research plots over the course of 11 years. In the case of Colorado blue spruce, stands aged 10–60 years were attacked, with 60% of buds damaged on average. The intensity of damage to Norway spruce buds was around 25%. Norway spruce infestation varied significantly depending upon the age of the stand (GLMM: p < 0.01). In the age class of 31–60 years, on average 80% of individuals were infested. In older stands, only 42% of trees were infested, and no infestation was found in individuals younger than 15 years. In Colorado blue spruce, the distribution of the pathogen was continuous, whereby all individuals in the research plots were affected, and, with the exception of a few trees, the infestation was lethal or resulted in a significant reduction of the assimilation apparatus. The development of damage on Colorado blue spruce can be characterized as continuous growth.

Abstract. This study aimed to evaluate qualitatively and quantitatively the Hypsipyla grandella (Zeller) damage in fruits of mahogany in Brasilia, Brazil. For this, fruits were collected and the analysis of each fruit was carried out by assessing the following parameters: fruit weight, fruit length and height, number of holes in fruits characteristic of H. grandella attack, size of the holes, number of larvae and pupae of H. grandella, number of seeds damaged and presence of other insects within the fruit. As a result, 190 (95%) had holes made by the larvae, used primarily for their entry and for exit later as an adult. Most of the fruits showed only a single hole (81%), but up to 5 holes were found in a single fruit. A single caterpillar can feed on various seeds, causing major damage when they attack together. Seventy-two (36%) fruits had all the seeds damaged by H. grandella, especially those containing pupae. 183 larvae in different instars and 45 pupae were found. Only five caterpillars were found dead inside of fruit, representing 2.78% of the caterpillars. Danos em frutos de mogno causados pela Hypsipyla grandella (Zeller) (Lepidoptera: Pyralidae) em Brasília, Brasil Resumo. Este trabalho teve como objetivo avaliar qualitativamente e quantitativamente os danos provocados por Hypsipyla grandella (Zeller) em frutos de mogno em Brasília, Brasil. Para isso, frutos foram coletados e os seguintes parâmetros foram analisados: peso, comprimento, número de orifícios causados pela H. grandella, número de sementes danificadas e presença de outros insetos no interior dos frutos. Como resultado, 190 (95%) frutos apresentaram orifícios feitos pela lagarta, usados primordialmente para sua entrada e posteriormente para a saída, quando adulto. A maioria dos frutos apresentou apenas um orifício (81%), mas até cinco furos foram encontrados em um único fruto. Uma única lagarta pode se alimentar de várias sementes, causando grandes danos. Setenta e dois frutos (36%) tinham todas as sementes danificadas por H. grandella, especialmente aqueles que apresentaram pupas. 183 lagartas em diferentes estádios e 45 pupas foram encontradas. Apenas cinco lagartas foram encontradas mortas dentro dos frutos, representando 2,78% do total.

The use of Bacillus thuringiensis (Bt) to control insect pests has already been established in various agronomic and forest crops. It is a bacterium that does not pollute the environment, is safe for mammals and vertebrates, lacks toxicity to plants and specifically targets insects. To date in-depth studies have not been conducted about the use of Bt to control the main pest of mahogany (Swietenia macrophylla King) and other Meliaceae species, the Hypsipyla grandella Zeller (Lepidoptera: Pyralidae). Therefore, this study aimed to test the pathogenicity of Bt strains on H. grandella caterpillars, as well to determine the lethal concentration required to kill 50% of the population (LC50) of the most promising strains. Ten strains of Bt toxic to lepidopteran proven in previous trials were used and these were incorporated into a natural diet with mahogany seeds to check their mortality. The LC50 of the top five strains was determined. The results indicate that H. grandella is highly susceptible to Bt toxins and the S1905 strain is highly toxic. Therefore, the use of Bt strains may be a tool to be incorporated into the integrated management of this important pest.

Pine wilt disease (PWD) caused by the pine wood nematode (PWN, Bursaphelenchus xylophilus) can, in suitable conditions, lead to mass mortality of susceptible trees. In the European Union, PWN is a quarantine pest. To support PWN risk management in Finland, we assessed the suitability of the Finnish present and future climate for both PWD and PWN establishment inside susceptible healthy trees. The former was done using the mean summer temperature concept and the latter by relating annual growing degree days to the likelihoods of PWN extinction and establishment inside healthy trees. The likelihoods were derived from the previously published modelling of PWN population dynamics for 139 locations in Germany. Both assessments were conducted using 10 × 10 km resolution climate data from 2000–2019 and Finland-specific climate change projections for 2030–2080. The results indicate that the present Finnish climate is too cool for both PWD and PWN establishment inside healthy trees. Furthermore, even global warming does not appear to turn the Finnish climate suitable for PWD or PWN establishment inside healthy trees by 2080, except under the worst-case representative concentration pathway scenario (RCP8.5). Consequently, giving top priority to PWN when allocating resources for biosecurity activities in Finland might deserve reconsideration.

Background: The Siberian moth (Dendrolimus sibiricus) is a serious pest of conifers in Russia, Northern Kazakhstan, Mongolia and China. The western border of the pest's distribution in Russia is disputed, but it is present west of the 60th meridian east. The pest has the potential to defoliate a wide range of conifers. Results: The pest is not present in Norway or other European countries, except Russia. Natural spread and human mediated transport are potential pathways for the pest. Human mediated pathways considered are: Living trees for planting, coniferous wood in the rough and foliage and branches. There has been no import of living trees from Russia to Norway during the past 30 years, and there is currently no import of coniferous wood commodities containing bark from areas, where D. sibiricus occurs. Conclusions: The probability of D. sibiricus entry by natural spread is unlikely, mainly because of the geographical distance and the partial sea barriers between Norway and the infested areas. The probability of entry by human mediated pathways is unlikely due to the very limited volume of the import. Should the pest enter Norway, the probability of establishment and spread is unlikely, due to the suboptimal climatic conditions, and the fact that the two dominant conifers in the country, Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), are intermediate and poor hosts, respectively. The potential damage, should D. sibiricus enter Norway, is considered low. [ABSTRACT FROM AUTHOR]

The common black field cricket, Gryllus assimilis (Orthoptera: Gryllidae), damages young plants of red cedar, Juniperus virginiana (Cupressaceae); strawberry, Fragaria × ananassa (Rosaceae); sugarcane, Saccharum officinarum (Poaceae); teak, Tectona grandis (Lamiaceae); upland cotton, Gossypium hirsutum (Malvaceae); and, mainly, Eucalyptus spp. (Myrtaceae). The objective of this study was to investigate the biological and behavioral parameters of this insect in the laboratory and in Eucalyptus spp. plantations in Inhambupe, Bahia State, Brazil. The incubation period and the viability of G. assimilis eggs were 11.87 days and approximately 22%, respectively. The duration of the nymphal stage was 62.34 days with approximately 60% of the nymphs obtained in the laboratory being females. The average number of egg batches per female, eggs per female, and eggs per batch per female of this insect were 25.50, 862.17, and 34.65, respectively. G. assimilis females lived for 76.50 days in the adult stage, and 138.34 days in total, from egg through nymph to adult. Males produced three characteristic sounds: one for the marking of territory, one for courtship, and one when alone. G. assimilis fed primarily on weeds but, in their absence, it damaged young Eucalyptus spp. plants. This paper presents important data on the biology and behavior of G. assimilis; this information may encourage additional biological research, laboratory rearing, and integrated management of this pest. [ABSTRACT FROM AUTHOR]

The European spruce bark beetle Ips typographus is the most important insect pest in Central European forests. Under climate change, its phenology is presumed to be changing and mass infestations becoming more likely. While several studies have investigated climate effects across a latitudinal gradient, it remains an open question how phenology will change depending on elevation and topology. Knowing how an altered climate is likely to affect bark beetle populations, particularly across diverse topographies and elevations, is essential for adaptive management. We developed a time‐varying distributed delay model to predict the phenology of I. typographus. This approach has the particular advantage of capturing the variability within populations and thus representing its stage structure at any time. The model is applied for three regional climate change scenarios, A1B, A2 and RCP3PD, to the diverse topography of Switzerland, covering a large range of elevations, aspects and slopes. We found a strong negative relationship between voltinism and elevation. Under climate change, the model predicts an increasing number of generations over the whole elevational gradient, which will be more pronounced at low elevations. In contrast, the pre‐shift in spring swarming is expected to be greater at higher elevations. In comparison, the general trend of faster beetle development on steep southern slopes is only of minor importance. Overall, the maximum elevation allowing a complete yearly generation will move upwards. Generally, the predicted increase in number of generations, earlier spring swarming, more aggregated swarming, together with a projected increase in drought and storm events, will result in a higher risk of mass infestations. This will increase the pressure on spruce stands particularly in the lowlands and require intensified management efforts. It calls for adapted long‐term silvicultural strategies to mitigate the loss of ecosystem services such as timber production protection against rockfall and avalanches and carbon storage. [ABSTRACT FROM AUTHOR]

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), quickly established itself as an invasive species in North America after it was first detected near Detroit, Michigan, USA, in 2002. Just 1 yr later, emerald ash borer was introduced accidentally into Maryland, USA, on imported ash nursery stock. After quarantine and eradication efforts failed, a classical biological control program was initiated in Maryland in 2009 with the release of 2 larval parasitoids: Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) and Spathius agrili Yang (Hymenoptera: Braconidae), and 1 egg parasitoid, Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae). Timing is critical to the success, efficiency, and cost-effectiveness of classical biological control programs where release of parasitoids must coincide temporally with that of susceptible stages of the host. In 2017, periodic field surveys at 2 sites in central Maryland were conducted to assess emerald ash borer phenology using green funnel traps to sample adults, and debarking infested ash trees to sample larval stages. Adult emerald ash borer first appeared in traps on 18 May 2017 (479 growing degree d base 10 [GDD10]), peaked on 15 Jun (823 GDD10), and were absent from 13 Jul (1,301 GDD10) through 12 Oct (2,598 GDD10) when surveys were terminated. Larval sampling in early Aug (1,698 GDD10) found all larval instars present, the most common being the second instar (46%), followed by the third instar (28%), fourth instar (20%), first instar (5%), and prepupal J-shaped larvae (J-larva) (0.5%). J-larvae are so called because after excavating a pupal chamber, the head is bent down 180 degrees to the rest of the body, resembling the shape of the letter J. Larval sampling in late Oct (2,710 GDD10) found J-larvae to be the dominant stage present (92.2%), followed by fourth instar (4.8%), third instar (2.4%), and second instar (0.6%). We found that emerald ash borer was univoltine, and that nearly 50% of emerald ash borer larvae had developed to stages susceptible to parasitism (third and fourth instar) by early Aug (1,698 GDD10). By late Oct (2,710 GDD10), 92% had developed beyond parasitoid susceptible stages (J-larvae). These findings suggest that egg parasitoid releases are best targeted from early May to late Jun at an approximate GDD10 range of 300 and 1,100 with larval parasitoid releases best targeted between 1,400 and 2,500 GDD10. [ABSTRACT FROM AUTHOR]

Bark beetles (Coleoptera: Curculionidae: Scolytinae) are a speciose subfamily of weevils that primarily live in bark and consequently largely communicate using sound. Having colonized multiple countries outside its native range, Hylurgus ligniperda (Fabricius) is considered to be a successful invader, yet little is known about its acoustic communication. In the present study, we investigate individual sound production and dyadic interactions among males and females of H. ligniperda. Two temporal parameters (duration and inter‐note interval) and three spectral parameters (minimum, maximum and centroid frequencies) are used as descriptors to quantify call variations depending on behavioural context. We also present a method for automatically extracting and analyzing these calls, which allows acoustic discrimination amongst individuals. Hylurgus ligniperda exhibits sexual dimorphism in its stridulatory organ. Females do not produce stridulatory sounds, whereas males produce single‐noted calls and modify their spectro‐temporal parameters in accordance with context. Acoustic stimulation from nearby males does not appear to be a causative factor in such modification. Instead, hierarchical clustering analysis shows that physical interactions play a more important role in affecting call parameters than acoustic signals. Centroid and maximum frequencies are the largest contributors to the variability of the data, suggesting that call variations in H. ligniperda mainly occur in the spectral domain. [ABSTRACT FROM AUTHOR]

Development of the double‐spined spruce bark beetle Ips duplicatus (Sahlberg, 1836) was investigated using the sandwich method under long‐day conditions (LD 18 : 6 h) at 10 constant temperatures: 7, 10, 12, 15, 20, 25, 30, 33, 35 and 39 °C. The method proved unsuitable at lower temperatures (7–12 °C), where high mortality occurred.At higher temperatures, development from egg to eclosion of adults shortened from 39.0 days at 15 °C to 10.3 days at 30 °C. Temperatures over 33 °C were lethal to all eggs, larvae and pupae. The developmental rate increased linearly at temperatures between 15 and 25 °C.Stage‐specific parameters, such as upper and lower developmental thresholds and optimum temperature for development, were determined by linear and nonlinear (Logan‐Lactin) models. Lower developmental thresholds obtained from nonlinear regression were calculated to be 9 °C (eggs), 6.1 °C (larvae), 6.9 °C (pupae) and 6.3 °C (development from eggs to pupae). Upper developmental thresholds for all stages oscillated around 39 °C and optimal temperatures oscillated around 30 °C.The rapid development of I. duplicatus at 15 and 30 °C [10 and 4 days faster than Ips typographus (L.), respectively] may explain its recent outbreak dynamics and low effectivity of preventive control measures [ABSTRACT FROM AUTHOR]

The invasive chestnut gall wasp (CGW), Dryocosmus kuriphilus, the worst pest of chestnut cultivation, has spread worryingly throughout Europe in less than 20 years. Despite the great concern around this pest, little is known about the status in its southernmost distribution in continental Europe. We assessed spatio-temporal patterns in the population dynamics, phenology and tree damage caused by CGW in southern Spain. Likewise, the relationship between these variables and thermal trends was evaluated. We found strong variation in the population dynamics and flight phenology among localities and over time, which were highly influenced by changes in thermal regimes. Specifically, warmer localities and vegetative periods promoted higher population densities, a partial increase in the survival of immature stages, and advanced flight activity. Moreover, tree damage evolved differently over time in each locality, which suggests that local conditions may determine differences in damage evolution. Our findings evidence that great spatio-temporal variability in the CGW populations takes place across invaded areas in its southernmost European distributional range. Although control mechanisms have been introduced, implementation of further control and management measures are critical to cope with this main threat for the chestnut industry and to prevent its spread to nearing chestnut-producing areas.

The oak flea weevil, Rhynchaenusmaculosus Yang et Zhang 1991, is a newly emerging pest that severely damages oak (genus Quercus) in China. The first R. maculosus outbreak occurred in 2020 and caused spectacular damage to all oak forests in Jilin province, northeast China. The lack of key morphological characters complicates the identification of this native pest, especially in larva and pupa stages. This is problematic because quick and accurate species identification is crucial for early monitoring and intervention during outbreaks. Here, we provided the first detailed morphological description of R. maculosus at four life stages. Additionally, we used DNA barcodes from larva and pupa specimens collected from three remote locations for molecular identification. The average pairwise divergence of all sequences in this study was 0.51%, well below the 2% to 3% (K-2-parameter) threshold set for one species. All sample sequences matched the R. maculosus morphospecies (KX657706.1 and KX657707.1), with 99.23% to 100% (sequence identity, E value: 0.00) matching success. The tree based on barcodes placed the specimens into the Rhynchaenus group, and the phylogenetic relationship between 62 sequences (30 samples and 32 from GeneBank) had high congruence with the morphospecies taxa. The traditional DNA barcodes were successfully transformed into quick response codes with larger coding capacity for information storage. The results showed that DNA barcoding is reliable for R. maculosus identification. The integration of molecular and morphology-based methods contributes to accurate species identification of this newly emerging oak pest.

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A high potential risk of pine weevil damage exists in NW Spain. • The amount of slash and the time since clear-felling influenced pine weevil risk. • Weevil risk was also related to the abundance of mature conifer forest. • Low-intensity management and forest landscape is favoring low pine weevil risk. • If the pine forest sector intensifies, weevil risk could be worryingly aggravated. The pine weevil (Hylobius abietis) is one of the most devastating pests of regenerated coniferous forests in northern and central Europe. Although it is also present and potentially harmful in southern Europe, little attention has been paid to this pest in that region. With the aim of quantifying the potential risk of the pine weevil as a forest pest in southern Europe, we performed an intensive assessment of weevil abundance and damage in 21 Pinus pinaster and P. radiata plantations established in recent coniferous clear-cuts in Galicia (NW Spain), i.e. in the south-western part of the natural distribution of H. abietis. The effect of several silvicultural and landscape factors as modulators of weevil risk was analyzed. Abundance of adult pine weevils was highly variable across the sampling plots, with the number of trapped insects significantly correlated with mean air temperature during each trapping period. Damage rate was, however, fairly constant across the whole study period. No significant relationship between pine weevil abundance and damage was observed. Up to 85% of the planted seedlings were attacked and the mortality rates reached 45% in some plots. No weevil preferences were found between the two pine species. Pine weevil damage was positively related to the amount of slash (logging waste) on the ground and negatively related to the time since clear-felling occurred. Once these factors were accounted for, the abundance of mature coniferous forest in the vicinity (500–2000 m) of the clear-cut significantly and positively affected pine weevil damage. We conclude that a high risk of pine weevil damage does exist in NW Spain. Low-intensity forest management together with the scarcity and discontinuity of mature conifer forest in the region seem to be the reason why this forest pest is largely ignored by forest owners and forest-health services. If the forest sector intensifies in this area, care should be taken to protect pine plantations against this devastating pest. [ABSTRACT FROM AUTHOR]

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The article focuses on the study of European gypsy moth, Lymantria dispar L., which is an invasive insect in North America that feeds on over 300 species of trees and shrubs and occasionally causes extensive defoliation. Topics discussed include effect of food availability and the movement patterns, Monte Carlo simulation model, and harmonic radar.

This dataset provides information about infestation caused by the pine processionary moth (Thaumetopoea pityocampa ([Denis & Schiffermüller], 1775)) in pure or mixed pine woodlands and plantations in Andalusia. It represents a long-term series (1993-2015) containing 81,908 records that describe the occurrence and incidence of this species. Data were collected within a monitoring programme known as COPLAS, developed by the Regional Ministry of Environment and Territorial Planning of the Andalusian Regional Government within the frame of the Plan de Lucha Integrada contra la Procesionaria del Pino (Plan for Integrated Control Against the Pine Processionary Moth). In particular, this dataset includes 4,386 monitoring stands which, together with the campaign year, define the dataset events in Darwin Core Archive. Events are related with occurrence data which show if the species is present or absent. In turn, the event data have a measurement associated: degree of infestation. [ABSTRACT FROM AUTHOR]

Coptotermes formosanus, known in its native China as the 'House White Ant', was introduced to the southeast USA likely in the 1950s, where it is known as the Formosan subterranean termite. In the USA it is best known as a pest of buildings in urban areas, however C. formosanus also attacks live trees along streets and in urban parks, suggesting it may be able to invade forests in the USA. A survey of 113 forest patches around Charleston South Carolina and New Orleans Louisiana, where C. formosanus was first recorded, found that 37% and 52%, respectively, were infested. Resistograph measurement of internal hollows in tree trunks in forest patches infested with C. formosanus found infested sites contained more and larger hollows compared with non-infested sites. Compared with forest patches free of C. formosanus, infested patches had 32% more trees with hollows in Charleston, and 115% more in New Orleans. Similarly, compared with patches free of C. formosanus, hollows were 2–3 times larger in infested patches in Charleston, and 2–6 times larger in New Orleans. Quercus (oak) and Acer (maple) were the most damaged trees in Charleston, whereas Carya (bitternut hickory), Taxodium (bald cypress), Nyssa (blackgum) and Liquidamber (sweetgum) were the most damaged in New Orleans. As termite damaged trees are more likely to die, these differing damage levels between tree species suggests that C. formosanus may alter community structure in US forests. [ABSTRACT FROM AUTHOR]

Highlights • Sirex noctilio outbreaks are synchronized at a regional scale. • Occurrence of S. noctilio outbreaks are triggered by an abrupt increase in drought. • Tree mortality decrease due to negative density-dependence in S. noctilio populations. • The damage caused by the outbreaks is determined by stand management variables. Abstract Insect outbreaks are among the most important biotic disturbances in forest ecosystems and can exert immense economic and ecological impacts. Understanding the spatio-temporal patterns of eruptive insects can provide insights into the mechanisms driving their dynamics and help predict future responses under climate change. The aims of this study were to analyze the spatio-temporal patterns of outbreaks of the woodwasp Sirex noctilio –a major invasive pest of pines– in an invaded region of South America, to assess the relative importance of density-dependent and density-independent mechanisms on population dynamics, and to identify the primary factors that influence the magnitude of outbreaks. We used tree ring and insect sampling data of more than 1000 trees to reconstruct S. noctilio outbreaks in 29 pine stands across Patagonia-Argentina over a 16-year period. We found marked spatial synchrony in S. noctilio outbreaks at a regional scale. Rates of tree mortality from S. noctilio were influenced by both density-dependent and density-independent factors. The occurrence of S. noctilio outbreaks are triggered by an abrupt increase in drought, which likely increases the availability of susceptible host trees. The damage caused by the outbreaks is determined by stand level variables, closely related with tree stress. Rates of tree mortality decreased over time due to negative density-dependence in S. noctilio populations, likely due to the loss of suitable resources over time. Depicting mechanisms of large-scale tree mortality in ecosystems provides insights to the drivers of forest outbreaks and other factors such as responses to a changing climate. [ABSTRACT FROM AUTHOR]

Understanding pine weevil [Hylobius abietis (L.)] feeding preferences and their relations to chemical defenses of pines may lead to improved protection of conifer seedlings across Europe and Asia. Previous studies showed reduced weevil damage in methyl jasmonate (MeJA) treated seedlings and that weevil preference for Monterey pine (Pinus radiata Ait.) or Maritime pine (Pinus pinaster D. Don) depended on feeding conditions. The present study explored whether volatile terpenes in plant tissues of control and MeJA-treated seedlings of these two pine species could explain differences in weevil feeding and seedling growth. Volatile terpenes of hexane extracts of needles and phloem were separated and identified by gas chromatography-mass spectrometry (GC-MS). The results confirmed that MeJA application reduced pine weevil feeding in both pine species, but the increase in resistance was not explained by any general change in the concentration of mono- and sesquiterpenes after MeJA application. MeJA effects on volatile terpenes differed between the two pine species. Responses to MeJA application were more intense in Monterey pine, for which total mono- and sesquiterpenes were induced and growth rates affected, even at the lowest concentration of MeJA (5 mM). In Maritime pine, seedling growth was affected only at the highest MeJA concentration (25 mM), and no effect was observed on total volatile terpenes. Contrasting effects of MeJA on key monoterpenes were also observed. In needles, the content of (−)-β-pinene, a monoterpene with deterrent properties against the pine weevil, increased in MeJA-treated seedlings of Monterey pine, but not in Maritime pine. In the phloem of Maritime pine, the MeJA treatment reduced the concentration of the pine weevil attractant (+)-α-pinene, whereas it was increased in Monterey pine. Altogether, results indicated that weevil preferences between the two species could be altered if resistance of seedlings were previously induced with MeJA. The differential inducibility of key volatile terpenes between the two pine species may be part of the explanation as to why pine weevil preferences to the two pine species differ between field and lab conditions. [ABSTRACT FROM AUTHOR]

The citrus longhorned beetle (CLB), Anoplophora chinensis (Forster), is a wood-boring beetle native to eastern Asia, where it is a major pest of citrus. It is highly polyphagous and attacks many species of broad-leaved trees. Expanding international trade, especially of bonsais and nursery trees imported from eastern Asia, has led to introduction of CLB beyond its native range, especially in Europe where it is currently a serious threat to ornamentals, the tree nursery industry, and urban forests, and is a potential threat to natural forests and the citrus industry. We present the history of 38 years (1980-Dec 2017) of CLB interceptions and discoveries of infestations in Europe; eradication activities, which are based on the CLB management rules developed by the European Union; and the current status of CLB infestations in Europe. There have been 115 reports of detection of CLB in 11 countries since the first report in 1980 (59 interceptions and 56 infestations, of which 49 were found in Italy). CLB is reported as eradicated from nine of the 11 countries as of December 2017, but populations are still established in Italy and Croatia. [ABSTRACT FROM AUTHOR]