Ambrosia Beetle Research Articles

Pathogenicity of Bacillus subtilis Against Symbiotic Fungus of Euwallacea fornicates (Coleoptera: Scolytidae) From South India.

In India, the shot-hole borer, Euwallacea fornicates, commonly known as the tea borer, infests the galleries of tea plant twigs under natural conditions and is a major pest of tea. The current investigation focuses on the antagonistic ability of Bacillus subtilis to directly inhibit the growth of plant pathogens in two different climatic regions of tea-growing area. The evaluation reveals that (a) B. subtilis can directly suppress the growth of plant pathogens (b) in the in vitro evaluation; the B. subtilis suppressed the growth of the Fusarium ambrossium, which is the nourishment for the ambrosia beetle, (c) it also revealed that the antagonistic microbes and the entomopathogens are able to control the pest population of the shot hole borer of tea. The impact of B. subtilis on mycelial growth, sporulation, and spore germination of F. ambrosium in agar medium was observed. In the field condition on the post-treatment assessments shows an average decline of 40% in both foliar and soil drenching. Hence, we recommend the antagonistic bacterium B. subtilis for including as an IPM for the management of shot hole borer in tea.

Chromosome structural rearrangements in invasive haplodiploid ambrosia beetles revealed by the genomes of Euwallacea fornicatus (Eichhoff) and Euwallacea similis (Ferrari) (Coleoptera, Curculionidae, Scolytinae).

Bark and ambrosia beetles are among the most ecologically and economically damaging introduced plant pests worldwide. Life history traits including polyphagy, haplodiploidy, inbreeding polygyny and symbiosis with fungi contribute to their dispersal and impact. Species vary in their interactions with host trees, with many attacking stressed or recently dead trees, such as the globally distributed E. similis (Ferrari). Other species, like the Polyphagous Shot Hole Borer (PSHB) Euwallacea fornicatus (Eichhoff), can attack over 680 host plants and is causing considerable economic damage in several countries. Despite their notoriety, publicly accessible genomic resources for Euwallacea Hopkins species are scarce, hampering our understanding of their invasive capabilities as well as modern control measures, surveillance and management. Using a combination of long and short read sequencing platforms we assembled and annotated high quality (BUSCO > 98% complete) pseudo-chromosome level genomes for these species. Comparative macro-synteny analysis identified an increased number of pseudo-chromosome scaffolds in the haplodiploid inbreeding species of Euwallacea compared to diploid outbred species, due to fission events. This suggests that life history traits can impact chromosome structure. Further, the genome of E. fornicatus had a higher relative proportion of repetitive elements, up to 17% more, than E. similis. Metagenomic assembly pipelines identified microbiota associated with both species including Fusarium fungal symbionts and a novel Wolbachia strain. These novel genomes of haplodiploid inbreeding species will contribute to the understanding of how life history traits are related to their evolution and to the management of these invasive pests.

Ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) responses to ice storm damage in mesic, mixed deciduous forests in southeast Ohio, United States

Ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) responses to ice storm damage in mesic, mixed deciduous forests in southeast Ohio, United States

Fusarium species associated with Euwallacea xanthopus in South Africa, including two novel species

ABSTRACT Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are small wood-boring insects that live in an obligate symbiosis with fungi, which serve as their primary food source. Beetles residing in the genus Euwallacea have evolved a unique association with a clade of Fusarium that falls within the aptly named Ambrosia Fusarium Clade (AFC). The discovery of the invasive polyphagous shot hole borer, E. fornicatus, in South Africa, has heightened awareness of ambrosia beetles and their symbionts in the country. In this study, we investigated the Fusarium symbionts of three species of Euwallacea in South Africa, with a specific focus on those associated with E. xanthopus. Isolations of Fusarium strains from both living and dissected beetles yielded nearly 100 isolates. Using multigene phylogenetic analyses, these isolates were identified as six different Fusarium species. Fusarium hypothenemi and F. euwallaceae have previously been reported from South Africa. Fusarium pseudensiforme and Fusarium AF-6 are new records for the country. The remaining two species are new to science and are described here as F. rufum sp. nov. and F. floriferum sp. nov. Targeted fungal isolation from specific beetle body parts revealed that the AFC species collected were typically associated with the dissected beetle heads and helped us identify the likely nutritional symbiont of E. xanthopus. This study highlights the understudied diversity of fungal associates of ambrosia beetles present in South Africa.

Annotated Checklist of Armenian Platypodinae and Scolytinae (Coleoptera: Curculionidae)

The paper presents a checklist of the bark and ambrosia beetles (Curculionidae: Platypodinae and Scolytinae) of Armenia. The fauna is comprised of one Platypodinae and Scolytinae 73 species, among which four species, Lymantor coryli (Perris, 1855), Ips typographus (Linnaeus, 1758), Orthotomicus erosus (Wollaston, 1857) and Scolytus eichhoffi Reitter, 1895 are recorded for the country for the first time. Sixty one species records are also provided for Armenia which were not mentioned in recent Catalogues of Palaearcic Curculionoidea.

The Biology, Impact, and Management of Xyleborus Beetles: A Comprehensive Review.

Xyleborus beetles, a diverse group of ambrosia beetles, present challenges to forestry and agriculture due to their damaging burrowing behavior and symbiotic relationships with fungi. This review synthesizes current knowledge on the biology, ecology, and management of Xyleborus. We explore the beetles' life cycle, reproductive strategies, habitat preferences, and feeding habits, emphasizing their ecological and economic impacts. Control and management strategies, including preventive measures, chemical and biological control, and integrated pest management (IPM), are critically evaluated. Recent advances in molecular genetics and behavioral studies offer insights into genetic diversity, population structure, and host selection mechanisms. Despite progress, managing Xyleborus effectively remains challenging. This review identifies future research needs and highlights innovative control methods, such as biopesticides and pheromone-based trapping systems.

Phylogeography of the ambrosia beetle Euwallacea interjectus (Coleoptera: Curculionidae: Scolytinae): an emerging poplar pest and its Fusarium mutualists from poplar plantations in China.

Native to Asia, Euwallacea interjectus (Blandford) (Coleoptera: Curculionidae: Scolytinae) is a destructive and invasive pest of live trees, and now it has been found in the United States and Argentina. In recent years, this pest appeared in high densities in poplar monocultures from Eastern China (Jiangsu and Shanghai) and Argentina and caused significant poplar mortality. However, the origin of the pests related to tree damage and the Fusarium mutualists from some poplar zones in China remained unclear. Here, we provided a broader phylogeographic analysis of E. interjectus based on the mitochondrial gene (cytochrome c oxidase I) to determine the global genetic structure of this species. Five mitochondrial lineages were found in the native area. Populations introduced to the United States were originated from 4 localities. The Argentine population was derived from Japan. The species was observed with strikingly high level of cytochrome c oxidase I intraspecific divergence that exceeded interspecific divergence, but the high intraspecific variation was correlated with geographical locations among the native populations. Two nuclear genes (arginine kinase and carbamoyl-phosphate synthetase 2-aspartate transcarbamylase-dihydroorotase) were more conservative, and intraspecific differences were lower than interspecific differences. The mitochondrial genetic variation was probably caused by evolution of lineages among geographically isolated populations. But it is immature to infer the existence of cryptic species based on cytochrome c oxidase I differences. All samples collected from poplar populations were indigenous and formed close relationship with a specimen from eastern and southern China. Surprisingly, pests from poplar populations in Jiangsu and Shanghai showed different haplotypes and mutualists. This suggested that the control strategies should consider the genetic and mutualistic diversity of beetles at different poplar localities.

Pervasive heteroplasmy in an invasive ambrosia beetle (Scolytinae) in southern California.

Heteroplasmy, the presence of multiple mitochondrial genotypes (mitotypes) within an individual, has long been thought to be a rare aberrance that is quickly removed by selection or drift. However, heteroplasmy is being reported in natural populations of eukaryotes with increasing frequency, in part due to improved diagnostic methods. Here, we report a seemingly stable heteroplasmic state in California populations of the polyphagous shothole borer (PSHB), Euwallacea fornicatus; an invasive ambrosia beetle that is causing significant tree dieback. We develop and validate a qPCR assay utilizing locked nucleic acid probes to detect different mitotypes, and qualitatively assess heteroplasmy in individual PSHB. We prove the utility of this assay by: (1) mitotyping field-collected PSHB, documenting the prevalence of heteroplasmy across its range in California; and, (2) measuring relative titers of each mitotype across multiple generations of heteroplasmic laboratory colonies to assess the stability of transmission through the maternal germline. We show that our findings are unlikely to be explained by the existence of NUMTs by next generation sequencing of contiguous sections of mitochondrial DNA, where each of the observed heteroplasmic sites are found within fully functional coding regions of mtDNA. Subsequently, we find heteroplasmic individuals are common in Californian field populations, and that heteroplasmy persists for at least 10 generations in experimental colonies. We also looked for evidence of the common occurrence of paternal leakage, but found none. In light of our results, we discuss competing hypotheses as to how heteroplasmy may have arisen, and continues to perpetuate, in Californian PSHB populations.

Pest categorisation of non-EU Scolytinae on non-coniferous hosts.

The EFSA Panel on Plant Health performed a group pest categorisation for the EU territory of non-EU Scolytinae (Coleoptera: Curculionidae) on non-coniferous hosts, which total 6495 known species. Most species attack apparently healthy, weakened or dead trees, either feeding on the phloem ('bark beetles' subgroup) or on fungi inoculated into the sapwood ('ambrosia beetles' subgroup). Smaller subgroups feed and reproduce in seeds and fruits, or in herbaceous plants. Some species are polygynous, the males initiate a gallery or a chamber on or in a new host and attract females. Others are monogamous, and the females initiate the new galleries. Many species respond to primary volatile attractants emitted by the hosts, and some produce aggregation pheromones that attract conspecifics of both sexes. The species attacking living hosts are often associated with fungi that contribute to weakening the host defences and provide nutrients to the insects. Some are inbreeding; the males in the offspring mate with their sisters and rarely leave their natal tree. The larvae of all species develop and pupate within their hosts. Based on catalogues and other published data, a database was constructed providing information on hosts, feeding and reproductive habits, geographic distribution and the Köppen-Geiger climate types in countries where species occur. The Scolytinae were screened to exclude species in the following categories: (i) 708 species attacking conifers; (ii) 127 species present in at least four EU Member States and (iii) 440 species occurring in areas with climatic conditions not occurring in the EU. Among the remaining 5220 species, 88 species known for their mobility, occupying at least two landmasses separated by geographical barriers and some of which had impact levels documented in literature, were extracted. They were grouped into four subcategories: (i) 12 species with high impact on plant health; (ii) 16 species with low or doubtful impact; (iii) 48 species with no impact; (iv) 12 species with no impact and which had never been recorded as 'introduced' in the consulted catalogues but occurring on at least two landmasses. All 88 species could enter the EU with wood or wood products, or with plants for planting, and could establish because host plants are available, and climate is suitable in parts of the EU. Control measures to inhibit introduction are available. There is considerable uncertainty regarding the potential impact of many species. Methods for the reliable identification of many species are lacking. For some species of non-EU Scolytinae on non-coniferous hosts, all criteria assessed by EFSA for consideration as potential quarantine pest are met. Nevertheless, the Panel was not able to develop a method to discriminate confidently between species that clearly meet the criteria for potential quarantine pest status and those that do not.

Tradeoffs in longleaf pine conservation: Prescribed fire management increases exotic ambrosia beetle abundance in pine-hardwood forests

Exotic woodboring insects, including some ambrosia beetles (Coleoptera: Curculionidae, Scolytinae, and Platypodidae), are threatening native forests worldwide. Longleaf pine (Pinus palustris Mill.) forest is an endangered habitat in the southeastern United States. One of the most important actions necessary for its conservation is prescribed fire, which maintains its savanna structure. However, prescribed fire is a forest disturbance, possibly creating new niches for colonization by exotic insects. The interaction between prescribed fire and exotic ambrosia species is understudied, especially in highly fire-dependent ecosystems. We carried out a two-year experiment in mixed longleaf pine forests in Alabama, USA. We compared ambrosia beetle communities in recently burned and unburned sites. We found that more than 66 % of total individuals in longleaf pine forests, regardless of fire management, were exotic species. Moreover, exotic ambrosia beetles were more abundant in burned stands, whereas native species showed no difference between burned or unburned stands. Fire management influenced stand species composition for native but not exotic ambrosia beetles. These results indicate that trade-offs exist in managing fire-dependent ecosystems, especially in the Anthropocene era, which is associated with rampant biological invasions. Fire is important to preserve the longleaf pine habitat, but it simultaneously acts as a disturbance, increasing the population density of those exotic species taking advantage of the presence of stressed or dying trees.

Unravelling transcriptional responses of the willow to Fusarium kuroshium infection

Fusarium kuroshium and the ambrosia beetle Euwallacea kuroshio attack several tree species, including the arroyo willow (Salix lasiolepis). Despite the importance of this pest, there is no molecular information about this plant-fungus interaction. Using an in vitro pathosystem of S. lasiolepis leaves – F. kurosihum and the RNA-seq approach, this study analyzed for the first time the transcriptome of both organisms at 4-, 8-, and 12-days post-inoculation. De novo assembly was done to generate the willow transcriptome, and a total of 361,2151 unique transcripts (UniGenes) were found. 4,583 UniGenes responded to the infection, and the posterior analysis showed that it contains the molecular elements to develop both pattern- and effector-triggered immunity responses (PTI and ETI, respectively). Significant expression changes of genes involved in an oxidative burst, Ca2+ signaling, and mutually antagonistic interaction between salicylic acid- and jasmonic acid/ethylene-dependent signaling suggest that the willow recognized the fungus and triggered downstream responses. Additionally, chromatin remodelers and non-coding RNA play a significant role in plant defense. Concerning F. kuroshium, 178 induced genes that show homology with genes involved in the pathogenicity in other ascomycetes fungi plus transport proteins, ribosomal proteins, and uncharacterized proteins with specific domains were identified. Collectively these data provide a basis for future research on the molecular response of this transcendental tree during biotic stress, specifically during Fusarium dieback disease.

Trap captures of invasive ambrosia beetles (Coleoptera: Curculionidae) as influenced by ethanol release rate

Abstract 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.

Few chemoreceptor genes in the ambrosia beetle Trypodendron lineatum may reflect its specialized ecology

BackgroundChemoreception is crucial for insect fitness, underlying for instance food-, host-, and mate finding. Chemicals in the environment are detected by receptors from three divergent gene families: odorant receptors (ORs), gustatory receptors (GRs), and ionotropic receptors (IRs). However, how the chemoreceptor gene families evolve in parallel with ecological specializations remains poorly understood, especially in the order Coleoptera. Hence, we sequenced the genome and annotated the chemoreceptor genes of the specialised ambrosia beetle Trypodendron lineatum (Coleoptera, Curculionidae, Scolytinae) and compared its chemoreceptor gene repertoires with those of other scolytines with different ecological adaptations, as well as a polyphagous cerambycid species.ResultsWe identified 67 ORs, 38 GRs, and 44 IRs in T. lineatum (‘Tlin’). Across gene families, T. lineatum has fewer chemoreceptors compared to related scolytines, the coffee berry borer Hypothenemus hampei and the mountain pine beetle Dendroctonus ponderosae, and clearly fewer receptors than the polyphagous cerambycid Anoplophora glabripennis. The comparatively low number of chemoreceptors is largely explained by the scarcity of large receptor lineage radiations, especially among the bitter taste GRs and the ‘divergent’ IRs, and the absence of alternatively spliced GR genes. Only one non-fructose sugar receptor was found, suggesting several sugar receptors have been lost. Also, we found no orthologue in the ‘GR215 clade’, which is widely conserved across Coleoptera. Two TlinORs are orthologous to ORs that are functionally conserved across curculionids, responding to 2-phenylethanol (2-PE) and green leaf volatiles (GLVs), respectively.ConclusionsTrypodendron lineatum reproduces inside the xylem of decaying conifers where it feeds on its obligate fungal mutualist Phialophoropsis ferruginea. Like previous studies, our results suggest that stenophagy correlates with small chemoreceptor numbers in wood-boring beetles; indeed, the few GRs may be due to its restricted fungal diet. The presence of TlinORs orthologous to those detecting 2-PE and GLVs in other species suggests these compounds are important for T. lineatum. Future functional studies should test this prediction, and chemoreceptor annotations should be conducted on additional ambrosia beetle species to investigate whether few chemoreceptors is a general trait in this specialized group of beetles.

Emerging pest threats to Litsea deccanensis gamble: implications for conservation and management in the Western Ghats, India

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.

Comparison of ethanol-baited trap designs for ambrosia beetles in orchards in the eastern United States.

Ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are among the most devastating pests of orchards, nurseries, and forests. Improving trap design and ethanol lures for capturing ambrosia beetles is necessary to develop effective monitoring and management strategies. In this 2-year study, we assessed 4 trap designs and 3 commercially formulated ethanol lures to refine trapping methods tailored for orchard environments in the eastern United States. Our investigation included orchards in 2 regions, Georgia (pecan orchards) and New York (apple orchards), targeting major ambrosia beetle (Coleoptera: Curculionidae) pest species such as Xylosandrus crassiusculus (Motschulsky), X. compactus (Eichhoff), X. germanus (Blandford), and Anisandrus maiche (Stark). Among the trap designs evaluated, clear sticky cards were most effective for capturing ambrosia beetles across orchard locations. Notably, in Georgia, sticky cards paired with specific low-release ethanol lures demonstrated enhanced capture of X. crassiusculus and X. compactus, 2 key ambrosia beetle pests found infesting young pecan trees. Similarly, in New York, sticky cards baited with low-release ethanol lures captured the highest rates of X. germanus and A. maiche, thus indicating its suitability for diverse ambrosia beetle populations. Overall, our study provides practical implications for tailoring trapping protocols to optimize ambrosia beetle management strategies in orchard settings.

Fungi associated with ambrosia beetle Xylosandrus germanus in Slovakia

The black timber bark beetle (Xylosandrus germanus) is a strongly invasive ambrosia beetle and an important forest pest in Slovakia. This pest is closely associated with symbiotic fungi used as its food source. We investigated the fungi associated with X. germanus adults in Slovakia. In this study, Beauveria bassiana, B. pseudobassiana, Clonostachys rosea, Fusarium oxysporum, Ophiostoma quercus, Phaeoacremonium scolyti, and Talaromyces amestolkiae were isolated and identified by morphological and molecular analyses. The fungus Ophiostoma quercus was most frequently isolated from living beetles, while the entomopathogenic Beauveria bassiana was the most commonly isolated from dead beetles. The morphological descriptions of fungi based on isolates from the surface of X. germanus adults are provided.

Integrative taxonomy sheds light on species boundaries and relationships in the inbred haplodiploid ambrosia beetle genus Xyleborus

Abstract 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.

Influence of Ethanol Grade on Captures of Ambrosia Beetles in Tree Fruit Orchards, Ornamental Nurseries, and Lumber Yards.

Ambrosia beetles, particularly invasive species within the tribe Xyleborini, such as Xylosandrus germanus (Blandford, 1894), pose significant threats to various ecosystems and managed habitats worldwide. Monitoring these invaders is vital for effective pest management, typically accomplished through ethanol-baited traps. We compared trap efficacy using denatured ethanol versus absolute ethanol in orchards, tree nurseries, and lumber yards in northeastern Ohio, USA, finding that absolute ethanol traps captured significantly more X. germanus. Analysis revealed acetone, ethanol, and methyl isobutyl ketone in the denatured ethanol, likely impacting trap efficacy. Our study underscores the importance of using pure denatured ethanol without acetone for effective monitoring, especially for X. germanus. Exotic xyleborines dominated trap captures across various habitats, emphasizing the need for tailored pest management strategies. Further research is warranted to explore the chemical ecology of ambrosia beetles and the influence of ethanol impurities on trap effectiveness.

Euwallacea perbrevis (Schedl, 1951) and associated novel fungal symbiont, Fusarium sp.: A potential cause of wilting in cocoa, Theobroma cacao in India

Cocoa is a commercially important beverage crop that faces new challenges in the context of climate change, which can alter pest and disease dynamics in cocoa plantations. In the Dakshina Kannada district of Karnataka, India, an abrupt increase in cocoa wilt was observed during the 2017–18 and 2018–19 seasons. Systematic examination of affected trees revealed consistent attacks of Euwallacea perbrevis (Schedl, 1951; Coleoptera: Curculionidae: Scolytinae). In-depth studies of the wilted trees revealed the association of the plant pathogenic fungus Fusarium sp. with Euwallacea perbrevis. The identity of the obtained pure culture from the insect and infected tree was confirmed as Fusarium sp. using amplification of ribosomal DNA, RNA polymerase II largest subunit (RPB1) and translation elongation factor 1 (Tef1) genes. Notably, this study reports a remarkable case of mutualistic association between ambrosia beetles and Fusarium sp., belonging to the Fusarium solani species complex (FSSC), rather than the Ambrosia Fusariumclade (AFC). This finding highlights the intriguing diversity of mutualistic relationships in nature and sheds new light on the complex interactions between organisms. The present study also investigated the impact of rainfall on the colonization and spread of the Euwallacea-Fusarium complex. The findings revealed that rainfall was identified as a predisposing factor for the incidence and spread of attacks. Additionally, the study conducted a comprehensive analysis of the modeling of Euwallacea-Fusarium complex spread over a specific period of time.

The Redbay Ambrosia Beetle and Laurel Wilt

The redbay ambrosia beetle, harmless in its native Asia, has become a formidable pest since its introduction to the United States in 2002. The beetle spreads the fungus Harringtonia lauricola, a lethal pathogen of North American Lauraceae trees, including avocados. The fungus infection triggers a rapid onset of laurel wilt disease, which has nearly eliminated laurel trees across the southeastern United States within a few years. The beetle has spread across nearly 300 counties in the Southeast, facilitated by trade in wood products. Effective control in natural environments remains an unresolved challenge; in avocado groves, infected trees must be removed and destroyed. Introduction of X. glabratus into Mexico, California, Central America, or South America, regions with substantial avocado industries and diverse native Lauraceae species, would be disastrous. International cooperation is necessary to address this threat.