This is potentially a game-changer when it comes to dealing with #Knotweed (which just laughs at #Glyphosate)!

#MeshTech: A New Strategy for Managing Knotweed

February 24, 2026

"Knotweed (#Reynoutria spp.) is a severely invasive plant originating from Eastern Asia. Introduced to the East Coast in the late 1800s as an ornamental, knotweed has since become ubiquitous across North America, reaching over 40 US states and 8 Canadian provinces. Knotweed has proven extremely detrimental to a wide variety of ecosystems in which it has established. Forming tall, dense thickets, knotweed shades out native plants, preventing them from growing. Additionally, knotweed is #allelopathic, meaning it releases organic compounds into the soil that inhibits the growth of native plant species.

Knotweed also increases erosion along streams and riverbanks. By shading out native groundcover species and reducing the diverse root reinforcement provided by native species in riparian zones, riverbanks lose considerably more soil when infested with stands of knotweed (Hammer 2019, Matte et al. 2021). This erosion can increase turbidity of waterways, potentially affecting fish and other aquatic species (Henley et al. 2000). The reduction of native plants in riparian zones paired with winter dieback of knotweed stems also leaves riverbanks extremely vulnerable to winter and early spring flooding. This degradation of the riparian area creates a feedback loop in which floods carry knotweed propagules downstream, where they can colonize and increase erosion in new areas (Colleran et al. 2020).

Historically, management of knotweed has been extremely time-and-resource intensive. Large populations require years of consistent treatment, often combining mechanical and chemical approaches to be effective. This commitment to diligent, multi-year mechanical treatment can be discouraging and can lead many to abandon treatment plans before completion. However, a new knotweed management technique could reduce labor inputs.

Developed by Dr. Eric Donnelly, the MeshTech management technique has produced promising results at managing the growth and spread of knotweed while dramatically reducing labor inputs. This method involves cutting knotweed stems down to the soil level and laying -inch galvanized steel hardware fencing over the cut stems. When knotweed resprouts, it grows through the openings in the fencing. As stems mature and thicken, the metal fencing will begin to cut into the stems.

The knotweed will continue to grow through the fencing, effectively girdling itself at its base. This method aims to impact knotweed's nutrient pathways while also damaging the structural integrity of the plant. Alone, this method cannot eradicate knotweed populations. However, the MeshTech method can potentially reduce the health and vigor of knotweed, thus reducing the amount of cutting required in a growing season and the rate of spread in an area.

At the #PleasantHillPreserve in #ScarboroughME, the #ScarboroughLandTrust (#SLT) has begun implementing the MeshTech method to manage a portion of their knotweed infestation. An effort led by SLTs #Stewardship Director Sami Wolf and Nathan Hjort, owner of Absolutely Complete Property Services, initial results indicate that the hardware fencing is proving successful. The knotweed forced to grow through the hardware fencing at Pleasant Hill Preserve showed clear signs of strain. Stems demonstrated significantly stunted growth and had even begun flowering early, an indication that a plant is under stress. While knotweed struggled to grow through the -inch holes, #NativeFlora had begun to sprout up through the hardware fencing. Other knotweed management practices, such as #tarping or mowing, often discourage the growth of native species in a management area. Over time, the presence of native flora could provide an extra level of #BioticResistance that could help slow the growth of knotweed and help kickstart #NativeRevegetation efforts. Eventually, supplemental plantings of native woody species can take place by cutting openings in the fence to allow for these larger species to grow. The fence can also be easily staked down, preventing knotweed or moving water from moving it out of place.

It is important to note that knotweed is a resilient plant and there is no single management action alone that will completely eliminate a population. The most effective knotweed management strategies use creative combinations of multiple approaches. Knotweed is a rhizomatous species, meaning it has an extensive, underground nutrient storage system made up of horizontal rhizomes that store nutrients. Draining this underground nutrient storage is the key to effectively managing an infestation. Consistent cutting of knotweed forces the plant to exhaust its below ground resources. By combining a cutting regimen with the MeshTech method, land managers could potentially see a significant reduction in their management timeline.

The effectiveness of this method provides promising implications for the future of knotweed management in Maine. Paired with consistent management, the MeshTech method could provide Maine with another tool to mitigate the spread of knotweed and reduce our reliance on chemical treatments."

Source:
https://www.maine.gov/dacf/about/news/news.shtml?id=13343931

#SolarPunkSunday #NaturalSolutions #NoHerbicides #HerbicideAlternatives #JapaneseKnotweed #LandTrusts #Rewilding #NativePlantSpecies #RestoringNativePlantSpecies #InvasiveSpecies #InvasiveSpeciesWeek
#MaineDepartmentOfAgricultureConservationAndForestry

News: Newsroom: Maine Department of Agriculture, Conservation and Forestry

Genetic Polymorphism of Invasive Species of Knotweed (Reynoutria) Assessed by the matK and rpl32-trnL (UAG) Regions of Chloroplast DNA

Genetic Polymorphism of Invasive Species of Knotweed... ##bioinformaticanalysis ##chloroplastdna ##geneticpolymorphism ##molecularevolution ##moleculargenomics ##bioinformatics ##chloroplasts ##plastome ##molecularphylogeny ##genomics ##knotweed ##reynoutria ##matk ##rpl32trnl

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Genetic Polymorphism of Invasive Species of Knotweed (Reynoutria) Assessed by the matK and rpl32-trnL (UAG) Regions of Chloroplast DNA - Cytology and Genetics

Abstract An important model system for studying the role of genetic diversity and hybridization in plant invasions is the species complex of the genus Reynoutria Houtt. Within the secondary distribution range, two species of this genus are widespread, R. japonica Houtt. and R. sachalinensis (F. Schmidt) Nakai, as well as their derivatives, the hexaploid R. × bohemica Chrtek & Chrtková and the tetraploid R. × moravica (Hodálová and Mereďa) Olshanskyi and Antonenko, which are recognized as separate species. The genetic diversity of the species of the genus Reynoutria in Ukraine is still almost unexplored by molecular methods. In this work, we determined chloroplast haplotypes for samples of R. japonica, R. sachalinensis and R. × bohemica from Ukraine and other European countries and compared them with haplotypes of Reynoutria from the primary distribution range in China and Korea. The genetic diversity of R. japonica from the primary distribution range was significantly higher compared to European samples, which are mainly represented by the haplotype J1.1. At the same time, we identified haplotypes J1.2 and J1.3 specific to the Eastern European area, which probably arose as a consequence of the divergence of the chloroplast genome within the secondary distribution range. Of the five samples morphologically identified as R. × bohemica, three carry the haplotype J1.1, which is consistent with the idea that R. japonica var. japonica was involved as a maternal form in the formation of R. × bohemica. However, a chloroplast haplotype identical to R. sachalinensis was detected in two samples from the Alpine region of Europe. These samples likely represent another hybrid species of R. × moravica. Therefore, the use of chloroplast DNA markers is crucial for identifying the donor of maternal subgenomes in hybrid forms of the genus Reynoutria.

SpringerLink
Intragenomic Polymorphism of the ITS1-5.8S-ITS2 Region in Invasive Species of the Genus Reynoutria - Cytology and Genetics

Abstract The ITS1-5.8S-ITS2 (ITS1-2) region of the 35S rDNA is widely used for molecular barcoding and in the phylogenetics of plants. It is believed that, due to concerted evolution, all copies of 35S rDNA in eukaryotic genomes should be effectively homogenized. However, the existence of intragenomic polymorphism of the ITS1-2 region in plant genomes has recently been demonstrated, which may be a consequence of hybridization within or between species. In this study, the intragenomic polymorphism of the ITS1-2 region was evaluated using Illumina amplicon sequencing in accessions of two invasive species of the genus Reynoutria, R. japonica and R. sachalinensis, from Ukraine and Romania. Hybridization between these species can lead to the emergence of more aggressive invasive forms. The ITS1-2 sequences of the species studied were found to be represented by some major and minor subclasses/variants, indicating their incomplete homogenization. The number of major variants range from two in R. japonica to six in R. sachalinensis. The ITS1-2 variants that are widespread in the genome of one species may be present at low levels in another species, indicating possible interspecies hybridization. The obtained results show that the ITS1-2 intragenomic polymorphism must be taken into account when performing barcoding, reconstructing the phylogeny of low-level taxa, and for the identification of hybrid forms.

SpringerLink