Megaplatypus mutatus (syn. Platypus sulcatus) is an ambrosia beetle native to South America, which represents the main forest pest in Argentina of Poplar plantations and is also an emerging pest in Europe, representing a potential risk to forest and fruit plantations globally due to its low specificity. Knowledge of the interactions this insect has with microbes will be important in understanding its impacts and management. In this study, we characterized the fungal diversity associated with M. mutatus in Populus trees in Argentina. The fungal community of 28 attacked trees was studied by evaluating 1104 gallery fragments and 110 fragments of insects. Fungal isolates were identified using morphology and phylogenetic analysis of the internal transcribed spacer region of nDNA. Nineteen taxa were identified, the most relevant Fusarium solani species complex, three species of Raffaelea and Graphium basitruncatum. Despite the lower frequency occurred by Raffaelea spp. and G. basitruncatum, we detected a specificity between male/female and location in the gallery. Additionally, the topology of the galleries is described based on analyses with computed tomography and nuclear magnetic resonance. Enhancing these techniques, an image combining both data was produced, suggesting that the water circulation across outer sections might be involved in the modulation of the gallery topology.

We report the presence of the invasive ambrosia beetle, Euwallacea fornicatus (Eichhoff, 1868), for the first time in South America. The identity is established by morphological and molecular methods, although the sequences suggest that it represents a separate haplotype from the populations that have caused significant damage in South Africa, Israel, and California, and is most phylogenetically similar to specimens from Asia and greenhouses in Europe. This pest is one of the most successful invaders, causing high economic and ecological impacts in the regions where it is introduced. Our records are from the city of Buenos Aires, Argentina, one of the most populated and largest port cities in South America, where attacks by this beetle are present on a wide range of living street trees. The large number of trees attacked and the new records of reproductive host species suggest that the beetle is already established and widespread in the city’s urban forest. This context implies that the beetle may pose a threat to the urban and natural environment, as well as to the forests and fruit production of the region. Informamos la presencia del escarabajo invasor de ambrosía, Euwallacea fornicatus (Eichhoff, 1868), por primera vez en Sudamérica. La identificación se estableció mediante métodos morfológicos y moleculares, si bien las secuencias sugieren que representa un haplotipo distinto de las poblaciones que han causado daños significativos en Sudáfrica, Israel y California, resulta filogenéticamente más similar a especímenes de Asia e invernaderos de Europa. Esta plaga es una de las especies invasoras más exitosas, causando altos impactos económicos y ecológicos en las regiones donde es introducida. Nuestros registros provienen de la ciudad de Buenos Aires, Argentina, una de las ciudades portuarias más pobladas y grandes de Sudamérica, donde los ataques de este coleóptero están presentes en una amplia diversidad de especies pertenecientes al arbolado urbano. El gran número de árboles atacados y los nuevos registros de especies hospedadoras reproductoras sugieren que el coleóptero ya está establecido y extendido en el bosque urbano de la ciudad. Este contexto implica que el coleóptero puede suponer una amenaza para el medio urbano y natural, así como para los bosques y la producción frutícola de la región.

We provide scientists and decision-makers with up-to-date information on Megaplatypus mutatus (Coleoptera: Curculionidae: Platypodinae), a forest insect native to South America that has invaded other regions. Emphasis is given to information that may prove relevant for the development of early detection, containment and management programs and improved risk analyses. The increase in global movement of people and goods, coupled with expected climatic scenarios, suggests that M. mutatus may arrive and establish populations in new areas. The major impact of this forest pest has always been reported in exotic tree species, even within its native range. The absence of a coevolutionary history with ‘naïve’ host trees is a relevant factor when analyzing and understanding the magnitude of the problem posed by this beetle and fungi associated with it. Notably, among preferred hosts are the widely planted Eucalyptus and Populus spp., facilitating the invasion of this insect into new regions and posing a threat to commercial forestry.