Common mistletoe is increasingly mentioned as contributing not only to the decline of deciduous trees at roadside and in city parks, but to conifers in stands. The presence of Viscum in fir stands has been known for many years, but since 2015 has also been the cause of damage to pine. In 2019, mistletoe was observed on 77.5 thousand hectares of Scots pine stands in southern and central Poland. Drought resulting from global climate change is implicated as an important factor conducive to weakening trees and making them more susceptible to the spread of mistletoe and other pests. This paper presents an overview of the latest information on the development of this semi-parasitic plant in Poland, its impact on tree breeding traits and raw material losses, as well as current options for its prevention and eradication.

Monochamus sartor sartor from Central European mountain ranges and M. s. urussovii from the Eurasian boreal zone are subspecies whose taxonomic statuses have been questioned. This sawyer beetle is a natural element of spruce forests but is considered to be a timber pest in spruce plantations. In this study, different sets of data (morphology, genetics and ecology) were used to verify the taxonomic status of M. sartor across its entire range. Morphologically, not only both subspecies but also European and Asian populations of M. s. urussovii were found to be distinct. Genetic data also showed that both subspecies have distinct mitochondrial haplogroups; however, divergence between them is very weak (of ca. 1%), suggesting they split very recently, possibly at the end of the Pleistocene glaciations. Species delimitation methods gave discordant results, either rejecting the species status of M. s. sartor and M. s. urussovii (Poisson tree processes) or confirming them as distinct taxa (the multispecies coalescent model for species validation). Host plant preferences also partially differentiate the subspecies, as M. s. urussovii has a broader diet than the generally monophagous, spruce-dependent M. s. sartor. Moreover, each subspecies is infected by different strains of the intracellular bacterium Wolbachia, which could be one of the factors causing their genetic isolation, regardless of geographic isolation. Aside from broadening the basic knowledge on the taxonomy and genetics of Monochamus sartor, this study shows that any research on these sawyers needs to consider their separate phylogenetic lineages, as do any plans for population management or conservation.

Forests are important habitats that harbor high biodiversity and have great economic value to humans. These ecosystems depend on saproxylic organisms, which play a crucial role in the decomposition of the main substrate of forests – wood. The highly important group of saproxylic organisms are beetles, with numerous species that are either of conservation concern (rare and threatened) or have economic value (“pests”). This review summarizes what is known about intra- and interspecific genetic information on species or populations of saproxylic beetles. A search of the literature yielded 110 articles published in 57 journals. The majority of molecular research has focused on “pests” (82 articles on 59 species), with fewer studies of the “non-pest” beetles (28 articles on 40 species, including 10 relicts of primeval forests). Most studies concerned Palearctic and Nearctic taxa, with only a few articles on beetles from (sub)tropical forests. Members of 11 families, 38 genera and 99 species were the subject of molecular studies. The majority of studies (71%) were conducted on beetles associated with conifers. Genetic metrics were found to have different overall values in “pests” and the “non-pest” species. Analyzes resulted in identification of units or either conservation (15 cases) or taxonomic (33) value, the discovery of hybridization (4), invasion routes, and common phylogeographic patterns with the localization of glacial refugial areas. This article is the first comprehensive summary of what is known about the history, present-day diversity, and relationships of highly important group of saproxylic beetles based on molecular studies. “Pests” found to be much wider studied than threatened taxa. A list of species that should be the subject of future molecular studies was provided along with a rationale. Finally, methodological and objective deficiencies in previous studies were characterized.