Several species of the genus Heracleum (Umbelliferae) were introduced into Europe from south‐west Asia in the 19th century and are now widespread in many countries. At least three invasive taxa with unresolved relationships to one another are thought to occur in Europe: Heracleum mantegazzianum Sommier & Levier, H. sosnowskyi Manden, and H. persicum Desf. ex Fischer. They are tall plants forming extensive stands with a high cover. To elucidate genetic relationships between the species, and gain insight into their invasion history, samples were collected from native ranges in Asia and invaded ranges of the three species in Europe and analysed using amplified fragment length polymorphism. Five other Heracleum species were also studied and in total, 189 samples from 72 populations were analysed. The results confirmed that there are three distinct tall Heracleum species invading in Europe. Within each of the three species, plants collected in the invaded range are genetically close to those from their native ranges. A close genetic relationship between the three invasive Heracleum species in Europe was also found. A high overall genetic variability detected in the invaded range suggests that the majority of invading populations were not affected by a genetic bottleneck and that rapid evolution, drift, or hybridization played a role in genetic structuring of invading populations. For H. mantegazzianum, genetic distance of populations in the native range significantly decreased with geographical distance, but not in the invaded range. It is likely that the current pattern of genetic diversity in Europe resulted from multiple introductions of all three species.

No abstract

Comparative field studies on the management of fire blight were conducted in California on Asian and Bartlett pear using single-bactericide, mixture, and rotation treatments of selected compounds. Treatment efficacy was evaluated based on the natural occurrence of the disease or after inoculation with Erwinia amylovora. Kasugamycin at 100 mg/liter demonstrated similar or higher pre- and post-infection activity than the industry standards, streptomycin and oxytetracycline. Phytotoxicity caused by kasugamycin was observed only when five or six sequential weekly applications were done. In a six-spray rotation program including three bactericides (copper, kasugamycin, and oxytetracycline), with each being used twice, phytotoxicity was minor. Baseline sensitivity concentrations for kasugamycin were established for growth of 376 isolates of E. amylovora from California. Values for the lowest concentration where a reduction in growth on nutrient agar was observed ranged from 3.5 to 18.3 mg/liter, with a mean value of 8.7 mg/liter. Values for ≥95% inhibition of growth ranged from 6.9 to 46.7 mg/liter, with a mean value of 18.5 mg/liter. These inhibitory values for kasugamycin were higher than those for streptomycin or oxytetracycline. The in vitro activity of all three compounds was highly dependent on the agar medium used in the sensitivity assay. The activity of kasugamycin was also highly dependent on the pH of the medium and was significantly higher at pH 5.1 than pH 7.3. With the planned registration in the United States, kasugamycin represents the first new, highly effective bactericide for managing fire blight in over 40 years.

Fallopia japonica (Japanese knotweed) is a well-known invasive alien species in the UK and elsewhere in Europe and North America. The plant is known to have a negative impact on local biodiversity, flood risk and ecosystem services; but in the UK it is also considered to pose a significant risk to the structural integrity of buildings that are within seven m of the above ground portions of the plant. This has led to the presence of the plant on residential properties regularly being used to refuse mortgage applications. Despite the significant socioeconomic impacts of such automatic mortgage option restriction, little research has been conducted to investigate this issue. The ‘seven-m rule’ is derived from widely adopted government guidance in the UK. This study considered if there is evidence to support this phenomenon in the literature, reports the findings of a survey of invasive species control contractors and property surveyors to determine if field observations support these assertions, and reports a case study of 68 properties, located on three streets in northern England where F. japonica was recorded. Additionally, given the importance of proximity, the seven-m rule is also tested based on data collected during the excavation based removal of F. japonica from 81 sites. No support was found to suggest that F. japonica causes significant damage to built structures, even when it is growing in close proximity to them and certainly no more damage than other plant species that are not subject to such stringent lending policies. It was found that the seven-m rule is not a statistically robust tool for estimating likely rhizome extension. F. japonica rhizome rarely extends more than four m from above ground plants and is typically found within two m for small stands and 2.5 m for large stands. Based on these findings, the practice of automatically restricting mortgage options for home buyers when F. japonica is present, is not commensurate with the risk.

During the first 25 years, EMAPi conferences were attended by 1280 participants from 77 countries in five continents and produced 1474 presentations, including 44 keynotes on a broad range of aspects of plant invasion ecology. The series was established in Loughborough, UK, in 1992 and with its 14th conference in Lisbon, Portugal in 2017 it has become the longest held series of regular meetings in plant invasion ecology with the number of participants in the last decade ranging between 150 and 250 per meeting. Of the 14 events so far, eight were held in Europe, three in North America and the remaining three in Australia, Africa and South America, respectively. The EMAPi series continues to be maintained by an informal board consisting of the organizers of previous meetings. Over time, there has been a shift in research focus from the ecology of species invasiveness and community invasibility, analyses of distribution and spread dynamics towards presentations dealing with management, control, risk assessment and impact. The latter topics, although well represented even at the beginning of the EMAPi conferences, increased their proportion among the total number of papers delivered, from about a quarter to more than half. Ten conferences yielded proceedings and up to 2008 these were published as books with Electronic supplementary material The online version of this article (

The Midlands Region of the Environment Agency has developed a management system, in the form of an Environmental Action Plan (EAP) to ensure that the constraints and mitigation measures identified in the Environmental Statement document are delivered on the ground. The reasons are considered for developing such procedures and examples are provided of the environmentalobjectives and targets which lie at the heart of the new procedures. The EAP is designed to provide a summary of the environmental constraints, adverse effects and their associated mitigation measures, and monitoring requirements, in an easily accessible document for both technical and non-technical readers.

No abstract

Fallopia japonica (Japanese knotweed) is a well-known invasive alien species in the United Kingdom and elsewhere in Europe and North America. The plant is known to have a negative impact on local biodiversity, flood risk, and ecosystem services; but in the UK it is also considered to pose a significant risk to the structural integrity of buildings that are within 7 m of the above ground portions of the plant. This has led to the presence of the plant regularly being used to refuse mortgage applications. Despite the significant socioeconomic impacts of such automatic mortgage option restriction, little research has been conducted to investigate this issue. The ‘7 m rule’ is derived from widely adopted government guidance in the UK. This study considered if there is evidence to support this phenomenon in the literature, reports the findings of a survey of invasive species control contractors and property surveyors to determine if field observations support these assertions, and reports a case study of 68 properties, located on three streets in northern England where F. japonicawas recorded. Additionally, given the importance of proximity, the 7 m rule is also tested based on data collected during the excavation based removal of F. japonicafrom 81 sites. No support was found to suggest that F. japonicacauses significant damage to built structures, even when it is growing in close proximity to them and certainly no more damage than other plant species that are not subject to such stringent lending policies. It was found that the 7 m rule is not a statistically robust tool for estimating likely rhizome extension. F. japonica rhizome rarely extends more than 4 m from above ground plants and is typically found within 2 m for small stands and 2.5 m for large stands. Based on these findings, the practice of automatically restricting mortgage options for home buyers when F. japonicais present, is not commensurate with the risk.