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Infestations of ambrosia beetles in the tribe Xyleborini (Coleoptera: Scolytinae) are associated with economic losses to horticultural trees due to branch die‐back and tree death. Ethanol is a key attractant used for monitoring flight activity.Trapping experiments were conducted in woodlots in Ohio, USA, and Veneto, Italy, to characterize the effect of ethanol release rate on captures of Anisandrus maiche, Xyleborinus saxesenii, Xylosandrus crassiusculus and Xylosandrus germanus. In Ohio (2019, 2020 and 2021) and Italy (2021), traps were baited with centrifuge tubes that were modified to achieve ethanol release rates of 0.1–13.2 g/day. In Ohio (2022), traps were baited with varying quantities of manufactured lures to achieve release rates of 0.02–1.4 g/day.There was no consistent relationship between ethanol release rate and trap captures for the modified centrifuge tubes. In nine of sixteen analyses, traps baited with the centrifuge tubes releasing ethanol at 1.1 g/day or higher collected more A. maiche, X. saxesenii, X. crassiusculus and X. germanus than traps baited with centrifuge tubes releasing 0.1 g/day. In contrast, the manufactured lures releasing 0.1–1.4 g/day attracted more A. maiche, X. saxesenii, X. crassiusculus and X. germanus than lures releasing 0.02–0.05 g/day.This comprehensive study provides important insights into monitoring tactics for ambrosia beetles along with implications for optimizing ethanol‐baited traps as part of a 'push‐pull' strategy whereby repellents are used to 'push' beetles away from vulnerable trees and attractants are used to 'pull' them into annihilative traps. [ABSTRACT FROM AUTHOR]

The polyphagous shot hole borer (PSHB) beetle, Euwallacea fornicatus (Eichhoff) (Coleoptera: Curculionidae, Scolytinae), and its phytopathogenic fungal symbiont (Fusarium euwallaceae Freeman et al.) threaten commercial and urban tree species worldwide. This pest–fungus complex has been newly discovered in the commercial deciduous fruit industry (Western Cape, South Africa), where its effect is still unknown. This study explored the impact of PSHB infestation on fruit quality and plant water‐use efficiency (WUE) – as indicated by carbon and nitrogen stable isotope ratios – of commercially cultivated Packham's Triumph pear trees within the first year of invasion, as well as changes in phenotypic plasticity (trait expression range). The impact of PSHB infestation is currently most evident in fruit quality traits, with a clear distinction between the control and most densely attacked tree categories. Fruit and leaf traits showed high variation and a significant change in phenotypic plasticity. Increased PSHB attack density was associated with smaller, duller‐toned, sweeter fruit at the time of harvest and data tended towards reduced plant WUE. Producers can expect significant variation in fruit quality and plant WUE even in hosts without branch dieback, visible plant stress or extensive beetle breeding, especially in orchards where infestations persist beyond the first year. These findings necessitate additional research to describe the long‐term impact, examine the threat to other deciduous fruit crops and cultivars and assess the need for adapted management or harvesting methods. [ABSTRACT FROM AUTHOR]

Litsea deccanensis Gamble, a vital wet-season blooming tree in the Lauraceae family, faces a dual threat from the Redbay ambrosia beetle (Xyleborus glabratus) and the Molytinae weevil (Alcidodes porrectirostris). This study, conducted in the Western Ghats, India, explores the impact of these pests on L. deccanensis, a commercially significant species used in agarbatti production. Stem bark exploitation, coupled with laurel wilt disease, contributes to the tree's declining population. These stem borers cause considerable damage to both seedlings and young saplings, and their influence extends to infestations in mature trees. The Molytinae weevils primarily target seeds, posing a significant challenge for the storage and production of planting stock. This dual pest threat jeopardizes the natural regeneration of L. deccanensis, contributing to population decline in the wild. Recognizing the urgent need for conservation, this study marks a crucial step in developing proactive strategies to manage L. deccanensis effectively within its natural habitat, safeguarding this commercially valuable species from further decline. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between genetic and morphological evidence in a species complex of haplodiploid, near-inbred ambrosia beetles, which are also vectors of an invasive tree pathogen: Xyleborus ferrugineus, Xyleborus bispinatus, and Xyleborus impressus. The unorthodox genetic system may blur species boundaries and challenges the applicability of standard species concepts. Haplo-diploid scolytine systematics is rife with contentious species delimitation, but species limits have rarely been tested empirically. To test the congruence of morphology, genetics, and geography in species identity, we analyzed 16 morphological characters and two DNA barcodes (COI mtDNA and CAD DNA sequences) in samples from across Florida. Morphological characters used to distinguish species corresponded with phylogenetic relationships in the majority of individuals. The maximum intraspecific divergence for the COI barcoding region was up to 19%, among the largest reported for animals. The phylogenetic and morphological analyses suggest that the three species are valid, but the astonishing intraspecific genetic diversity suggests either additional cryptic species or pseudogenes. [ABSTRACT FROM AUTHOR]

Euwallacea fornicatus is an invasive tree pest able to infest healthy plants and cause damage to many host plants. This beetle has become established in several countries where it was introduced. It has now become established in Brazil, and while the original introduction site remains uncertain, there is a possibility of multiple introductions. We report the first evidence for the establishment of E. fornicatus with molecular confirmation, as well as its distribution, and host plants in Brazil. Euwallacea fornicatus has spread to main commercial avocado groves, other monocultures, and native vegetation in the country, and its pest status puts it as a threat, mainly to Brazilian avocado producers. [ABSTRACT FROM AUTHOR]

Early detection of invasive species is critical for preventing ecological and economic damage and maintaining ecosystem health. In Hawaiʻi, a complex of generalist ambrosia beetle species in the tribe Xyleborini (Coleoptera: Scolytinae) are threatening the health and productivity of forests and crops due to their association with tree diseases such as rapid ʻōhiʻa death (ROD) and key agricultural commodities including coffee and macadamia.We conducted trapping experiments to determine the efficacy of semiochemicals to attract and repel Xyleborini ambrosia beetles within two ʻōhiʻa (Metrosideros polymorpha) forests on the Island of Hawaiʻi. We compared the attraction of beetles to 100% ethanol and a 1:1 mixture of ethanol: methanol at Waiākea Forest Reserve and ʻŌlaʻa Forest in Hawaiʻi Volcanoes National Park. In addition, we tested the extent to which verbenone and verbenone + methyl salicylate repellents (SPLAT® Verb and SPLAT® Beetle Guard, respectively) deterred beetles from baited traps at Waiākea Forest Reserve in two separate experiments.For all invasive ambrosia beetle species, including Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xyleborus perforans, Xylosandrus compactus, and Xylosandrus crassiusculus, more beetles were captured in traps baited with 100% ethanol than 1:1 ethanol: methanol. Across all species, both repellents were effective, with fewer beetles captured in traps equipped with repellents.Our research demonstrates the utility of semiochemicals for attracting and repelling invasive ambrosia beetle species in Hawaiʻi, and the potential use of these tools for early detection and management strategies. [ABSTRACT FROM AUTHOR]

The polyphagous shot hole borer beetle (PSHB, Euwallacea fornicatus) is a pest of global significance. PSHB is an ambrosia beetle which, together with its mutualistic fungi (including Fusarium euwallaceae), can cause the death of more than 100 tree species in invaded ranges. Management of PSHB mostly relies on the removal of infested plant material. Chemical control options have been investigated only in the USA and Israel and only on a few tree species. This study evaluated four chemical treatments for the therapeutic control of PSHB on American sweetgum (Liquidambar styraciflua) in South Africa (1) bifenthrin + surfactant (alcohol ethoxylate), (2) cypermethrin + surfactant (vitamin E) + salicylic acid, (3) emamectin benzoate, and (4) propiconazole. Trees were inoculated with F. euwallaceae and mature PSHB females using a novel technique to document fungal lesion development and PSHB colony establishment success. The bifenthrin and cypermethrin treatments reduced additional PSHB colonisation attempts on treated trees by ca. 40%, while the other treatments had no effect. Colony establishment success was reduced in all treatments by between 20 and 40%. Fungal growth was inhibited only after the application of propiconazole by ca. 36%. Gallery length and the number of PSHB individuals in successful colonies were unaffected by any of the chemical treatments. These results indicate that chemical control of PSHB is only partially effective. Successful PSHB management will likely depend on a combination of chemical control options and other control strategies in an integrated pest management program. [ABSTRACT FROM AUTHOR]

A molecular tool has been set up for the unambiguous molecular identification of the ambrosia beetle, Xyleborinus saxesenii (Ratzeburg, 1837) (Coleoptera Curculionidae Scolytinae), the cosmopolitan fruit‐tree pinhole borer, widely distributed in temperate regions of the five continents, where it infests a wide range of hardwoods and softwoods. The test was based on real‐time PCR with TaqMan probe technology and was developed on whole insect bodies (adults) as well as on frass produced by the beetle. The test was shown to meet the criteria established by EPPO for the harmonization of molecular diagnostic methods. In particular, the test gave good results in terms of analytical specificity (inclusivity and exclusivity) and analytical sensitivity, and was fully repeatable and reproducible. Since X. saxesenii is one of the most commonly intercepted ambrosia beetles during phytosanitary controls worldwide, this practical diagnostic tool will be useful for its rapid identification of the beetle in biological material (frass, body fragments). The test can be useful in countries where X. saxesenii is a quarantine species, as well as in the EPPO region. [ABSTRACT FROM AUTHOR]

A new species of ambrosia beetle Indocryphalus chiyui Lin & Beaver (tribe Xyloterini LeConte, 1876) from Taiwan is described. The species is monogamous and xylomycetophagous, breeding in Castanopsis cuspidata var. carlesii (Hemsl.) Yamazaki (Fagaceae). Indocryphalus sordidus (Blandford) is recorded for the first time from Taiwan. Diagnostic characters, biological data and a key to species of Indocryphalus in Taiwan are provided. [ABSTRACT FROM AUTHOR]

The Microperus ambrosia beetle fauna of Taiwan is reviewed. Microperus alpha (Beeson, 1929), M. kadoyamaensis (Murayama, 1934), M. kirishimanus (Murayama, 1955), M. perparvus (Sampson, 1922), M. quercicola (Eggers, 1926) have all been previously recorded from Taiwan. Microperus bucolicus Sittichaya, Smith & Beaver, 2021 and M. latesalebrinus Smith, Beaver & Cognato, 2020 are new country records for Taiwan. Of which, the males of M. alpha, M. bucolicus, M. kadoyamaensis, M. latesalebrinus, M. perparvus, and M. quercicola are described for the first time. In this study, we document a likely occurrence of mycocleptism by M. bucolicus. Diagnostic characters, biological data and a key to species in Taiwan are provided. [ABSTRACT FROM AUTHOR]

Black stem borer, Xylosandrus germanus (Coleoptera: Scolytinae), was first recorded in Croatia in 2009. Until now, the insect has been reported only as a part of ambrosia beetles entomofauna in oak stands (Quercus robur and Quercus petraea). In 2021, severe attack of ambrosia beetles causing tree decline and mortality have been observed in three orchards of hybrid sweet chestnut (Castanea sativa x Castenea crenata). Orchards near Topusko, Marija Bistrica and Vugrovec were inspected for the symptoms. Twenty-seven adult ambrosia beetle specimens were collected from eight samples of damaged sweet chestnut trees, and were identified according to their morphology. All 27 ambrosia beetles were morphologically identified as X. germanus. This is the first record of black stem borer causing damage on cultivated sweet chestnut in Croatia. Considering similar reports from Italy and Slovenia, X. germanus could be regarded as a new, potentially damaging pest in chestnut plantations.

Anisandrus maiche Stark (Coleoptera: Curculionidae: Scolytinae) is a non-native ambrosia beetle from central Asia that has been spreading throughout the eastern United States since 2005. Preferred hosts of A. maiche are not well characterized within its currently invaded range, but it is established in managed and natural forests throughout Indiana. Current monitoring and detection efforts for this beetle rely on ethanol-baited traps, but fungal volatiles may alter the attraction of A. maiche to ethanol. In this study, we conducted trapping experiments in Indiana to determine the extent to which a suite of common fungal alcohols influences the response of A. maiche to ethanol-baited traps. We then evaluated isoamyl and isobutyl alcohol as potential attractants for A. maiche and their ability to enhance attraction to ethanol. Lastly, we used SPME-GC-MS to identify volatiles from Ambrosiella cleistominuta (Mayers & Harr.), the fungal symbiont of A. maiche , grown for 7 and 14 days on malt extract agar. Benzyl alcohol, isobutyl alcohol, hexanol, methyl phenylacetate, phenethyl alcohol, and piperitone reduced the attraction of A. maiche to ethanol-baited traps in the field. Moreover, adding methyl benzoate and isoamyl alcohol individually to ethanol-baited traps did not further increase A. maiche capture. When paired with ethanol, isoamyl alcohol repelled beetles in the early flight period but did not significantly increase trap capture during the fall flight. These results represent a first step in understanding the role of fungal volatiles in the colonization behavior of A. maiche and may ultimately inform management strategies for this species. [ABSTRACT FROM AUTHOR]

Xylosandrus germanus (Blandford) is an invasive species of ambrosia beetle known to attack apple trees in North America. Xylosandrus germanus are attracted to ethanol produced by stressed and injured trees and can be a serious problem when grafting a new cultivar onto established fruit trees (topworking). The objective of this study was to evaluate the efficacy of 2 insecticides (emamectin benzoate and azadirachtin) and injection timing (fall and spring) on their ability to control X. germanus colonization in apple trees with simulated topworking. Our study shows evidence that both emamectin benzoate and azadirachtin injections can reduce X. germanus infestations; however, our results were inconsistent. The timing of injections influenced X. germanus, with spring injected azadirachtin being more effective than fall injections. Residue analyses of emamectin benzoate and azadirachtin showed the presence of residues in woody tissue comparable to those found in leaves. [ABSTRACT FROM AUTHOR]

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Simple Summary: The tea shot-hole borer (TSHB) is an invasive ambrosia beetle that vectors several fungal plant pathogens that cause Fusarium branch dieback in avocado trees. This study assessed the potential of four commercial products containing the entomopathogenic fungus Beauveria bassiana (Bb) for managing and mitigating the spread of the TSHB. The formulated fungal products tested were BioCeres WP, BotaniGard WP, BotaniGard ES and Velifer ES. Acquisition of spores by adult beetles dipped in the product suspensions with 2.5 ± 0.1 × 106 spores/mL was assessed. Survival time of beetles after residual exposure to the products in an in vivo avocado bark plug bioassay was also determined. Controls consisted of water only, BotaniGard ES and Velifer ES suspension supernatants with the spores removed. Production of Bb spores on beetles was assessed. Beetles exposed to Velifer ES and BotaniGard ES acquired significantly more spores than those exposed to the other fungal products. Beetles exposed to Velifer ES and BotaniGard ES died faster (6–8 days) compared to beetles treated with the other fungal products (10–11 days) and controls (12 days). Percentage mycosis was highest with beetles exposed to Velifer ES (63%). Spore production on cadavers of beetles dipped in Velifer ES was the highest among all treatments, whereas it was lowest on cadavers of beetles dipped in BotaniGard ES. All fungal products in this laboratory study demonstrated potential for use in management of the TSHB, especially Velifer ES. These Bb-based fungal products should be tested under field conditions to confirm these laboratory results. Euwallacea perbrevis, the tea shot-hole borer (TSHB), is an invasive ambrosia beetle that vectors several fungal pathogens that cause Fusarium branch dieback in avocado trees in southern Florida. This study assessed the potential of four commercial products containing the entomopathogenic fungus Beauveria bassiana (Bb) for managing adult TSHB beetles. Formulated products containing Bb strains to which adult beetles were exposed were BioCeres WP, BotaniGard WP, BotaniGard ES, and Velifer ES. Controls consisted of water only and BotaniGard ES and Velifer ES supernatant with spores removed. Acquisition of spores by adult beetles dipped in product suspensions with 2.5 ± 0.1 × 106 spores/mL was assessed. Survival time of beetles after residual exposure to the Bb-based products in an in vivo avocado bark plug bioassay was determined. Production of Bb spores on beetles after being dipped in product suspensions and placed in a moistened bark-plug assay with water only was assessed. Significantly more spores were acquired by beetles exposed to Velifer ES and BotaniGard ES than beetles exposed to the other fungal products. Beetles exposed to Velifer ES and BotaniGard ES died faster (6–8 days) compared to beetles dipped in the other fungal products (10–11 days) and controls (12 days). Percentage of mycosis was highest with beetles exposed to Velifer ES (63%). Spore production on cadavers of beetles dipped in Velifer ES (20 ± 6.4 × 105 spores/cadaver) was the highest among all treatments, whereas it was the lowest on cadavers of beetles dipped in BotaniGard ES (1 ± 0.2 × 105 spores/cadaver). All Bb-based products, especially Velifer ES, demonstrated potential to manage TSHB populations under laboratory conditions. These Bb-based fungal products should be tested under field conditions to confirm these laboratory results. [ABSTRACT FROM AUTHOR]

Durian (Durio zibethinus L.) is an economically important crop in the southern and eastern parts of Thailand. The occurrence of die-back disease caused by plant pathogenic fungi poses a serious threat to the quality and quantity of durian products. However, the identification of causal agents has been a subject of mixed information and uncertainty. In this research, we conducted a comprehensive investigation of die-back disease in nine durian plantations located in Thailand. By analyzing a total of 86 Fusarium isolates obtained from infected tissues, we aimed to provide clarity and a better understanding of the fungal pathogens responsible for this economically significant disease. Through a combination of colony characteristics, microscopic morphology, and a multilocus sequence analysis (MLSA) of the internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF1-α) gene, and RNA polymerase II gene (RPB2) sequences, we were able to identify and categorize the isolates into three distinct groups, namely, Fusarium incarnatum, F. solani, and F. mangiferae. Koch's postulates demonstrated that only F. incarnatum and F. solani were capable of causing die-back symptoms. This research represents the first report of F. incarnatum as a causal agent of die-back disease in durian in Thailand. Additionally, this study uncovers the association of ambrosia beetles and F. solani, highlighting the potential involvement of E. similia in facilitating the spread of die-back disease caused by Fusarium in durian. [ABSTRACT FROM AUTHOR]

Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae, Scolytinae) is a worldwide invasive species that causes huge economic loss and environmental damage in many countries. Traditional morphological characteristics make it hard to identify scolytines due to their tiny size. Besides, the intercepted insect samples are incomplete, and the limitation of insect (larvae and pupae) morphology makes morphological identification more difficult. The majority of the damage is caused by adults and fungi that serve as nutrition for their larvae. They destroy plant trunks, branches, and twigs, affecting plant transport tissues in both weak and healthy plants. An accurate, efficient, and economical molecular identification technique for X. compactus not restricted by professional taxonomic knowledge is necessary. In the present study, a molecular identification tool based on the mitochondrial DNA gene, cytochrome C oxidase subunit I (COI) was developed. A species-specific COI (SS-COI) PCR assay was designed to identify X. compactus regardless of the developmental stage. Twelve scolytines commonly found in eastern China, namely Xylosandrus compactus, X. crassiusculus, X. discolor, X. germanus, X. borealis, X. amputates, X. eupatorii, X. mancus, Xyleborinus saxesenii, Euwallacea interjectus, E. fornicatus, and Acanthotomicus suncei, were included in the study. Additionally, specimens of X. compactus from 17 different areas in China, as well as a specimen collected from the United Stated, were also analyzed. Results demonstrated the accuracy and high efficiency of the assay, regardless of the developmental stage or the type of specimen. These features provide a good application prospect for fundamental departments and can be used to prevent the harmful consequences of the spread of X. compactus. [ABSTRACT FROM AUTHOR]

By‐product mutualisms are ubiquitous yet seldom considered in models of mutualism. Most models represent conditional mutualisms that shift between mutualism and antagonism in response to shifts in costs and benefits resulting from changes in environmental quality. However, in by‐product mutualisms, benefits arise as a part of normal life processes that may be costly to produce but incur little‐to‐no additional costs in response to the interaction. Without costs associated with the interaction, they do not have antagonistic alternate states. Here, we present a conceptual model that differs from traditional conditional models in three ways: (1) partners exchange by‐product benefits, (2) interactions do not have alternate antagonistic states, and (3) tradeoffs are allowed among factors that influence environmental quality (rather than all factors that contribute to environmental quality being combined into a single gradient ranging from high to low). We applied this model to bark and ambrosia beetles (Curculionidae: Scolytinae), a diverse group that associates with fungi and that has repeatedly developed two distinct pathways to by‐product mutualism. We used independent axes for each major factor influencing environmental quality in these systems, including those that exhibit tradeoffs (tree defense and nutritional quality). For these symbioses, tradeoffs in these two factors are key to which mutualism pathway is taken. [ABSTRACT FROM AUTHOR]

The ecologically and culturally vital tree species, ʻōhiʻa lehua (Metrosideros polymorpha), is threatened by the fungal pathogens Ceratocystis lukuohia and Ceratocystis huliohia, the causal agents of the disease complex called Rapid ʻŌhiʻa Death (ROD). Four invasive ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) species in the Xyleborini tribe colonize ROD Ceratocystis‐infested 'ōhiʻa and produce inoculum through their frass; however, the potential for direct transmission of the ROD fungi by these beetles was unknown. We fulfilled Leach's rules to support insect transmission of ROD by documenting the visitation of these ambrosia beetles to healthy 'ōhiʻa trees, culturing C. lukuohia and C. huliohia from the ROD‐associated beetles using three different collection methods at multiple study sites, and challenging healthy ʻōhiʻa seedlings with beetles that were exposed to both C. lukuohia and C. huliohia cultures. We documented all four invasive ROD‐associated ambrosia beetle species including Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, and Xyleborus perforans to regularly visit healthy ʻōhiʻa trees on sticky traps. Viable Ceratocystis propagules were isolated from all species, and C. lukuohia was most commonly isolated of the two ROD‐causing fungi. Consistently across all collection techniques, ROD Ceratocystis spp. were detected on just under 3% of all assayed beetles, with the highest detection rate from X. affinis. All four beetle species were capable of directly transmitting both pathogens to healthy ʻōhiʻa seedlings with a high rate of transfer. Ceratocystis spp. are highly virulent pathogens in trees, and a single inoculation can result in tree death, therefore any direct transmission is a cause for concern. After meeting the criteria of Leach's rules, we propose that Xi. saxesenii, X. affinis, X. ferrugineus, and X. perforans are vectors of C. lukuohia and C. huliohia, particularly in areas of high ROD pressure and tree stress. [ABSTRACT FROM AUTHOR]

California has been invaded by two distinct Euwallacea spp. that vector unique plant pathogenic symbiotic fungi on multiple hosts and cause Fusarium dieback. The objective of this study was to develop multiplex real-time quantitative PCR assays using hydrolysis probes targeting the β-tubulin gene to detect, distinguish, and quantify fungi associated with the polyphagous shot hole borer (PSHB; Euwallacea whitfordiodendrus, Fusarium euwallaceae, Graphium euwallaceae, and Paracremonium pembeum) as well as the Kuroshio shot hole borer (KSHB; Euwallacea kuroshio, Fusarium kuroshium, and Graphium kuroshium) from various sample types. Absolute quantification reaction efficiencies ranged from 88.2 to 104.3%, with a coefficient of determination >0.992 and a limit of detection of 100 copies µl-1 for all targets across both assays. Qualitative detection using the real-time assays on artificially inoculated avocado shoot extracts showed more sensitivity compared with conventional fungal isolation from wood. All symbiotic fungi, except P. pembeum, from PSHB and KSHB female heads were detectable and quantified. Field samples from symptomatic Platanus racemosa, Populus spp., and Salix spp. across 17 of 26 city parks were positively identified as PSHB and KSHB through detection of their symbiotic fungi, and both were found occurring together on five trees from three different park locations. The molecular assays presented here can be utilized to accurately identify fungi associated with these invasive pests in California.

The tea shot hole borer, Euwallacea perbrevis, has been recently established in Florida, USA, where it vectors fungal pathogens that cause Fusarium dieback in avocado. Pest monitoring uses a two-component lure containing quercivorol and α-copaene. Incorporation of a repellent into IPM programs may reduce the incidence of dieback in avocado groves, particularly if combined with lures in a push–pull system. This study evaluated piperitone and α-farnesene as potential repellents for E. perbrevis, comparing their efficacy to that of verbenone. Replicate 12-week field tests were conducted in commercial avocado groves. Each test compared beetle captures in traps baited with two-component lures versus captures in traps containing lures plus repellent. To complement field trials, Super-Q collections followed by GC analyses were performed to quantify emissions from repellent dispensers field-aged for 12 weeks. Electroantennography (EAG) was also used to measure beetle olfactory response to each repellent. Results indicated that α-farnesene was ineffective; however, piperitone and verbenone were comparable in repellency, achieving 50–70% reduction in captures, with longevity of 10–12 weeks. EAG responses to piperitone and verbenone were equivalent, and significantly greater than response to α-farnesene. Since piperitone is less expensive than verbenone, this study identifies a potential new E. perbrevis repellent. [ABSTRACT FROM AUTHOR]

Fungus farming insects encounter multiple microbial threats in their cultivar gardens. They can affect both the nutritional cultivar and the insect's health. In this study, we explored the potential of ambrosia beetles and their larvae to detect the presence of antagonistic or entomopathogenic fungi. The ability to recognize a threat offers individuals a chance to react. Our study organism, the fruit-tree pinhole borer, Xyleborinus saxesenii, is associated with two mutualistic fungi, Dryadomyces sulphureus (Raffaelea sulphurea) and Raffaelea canadensis. Both symbionts were tested in combinations with two common fungus-garden weeds (Aspergillus sp. and Penicillium commune) and the entomopathogen Beauveria bassiana in two-choice experiments. Behavioural repellence was found in many, but not all combinations. Larvae and adult females showed an opposite response to the entomopathogen, whereas for Aspergillus sp., neither provoked repellence nor attraction of larvae and adult females, if R. canadensis was used as lure. Our results validate a response of both larvae and adult ambrosia beetles towards other fungal volatiles. Their decision to confront a potential threat or preferably to avoid it could be subject to a more complex context. [ABSTRACT FROM AUTHOR]

Ship-timber beetles (Coleoptera: Lymexylidae) are associated with wood-inhabiting fungi. The female adults of the genus Elateroides possess fungus-carrying organs (so-called mycetangia) at the ovipositor and deposit fungal symbionts of the genus Alloascoidea onto wood during oviposition. The larvae grow by feeding on the fungi proliferating on the walls of tunnels that the larvae made in wood. Thus, in the fungus-growing mutualism practiced by Elateroides species, it has been considered that the beetles' partners are Alloascoidea fungi. However, to date, lymexylid-associated fungal communities have been poorly documented. Here, I report that E. dermestoides originating from Japan harbored at least nine fungal species. When microbial isolation was conducted from mycetangia of five female adults of E. dermestoides, colonies of filamentous fungi and yeasts were recovered. DNA analyses revealed that they were Candida boleticola, Cosmospora berkeleyana, Kuraishia floccosa, and undescribed fungi of the genera Alloascoidea, Ambrosiozyma, Ca. mesenterica-related Candida, Ca. palmyrensis-related Candida, Cyberlindnera, and Ogataea. Of those, Alloascoidea sp., Cyberlindnera sp., and Ogataea sp. were frequently isolated (80–100%), while the others showed low isolation rates, suggesting that these three fungal species are closely associated with E. dermestoides. The findings strongly suggest that multiple fungal species including Alloascoidea are involved in the life history of lymexylids. [ABSTRACT FROM AUTHOR]

Abstract By‐product mutualisms are ubiquitous yet seldom considered in models of mutualism. Most models represent conditional mutualisms that shift between mutualism and antagonism in response to shifts in costs and benefits resulting from changes in environmental quality. However, in by‐product mutualisms, benefits arise as a part of normal life processes that may be costly to produce but incur little‐to‐no additional costs in response to the interaction. Without costs associated with the interaction, they do not have antagonistic alternate states. Here, we present a conceptual model that differs from traditional conditional models in three ways: (1) partners exchange by‐product benefits, (2) interactions do not have alternate antagonistic states, and (3) tradeoffs are allowed among factors that influence environmental quality (rather than all factors that contribute to environmental quality being combined into a single gradient ranging from high to low). We applied this model to bark and ambrosia beetles (Curculionidae: Scolytinae), a diverse group that associates with fungi and that has repeatedly developed two distinct pathways to by‐product mutualism. We used independent axes for each major factor influencing environmental quality in these systems, including those that exhibit tradeoffs (tree defense and nutritional quality). For these symbioses, tradeoffs in these two factors are key to which mutualism pathway is taken.

The polyphagous shot hole borer (Euwallacea nr. fornicatus, Coleoptera: Curculionidae: Scolytinae), an exotic and invasive ambrosia beetle, was recently found attacking a number of tree species in Los Angeles, Orange, Riverside, and San Diego Counties in southern California. Their colonization and subsequent inoculation of a suite of symbiotic fungi that cause Fusarium Dieback, has resulted in extensive mortality of some tree species, including, California sycamore (Platanus racemose Nutt.). There are no sustainable control options for polyphagous shot hole borer other than maintaining tree vigor and removal of severely infested host material. The effectiveness of therapeutic treatments of an injected systemic insecticide containing emamectin benzoate (EB) alone and in combination with a systemic fungicide, propiconazole (P), was evaluated over a 4-yr period for maintaining the health of individual sycamore trees infested by polyphagous shot hole borer. All treatments containing EB reduced levels of polyphagous shot hole borer colonization and associated sap flow at attack sites compared to untreated controls. A second trial evaluated preventative treatments of EB and P alone or combined to protect individual sycamore from colonization by polyphagous shot hole borer. After 45 mo posttreatment, all treatments significantly reduced polyphagous shot hole borer attack levels and successful attacks compared to untreated controls (EB + P > EB alone > P alone). We concluded that EB alone or combined with P are acceptable therapeutic and preventative treatments for management of polyphagous shot hole borer in California sycamore in southern California.

Ambrosia beetles of the Euwallacea fornicatus species complex are emerging tree pests with a broad host range including important agricultural crops. Native to Southeast Asia, these species were introduced into various countries, where they cause considerable damage to many tree species. Here we report several outbreaks of E. fornicatus s.l. in Europe. The first individuals were found in 2017 in a palm house of a botanical garden in Poznan (Poland) whereas in 2020 an outbreak was detected in a tropical greenhouse in Merano (Italy). In 2021, two additional outbreaks were detected in two greenhouses in Germany, in Erfurt and Berlin. For both cases in Germany it was possible to trace back the invasion to a distributor of exotic plants in the Netherlands where several infested plants were detected. Molecular analyses show that individuals from Poland and Italy are genetically identical but belong to a different mitochondrial clade than individuals in Germany which are identical to most individuals of two greenhouses in the Netherlands. Moreover, in the two greenhouses in the Netherlands we found beetles that belong to another haplotype of E. fornicatus and two haplotypes of E. perbrevis, a species in the E. fornicatus complex, which has not been previously intercepted in Europe. Our study provides novel insights into the invasion history of E. fornicatus and the eradication measures in Europe. Considering the potential of introduction and establishment of Euwallacea ambrosia beetles, particular attention should be paid to monitor the presence of these pests in tropical greenhouses across Europe. [ABSTRACT FROM AUTHOR]

Laurel wilt is a lethal disease of American Lauraceae caused by Harringtonia lauricola. Propiconazole is a systemic fungicide which arrests fungal growth among a variety of plant hosts. Propiconazole as a preventive treatment against laurel wilt in sassafras (Sassafras albidum) has not been evaluated. We treated sassafras trees with propiconazole using the Arborjet QUIK-jet® Micro-InjectionTM and TREE I.V. MicroInfusionTM systems (Arborjet,Inc., Woburn, MA, USA) and challenged trees by inoculating them with H. lauricola. Out of 7 trees treated using the QUIK-jet Micro-Injection system, 6 (86%) survived 52 or more weeks following inoculation with H. lauricola, while only 11% of inoculated control trees (1 of 9) survived over this period. All trees not damaged by hurricanes (n = 13) treated with propiconazole using the TREE I.V. Micro-Infusion system survived significantly longer than untreated control trees after inoculation with H. lauricola; 10 of 13 trees (77%) survived with < 50% crown loss, and 8 of 13 trees (62%) appeared entirely healthy 54 weeks post-inoculation. In the TREE I.V. Micro-Infusion system trial, 15 of 19 control trees (79%) had either died or lost ≥ 50% of living crown 54 weeks post-inoculation with H. lauricola. Results indicate sassafras trees treated with propiconazole using the Arborjet QUIK-jet Micro-Injection and TREE I.V. Micro-Infusion systems are significantly less likely to die within one year of infection with H. lauricola; however some trees may exhibit significant crown decline (≥ 50%) over this period. [ABSTRACT FROM AUTHOR]

The shot hole borer (SHB), Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae: Scolytinae), is an emerging pest of Robusta coffee in India. Traps with attractants are commonly used to capture the ambrosia beetles for purposes of monitoring, studying population dynamics, predicting outbreaks, and mass trapping to reduce damage. The relative attractiveness of several common attractants and the influence of their concentration were evaluated in the field against X. compactus using Broca traps in this study. The tested attractants exhibited clear differences in attractiveness and the preliminary field studies at coffee plantations revealed that absolute ethanol attracted more shot hole borer adults than coffee twig extracts, distillery ethanol, and ethanol methanol combinations. The number of beetles trapped varied in different places during multi-location field trials, but in general, 50% of absolute ethanol-baited traps captured the highest number of beetles in all the locations. This study demonstrates 50% absolute ethanol can be used as an effective attractant for coffee shot hole borer and enables a cost-effective option for the control of X. compactus in coffee. [ABSTRACT FROM AUTHOR]

Ambrosia beetles are the largest group of beetles living mutualistically with ambrosia fungi. Increased global shipments of forest and agricultural products have expanded the distribution of some species of ambrosia beetle. We investigated the partitioning diversity of the ambrosia beetle community on teak plantations in Indonesia's Java, Sumbawa, and Sulawesi Islands. The ambrosia beetles were collected on the twelve sites of teak plantations with different managements (un-thinned and thinned) in Java, Sulawesi, and Sumbawa Islands. Ambrosia beetles were collected ten times at 7-day intervals. The diversity of ambrosia beetles recorded in teak plantations across twelve sites in Java, Sumbawa, and Sulawesi Islands were 17 species and 6154 individuals. Xyleborus affinis (47.17%), Xylosandrus crassiusculus (27.64%), and Hypothenemus sp. (12.33%) were the three dominant species. The highest and lowest species richness were found in the teak plantations in Java and Sumbawa Islands, respectively. The highest and lowest populations of ambrosia beetles were in Sulawesi and Sumbawa islands, respectively. Three factors contribute to the species richness of ambrosia beetles, i.e., temperature, rainfall, and altitude. Stand age, temperature, rainfall, altitude, and teak management contribute to ambrosia beetle abundance. Ambrosia beetle communities among islands show differences between each group, as confirmed by analysis of variance based on homogeneity of multivariate dispersion (sig. 0.001) and permutation test for homogeneity of multivariate dispersions (sign. 0.001). For the group of teak managements, there are differences between both teak managements, as confirmed by analysis of variance based on homogeneity of multivariate dispersion (sig. 0.001) and permutation test for homogeneity of multivariate dispersions (sign. 0.01). Based on the eigenvalues for PCoA axes by the Bray–Curtis method, Sulawesi Island is separate from both Java, and Sumbawa islands. However, Java and Sumbawa islands overlap each other. For groups of teak managements (thinning and non-thinning), there are overlap with each other based on the eigenvalues for PCoA axes by the Bray–Curtis method. The β-1 (Within bottle trap/local scale) contributes the highest to γ-diversity (42.46%). The relative contribution of species replacement (β-sim) in multiple sites across Java, Sumbawa, and Sulawesi Islands (regional scale) provides a high contribution (85%) to overall beta diversity, and the relative contribution of β-nes to the β-sor among sites is 14.03%. [ABSTRACT FROM AUTHOR]

The Euwallacea fornicatus species complex (Coleoptera: Curculionidae: Scolytinae: Xyleborini) is a group of four cryptic ambrosia beetle species. Native to Asia, several members of the complex have invaded other continents, where they cause significant economic losses to agricultural crops (e.g., avocado) and natural ecosystems. We were primarily interested in developing management strategies by focusing on the flight behavior of the beetles. Thus, seasonal differences in flight activity were assessed using panel traps baited with a commercial quercivorol lure, placed in infested avocado orchards in Danei, Tainan, Taiwan. Same traps were used to investigate the flight activity of a natural enemy, an undescribed species of the Braconid genus Eucosmophorus sp. Shothole borer species were identified using a DNA-based, high resolution melting assay. Trap data were compared to the predictions of a simple degree-day model, incorporating developmental data and several environmental parameters known to influence flight. Such as the time period representing most of flight activity in a day and temperature-dependent flight propensity. In stark contrast to the degree-day model which predicted the highest emergence, and by extension flight, of shothole borers during spring and summer (May to November), flight activity was actually lowest during these months, and instead, peaked during the winter (October to March). Abundance of the parasitoid wasp closely mirrored flight activity of the shothole borers. The mismatch of trapping and modeling data can have many causes, heavy precipitation and possibly cooperative brood care may suppress the dispersal behavior of the shothole borers during the summer. [ABSTRACT FROM AUTHOR]

Summary: Two Ruehmaphelenchus species were isolated from the ambrosia beetles Euwallacea kuroshio and E. interjectus , collected from Okinawa and Kagoshima, Japan, respectively. Both nematodes were successfully cultured on a lawn of the grey mould Botrytis cinerea. Morphological observation and molecular characterisation revealed that both species are undescribed; therefore, the nematodes are described herein as R. kuroshioi n. sp. and R. interjectus n. sp. Phylogenetically, both species are closely related to R. formosanus , R. fujiensis , R. digitulus and R. asiaticus. Ruehmaphelenchus kuroshioi n. sp. is characterised by a conical male and female tail, which has a terminal projection (mucron), small male spicule with a weakly-developed triangular condylus, dorsal and ventral limbs that are connected to each other by three different tissues, and clearly separated distal pairs of genital papillae (P3 and P4). However, R. kuroshioi n. sp. can be distinguished from its close relatives by a combination of male and female tail characters and its distinctive phylogenetic status. Ruehmaphelenchus interjectus n. sp. is almost identical to R. formosanus , sharing characteristic lateral spikes of the spicule; they form a well-supported phylogenetic clade. However, R. interjectus n. sp. is distinguished from R. formosanus by morphometric values and ribosomal RNA, i.e. , a 6-bp difference from the ca 1.7 kb molecular sequence of the 18S ribosomal RNA of R. formosanus , which warrants independent species status. [ABSTRACT FROM AUTHOR]

Although the attacks of I X. crassiusculus i on cocoa pods were similar to those recently recorded on areca nuts [[18]], the modest number of plants attacked suggests that spermatophagy on cocoa pods is sporadic. Hence, an infestation of I X. crassiusculus i with fungal symbionts could interfere in the fermentation process of fresh cocoa beans and ultimately affect the marketable quality of dry cocoa beans. However, all the concealed damage symptoms (appearance of galleries inside pod husk, mucilage, and beans, and the location of immature stages of the pest within the infested pods) were systematically recorded after cutting open the infested pods ( I n i = 20) in the laboratory. Graph: Figure 6 (a) adult X. crassiusculus boring on an immature cocoa bean; (b) adult X. crassiusculus tunneling on mature cocoa bean; (c) staining of insect galleries with whitish-grey fungal hyphae; (d) eggs of X. crassiusculus with fungal symbionts in cocoa bean. [Extracted from the article]

Introduction With 84 worldwide distributed species in 19 genera (including fossils), Lymexylidae is divided into four subfamilies: Atractocerinae (nine genera, with three extinct), Hylecoetinae (one genus), Lymexylinae (one genus), and Melittommatinae (five genera, with one extinct) [[1], [3], [5], [7]]. 1967: 141-205 32 Toki W. A single case study of mycetangia-associated fungi and their abilities to assimilate wood-associated carbon sources in the ship timber beetle Elateroides flabellicornis (Coleoptera: Lymexylidae) in Japan. Keywords: Atractocerinae; Cretoquadratus; Kachin amber; ambrosia beetle EN Atractocerinae Cretoquadratus Kachin amber ambrosia beetle N.PAG N.PAG 9 09/27/22 20220901 NES 220901 1. [Extracted from the article]

Euwallacea perbrevis, the tea shot-hole borer (TSHB), is an invasive ambrosia beetle that vectors several fungal pathogens that cause Fusarium branch dieback in avocado trees in southern Florida. This study assessed the potential of four commercial products containing the entomopathogenic fungus Beauveria bassiana (Bb) for managing adult TSHB beetles. Formulated products containing Bb strains to which adult beetles were exposed were BioCeres WP, BotaniGard WP, BotaniGard ES, and Velifer ES. Controls consisted of water only and BotaniGard ES and Velifer ES supernatant with spores removed. Acquisition of spores by adult beetles dipped in product suspensions with 2.5 ± 0.1 × 106 spores/mL was assessed. Survival time of beetles after residual exposure to the Bb-based products in an in vivo avocado bark plug bioassay was determined. Production of Bb spores on beetles after being dipped in product suspensions and placed in a moistened bark-plug assay with water only was assessed. Significantly more spores were acquired by beetles exposed to Velifer ES and BotaniGard ES than beetles exposed to the other fungal products. Beetles exposed to Velifer ES and BotaniGard ES died faster (6–8 days) compared to beetles dipped in the other fungal products (10–11 days) and controls (12 days). Percentage of mycosis was highest with beetles exposed to Velifer ES (63%). Spore production on cadavers of beetles dipped in Velifer ES (20 ± 6.4 × 105 spores/cadaver) was the highest among all treatments, whereas it was the lowest on cadavers of beetles dipped in BotaniGard ES (1 ± 0.2 × 105 spores/cadaver). All Bb-based products, especially Velifer ES, demonstrated potential to manage TSHB populations under laboratory conditions. These Bb-based fungal products should be tested under field conditions to confirm these laboratory results.

Durian (Durio zibethinus L.) is an economically important crop in the southern and eastern parts of Thailand. The occurrence of die-back disease caused by plant pathogenic fungi poses a serious threat to the quality and quantity of durian products. However, the identification of causal agents has been a subject of mixed information and uncertainty. In this research, we conducted a comprehensive investigation of die-back disease in nine durian plantations located in Thailand. By analyzing a total of 86 Fusarium isolates obtained from infected tissues, we aimed to provide clarity and a better understanding of the fungal pathogens responsible for this economically significant disease. Through a combination of colony characteristics, microscopic morphology, and a multilocus sequence analysis (MLSA) of the internal transcribed spacer (ITS) region, translation elongation factor 1-α (TEF1-α) gene, and RNA polymerase II gene (RPB2) sequences, we were able to identify and categorize the isolates into three distinct groups, namely, Fusarium incarnatum, F. solani, and F. mangiferae. Koch’s postulates demonstrated that only F. incarnatum and F. solani were capable of causing die-back symptoms. This research represents the first report of F. incarnatum as a causal agent of die-back disease in durian in Thailand. Additionally, this study uncovers the association of ambrosia beetles and F. solani, highlighting the potential involvement of E. similia in facilitating the spread of die-back disease caused by Fusarium in durian.

The ambrosia beetle Euwallacea fornicatus (Polyphagous Shot Hole Borer; PSHB), native to Asia, was documented in South Africa for the first time in 2012. Death of susceptible host trees is caused by blocking of xylem tissues by the mutualistic plant-pathogenic fungus, Fusarium euwallaceae and extensive tunnelling by the beetles into the sapwood. Within a few years, PSHB has spread from its putative entrance point in the coastal province of KwaZulu-Natal to nearly every other province in South Africa. This study serves as a preliminary assessment of dispersal pathways and population genetic relationships of PSHB in South Africa. PSHB individuals were collected from five provinces across South Africa. In addition, data on PSHB from three provinces in its native range in China and invasive PSHB from California were also generated here and supplemented by sequence data of PSHB available from GenBank. Comparisons of Cytochrome Oxidase Subunit I (COI) sequences of PSHB in South Africa revealed a nearly homogenous population. The majority of individuals have the same haplotype as is present in California, Israel and Vietnam (H33). A second haplotype was present in only two localities in KwaZulu-Natal and the Western Cape. This haplotype is also present in Vietnam and China (H38). The placement of the two haplotypes identified within South Africa, into different haplogroups suggests more than one invasion event. This pilot project justifies the use of more comprehensive genomic tools to finely map the relationships, global invasion pathways and within-country dispersal patterns of PSHB to better inform management of this invasive species. [ABSTRACT FROM AUTHOR]

Studies addressing the economic impacts of invasive alien species are biased towards ex-post assessments of the costs and benefits of control options, but ex-ante assessments are also required to deal with potentially damaging invaders. The polyphagous shot hole borer Euwallacea fornicatus (Coleoptera: Curculionidae) is a recent and potentially damaging introduction to South Africa. We assessed the potential impact of this beetle by working across economic and biological disciplines and developing a simulation model that included dynamic mutualistic relations between the beetle and its symbiotic fungus. We modeled the potential growth in beetle populations and their effect on the net present cost of damage to natural forests, urban trees, commercial forestry, and the avocado industry over 10 yr. We modeled high, baseline, and low scenarios using discount rates of 8, 6, and 4%, and a plausible range of costs and mortality rates. Models predicted steady growth in the beetle and fungus populations, leading to average declines in tree populations of between 3.5 and 15.5% over 10 yr. The predicted net present cost was 18.45 billion international dollars (Int. $), or about 0.66% of the country's GDP for our baseline scenario ($2.7 billion to $164 billion for low and high scenarios). Most of the costs are for the removal of urban trees that die as a result of the beetle and its fungal symbiont, as has been found in other regions. We conclude that an ex-ante economic assessment system dynamics model can be useful for informing national strategies on invasive alien species management. [ABSTRACT FROM AUTHOR]

Gnathotrichus materiarius (Fitch, 1858) is an alien ambrosia beetle from North America, that has been spreading across Europe since the 1930s. The species infests coniferous trees, excavating galleries in sapwood. However, to date very few studies have predicted changes in ambrosia beetle habitat suitability under changing climate conditions. To fill that gap in the current knowledge, we used the MaxEnt algorithm to estimate areas potentially suitable for this species in Europe, both under current climate conditions and those forecasted for the years 2050 and 2070. Our analyses showed areas where the species has not been reported, though the climatic conditions are suitable. Models for the forecasted conditions predicted an increase in suitable habitats. Due to the wide range of host trees, the species is likely to spread through the Balkans, the Black Sea and Caucasus region, Baltic countries, the Scandinavian Peninsula, and Ukraine. As a technical pest of coniferous sapwood, it can cause financial losses due to deterioration in quality of timber harvested in such regions. Our results will be helpful for the development of a climate-change-integrated management strategy to mitigate potential adverse effects. [ABSTRACT FROM AUTHOR]

Native to Southeastern Asia, the ambrosia beetle Xylosandrus compactus is invasive worldwide. Its invasion is favoured by its cryptic lifestyle, symbiosis with a fungus that facilitates a broad range of host plants, and predominant sib-mating reproduction. X. compactus invaded Africa more than a century ago and the Americas and Pacific Islands in the middle of the twentieth century. It was not detected in Europe before 2011, when it was first reported in Italy before quickly spreading to France, Greece and Spain. Despite the negative environmental, agricultural and economic consequences of the invasion of X. compactus, its invasion history and main pathways remain poorly documented. We used COI and RAD sequencing to (i) characterise the worldwide genetic structure of the species, (ii) disentangle the origin(s) of the non-native populations on the three invaded continents and (iii) analyse the genetic diversity and pathways within each invaded region. Three mitochondrial lineages were identified in the native range. Populations invading Europe and the American-Pacific region originated from the first lineage and were only slightly genetically differentiated at nuclear SNP markers, suggesting independent introductions from close sources in or near Shanghai, ca. 60 years apart. Populations invading Africa originated from the second lineage, likely from India or Vietnam. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Plant Health performed a pest categorisation of Platypus apicalis (Coleoptera: Curculionidae: Platypodinae), an ambrosia beetle, also known as a pinhole borer, for the EU territory. P. apicalis is a polyphagous pest native to New Zealand. The majority of its life cycle is spent inside tree wood, but it does not directly feed on plant tissue, instead larvae and adults feed on a symbiotic fungus (Sporothrix nothofagi which is pathogenic to Nothofagus spp.) vectored by adults and introduced when they bore tunnels into the host. P. apicalis feeds within a wide range of live, often stressed trees, in dead or dying hardwood and softwood trees, and fallen or felled trees. Successful reproduction can occur inside a number of living tree species including Castanea sativa, Pinus spp. and Ulmus spp. P. apicalis is not known to have established outside of New Zealand although findings have been reported in Australia. Whilst there are no records of interceptions of this species in the EU, platypodines are intercepted with solid wood packing material (SWPM) and Platypus species, but not P. apicalis, have been intercepted with wooden logs in Japan. Host plants for planting also provide a potential pathway. Hosts are grown widely across the EU in areas with climates comparable to those in New Zealand where the pest occurs suggesting that conditions in the EU are suitable for its establishment. If introduced into the EU, adults could disperse naturally by flight, perhaps tens or hundreds of metres. The movement of infested wood and host plants for planting within the EU could facilitate spread. Economic impacts in forestry and timber industries would result from the galleries created by P. apicalis and from wood staining caused by the symbiotic fungus. Phytosanitary measures are available to inhibit the entry of P. apicalis. P. apicalis satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. [ABSTRACT FROM AUTHOR]

Oak decline syndrome has been observed in South Korea and Japan and variously referred to as Korean oak wilt (KOW) and Japanese oak wilt (JOW). We reviewed aspects of the historical occurrence of KOW, disease cycle, and its potential causes. KOW has been seen principally in Mongolian oak (Quercus mongolica Fisch. ex Ledeb.). The first occurrence of KOW was in 2004 in Seongnam, South Korea. KOW is associated with the fungus Raffaelea quercus-mongolicae, which is vectored by the ambrosia beetle Platypus koryoensis. In addition, it has been suggested that yeasts have evolved a symbiotic relationship with the vector without antagonism for the pathogenic fungus. The number of trees in Korea killed by KOW increased to about 331,000 in 2011, but then decreased to about 157,000 in 2019. We hypothesized that trees infected by R. quercus-mongolicae accumulate phenolic compounds in the sapwood and the vector (P. koryoensis) beetles then avoid these trees. Therefore, the number of hosts available for the beetle after a KOW outbreak decrease due to accumulation of phenolic compounds in the wood, although most oak trees survive outbreaks. Therefore, P. koryoensis beetles move longer distances after outbreaks to find susceptible host trees. Novel occurrence of KOW in Korea may be due to either (1) an increase in tree age (size) in Korean oak stands, for which the beetle has a known preference or (2) climate change, which may be increasing the number of weakened or stressed trees, for which P. koryoensis also shows a preference. [ABSTRACT FROM AUTHOR]

Abstract The EFSA Panel on Plant Health performed a pest categorisation of Platypus apicalis (Coleoptera: Curculionidae: Platypodinae), an ambrosia beetle, also known as a pinhole borer, for the EU territory. P. apicalis is a polyphagous pest native to New Zealand. The majority of its life cycle is spent inside tree wood, but it does not directly feed on plant tissue, instead larvae and adults feed on a symbiotic fungus (Sporothrix nothofagi which is pathogenic to Nothofagus spp.) vectored by adults and introduced when they bore tunnels into the host. P. apicalis feeds within a wide range of live, often stressed trees, in dead or dying hardwood and softwood trees, and fallen or felled trees. Successful reproduction can occur inside a number of living tree species including Castanea sativa, Pinus spp. and Ulmus spp. P. apicalis is not known to have established outside of New Zealand although findings have been reported in Australia. Whilst there are no records of interceptions of this species in the EU, platypodines are intercepted with solid wood packing material (SWPM) and Platypus species, but not P. apicalis, have been intercepted with wooden logs in Japan. Host plants for planting also provide a potential pathway. Hosts are grown widely across the EU in areas with climates comparable to those in New Zealand where the pest occurs suggesting that conditions in the EU are suitable for its establishment. If introduced into the EU, adults could disperse naturally by flight, perhaps tens or hundreds of metres. The movement of infested wood and host plants for planting within the EU could facilitate spread. Economic impacts in forestry and timber industries would result from the galleries created by P. apicalis and from wood staining caused by the symbiotic fungus. Phytosanitary measures are available to inhibit the entry of P. apicalis. P. apicalis satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

The tea shot hole borer, Euwallacea perbrevis, has been recently established in Florida, USA, where it vectors fungal pathogens that cause Fusarium dieback in avocado. Pest monitoring uses a two-component lure containing quercivorol and α-copaene. Incorporation of a repellent into IPM programs may reduce the incidence of dieback in avocado groves, particularly if combined with lures in a push–pull system. This study evaluated piperitone and α-farnesene as potential repellents for E. perbrevis, comparing their efficacy to that of verbenone. Replicate 12-week field tests were conducted in commercial avocado groves. Each test compared beetle captures in traps baited with two-component lures versus captures in traps containing lures plus repellent. To complement field trials, Super-Q collections followed by GC analyses were performed to quantify emissions from repellent dispensers field-aged for 12 weeks. Electroantennography (EAG) was also used to measure beetle olfactory response to each repellent. Results indicated that α-farnesene was ineffective; however, piperitone and verbenone were comparable in repellency, achieving 50–70% reduction in captures, with longevity of 10–12 weeks. EAG responses to piperitone and verbenone were equivalent, and significantly greater than response to α-farnesene. Since piperitone is less expensive than verbenone, this study identifies a potential new E. perbrevis repellent.

The insect pinhole borer, Euplatypus sp., infests rubber tree trunks and induce bleeding symptom which is different to that caused by the fungal pathogen Lasiodiplodia theobromae (Pat. Griff. & Maubl.). Pinholes are very prominent as the insect bore the trunk and exudates of latex are very noticeable in the infested trunk portion. The borer would extend its damage until the sapwood of the tree, leaving a powder-like sawdust in the ground. The death of the pinhole borer-infested trees is very likely to happen if remedial insecticide application cannot be instituted immediately. In addition, the fungus L. theobromae and an unknown bacterium were found associated with the pinhole borer. [ABSTRACT FROM AUTHOR]

Ambrosia beetles are an emerging threat to forestry ecosystems, attacking native and non-native trees. The brazilwood (Paubrasilia echinata (Lam.) Gagnon, H.C.Lima & G.P.Lewis) is currently considered the most appropriate material for the manufacture of violin bows due to its unique vibrational properties. An experimental plantation of brazilwood has been attacked by the ambrosia beetle Megaplatypus mutatus Chapuis. In this work, we compared the cell wall carbohydrate composition of brazilwood sawdust produced due to the attack of imagoes (adult males) and larvae of this beetle. We aimed to assess changes caused by the insect and its associated microbiota. Cellulose and xylans represented the main fractions of all materials, and pectin accounted for only 10-15% of the walls. The yield of wall fractions and cell wall composition of the sawdust produced by adult beetles, which is composed of long particles, were quite similar to those found in the material obtained from uninfected trunks indicating that the adult male does not feed on the wood at this stage. In contrast, chemical fractionation of the granular sawdust from larvae showed a lower content of extractable pectins, representing only 50% of the total amount detected in the sawdust produced by adult male beetles. Sugar composition analysis of the pectin fractions of the larval sawdust revealed the loss of arabinosyl, galacturonosyl, and galactosyl residues, indicating that the association between beetle/ambrosia fungus evolves towards the degradation of easily accessible pectic polysaccharides of the cell wall. [ABSTRACT FROM AUTHOR]

Summary: Two new Neomisticius species, typologically and phylogenetically close to each other, are described and illustrated from dead Quercus trees and an ambrosia beetle, Platypus quercivorus. The two species share some stylet morphological characteristics, namely, they both possess a long conus occupying more than half of the total stylet length, a long crustaformeria composed of more than 160 cells (eight rows of more than 20 cells each), and a short and broad female tail with a digitate tip. They are distinguished from each other by N. variabilis n. sp. having a wide, spindle-shaped male bursa with a blunt terminus and N. platypi n. sp. having an oval bursa with a rounded terminus. In addition, the males and females of both species have three large rectal glands and the posterior end of the male testis (distal end of the vas deferens) bears three cells that seemingly function as a valve between the vas deferens and the cloacal tube. These characteristics have not been reported in other tylenchids. Currently, the genus contains only three species: the two new species and N. rhizomorphoides , which has a normal stylet with a short conus, a short crustaformeria, and lacks rectal glands and valve cells in the vas deferens. Therefore, the two new species are readily distinguished from N. rhizomorphoides and, based on the previous definition, may even represent a new genus. However, considering their phylogenetic closeness and biological similarities (e.g. , association with ambrosia beetles), the generic definition of Neomisticius was emended to include these new species. [ABSTRACT FROM AUTHOR]

The black twig borer Xylosandrus compactus, an ambrosia beetle native to Asia, was recorded for the first time in Europe in 2011 in central Italy. This paper reports the progressive dispersal of this invasive species in many Italian regions (Campania 2011, Tuscany and Liguria 2012, Lombardy 2015, Lazio and Sicily 2016, Emilia Romagna 2018, Veneto 2019) and other European countries (France 2015, Spain and Greece 2019). The main features of the biology and ecology are reported, and the infestation symptoms and the produced damages are descripted, as well. An updated list of the potential host-plants is also provided. Finally, protocols for the pest control are suggested.