Rapid growth and early flowering in an invasive plant, purple loosestrife (Lythrum salicaria L.) during an El Ni�o spring

The potential use of herbarium specimens to detect herbivory trends is enormous but largely untapped. The objective of this study was to reconstruct the long-term herbivory pressure on the Eurasian invasive plant, purple loosestrife ( Lythrum salicaria ), by evaluating leaf damage over 1323 specimens from southern Québec (Canada). The hypothesis tested is that that the prevalence of herbivory damage on purple loosestrife is low during the invasion phase and increases throughout the saturation phase. Historical trends suggest a gradual increase in hole feeding and margin feeding damage from 1883 to around 1940, followed by a period of relative stability. The percentage of specimens with window feeding damage did not begin to increase until the end of the twentieth century, from 3% (2–6%) in 1990 to 45% (14–81%) in 2015. Temporal changes in the frequency of window feeding damage support the hypothesis of an increasing herbivory pressure by recently introduced insects. This study shows that leaf damage made by insects introduced for the biocontrol of purple loosestrife, such as coleopterans of the Neogalerucella genus, can be assessed from voucher specimens. Herbaria are a rich source in information that can be used to answer questions related to plant-insect interactions in the context of biological invasions and biodiversity changes. This article is part of the theme issue ‘Biological collections for understanding biodiversity in the Anthropocene’.

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Predicting the Spread of Purple Loosestrife (Lythrum salicaria) in the Prairies

The Canadian Field-Naturalist ◽

10.22621/cfn.v126i4.1376 ◽

2013 ◽

Vol 126 (4) ◽

pp. 306 ◽

Cited By ~ 3

Author(s):

Cory J. Lindgren ◽

David Walker

Keyword(s):

Potential Distribution ◽

Invasive Plant ◽

Lythrum Salicaria ◽

Training Data ◽

Purple Loosestrife ◽

Full Potential ◽

Ecological Niche Models ◽

Predictive Variables ◽

Modelling Techniques ◽

And Training

Purple Loosestrife (Lythrum salicaria) is an invasive plant introduced into North America in the early 1800s. It has since spread into the prairie provinces of Canada (Manitoba, Saskatchewan, and Alberta). It invades wetland habitats, marshes, riparian areas, and natural areas, and it outcompetes native wetland vegetation. In this study we modelled the potential distribution of Purple Loosestrife in the Prairies, explored which suites of predictive variables produced the best ecological niche models, and explored two different approaches to the partitioning of data in evaluating models. We used a number of performance measures and expert evaluation to select our best models. The best model was developed using a suite of climate variables and growing degree-days as the predictive variables and by partitioning testing and training data using stratified random sampling. The model indicated that Purple Loosestrife has not yet reached its full potential distribution in the Prairies. The modelling techniques presented in this paper may be used to predict the potential distribution of other emerging invasive plants, and the results can be used to optimize early detection and surveillance strategies for Purple Loosestrife in areas of the Prairies.

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18. Controlling Purple Loosestrife Populations in the Kingston and Surrounding Areas

Inquiry@Queen's Undergraduate Research Conference Proceedings ◽

10.24908/iqurcp.9435 ◽

2018 ◽

Author(s):

Keenan Randall ◽

Ty Greene ◽

Melissa Lee ◽

Carlyn McNabb

Keyword(s):

Invasive Species ◽

Invasive Plant ◽

Community Organization ◽

Human Life ◽

Control Agent ◽

Lythrum Salicaria ◽

Purple Loosestrife ◽

Native Plant ◽

Local Resident ◽

The Impact

Purple loosestrife (Lythrum salicaria) is an invasive plant species that has affected agriculture and wildlife across Canada. The weed is not native to Canada; however in municipalities like Kingston and the surrounding area, it has caused tangible problems. We will strive to engage a government partner (City of Kingston), community organization (ON Invasive Species Awareness Program), and a local resident throughout the completion of our research and regarding the viability of solutions proposed. First, we will examine the origins of the plant in Canada, emphasizing the reproductive characteristics that make the purple loosestrife a powerfully invasive species. Next, we will analyze the impact of the purple loosestrife from three perspectives: (1) the impact on native plant communities; (2) the impact on native animal communities; (3) the impact on human life. We will then evaluate current bio management controls, as utilized by other governments, such as the introduction of another foreign species as a control agent. Specifically, we will examine the potential control systems using the following criteria: (1) ability to control the invasive species; (2) feasibility and cost; and (3) direct and indirect negative impacts. Finally, we will propose a comprehensive strategy for each organization moving forward, allowing for increased community collaboration and, ideally, the elimination and/or control of the invasive species.

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Constraints in range predictions of invasive plant species due to non-equilibrium distribution patterns: Purple loosestrife (Lythrum salicaria) in North America

Ecological Modelling ◽

10.1016/j.ecolmodel.2004.04.020 ◽

2004 ◽

Vol 179 (4) ◽

pp. 551-567 ◽

Cited By ~ 64

Author(s):

Erik Welk

Keyword(s):

North America ◽

Plant Species ◽

Invasive Plant ◽

Equilibrium Distribution ◽

Distribution Patterns ◽

Lythrum Salicaria ◽

Purple Loosestrife ◽

Invasive Plant Species ◽

Non Equilibrium

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Host Specificity and Environmental Impact of the WeevilHylobius transversovittatus, a Biological Control Agent of Purple Loosestrife (Lythrum salicaria)

Weed Science ◽

10.1017/s0043174500084289 ◽

1994 ◽

Vol 42 (1) ◽

pp. 128-133 ◽

Cited By ~ 27

Author(s):

Bernd Blossey ◽

Dieter Schroeder ◽

Stephen D. Hight ◽

Richard A. Malecki

Keyword(s):

Biological Control ◽

North America ◽

Invasive Plant ◽

Negative Impact ◽

Biological Control Agent ◽

Control Program ◽

Classical Biological Control ◽

Lythrum Salicaria ◽

Purple Loosestrife ◽

Test Plant

Introduction of purple loosestrife into North America and its spread into wetlands has led to the degradation of these important habitats for wildlife. Conventional control efforts are unsuccessful in providing long-term control. A classical biological control program offers the best chance for reducing the numbers of this invasive plant and improving regeneration of the native flora and fauna. European studies demonstrated that the root boring weevil Hylobius transversovittatus is highly host specific to the target weed. Attack of two test plant species (winged lythrum and swamp loosestrife) during host range screening was most likely due to artificial test conditions. An environmental assessment of the potential effects of the release of the purple loosestrife borer in North America indicated that benefits outweigh any potential negative impact Therefore its field release was approved in 1992.

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Aspects of floral modification and style-morph frequencies in a colonizing weed, Lythrum salicaria (Purple loosestrife)

10.14321/j.ctt1pwtcm0.27 ◽

1995 ◽

pp. 471-482

Author(s):

Tarun K. Mal

Keyword(s):

Lythrum Salicaria ◽

Purple Loosestrife

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Effect ofGalerucellaspp. on survival of purple loosestrife (Lythrum salicaria) roots and crowns

Weed Science ◽

10.1017/s0043174500091906 ◽

1999 ◽

Vol 47 (3) ◽

pp. 360-365 ◽

Cited By ~ 16

Author(s):

Elizabeth J. Stamm Katovich ◽

Roger L. Becker ◽

David W. Ragsdale

Keyword(s):

Plant Stress ◽

Growing Season ◽

Lythrum Salicaria ◽

Purple Loosestrife ◽

Biological Control Agents ◽

Plant Mortality ◽

Galerucella Calmariensis ◽

Galerucella Pusilla ◽

Crown Tissue ◽

Severe Leaf

Starch levels, used as a measure of plant stress, were not consistently reduced in root or crown tissue of purple loosestrife plants after 2 yr of severeGalerucella calmariensisorGalerucella pusilla(Coleoptera: Chrysomelidae) defoliation. Early in the season, defoliation fromGalerucellaspp. approached 100%, but the majority ofLythrum salicariaplants regrew by the end of August, resulting in an average reduction of 81% of the aboveground biomass compared to the control. The stress imposed byGalerucellaspp. defoliation was less than that achieved from more severe stress imposed by mechanical shoot clipping at 2- or 4-wk intervals from June to October. Both shoot-clipping treatments killed the majority of plants after one growing season.Galerucellaspp. feeding reduced plant stature, which may reduce competitiveness. However, considering the extensive carbohydrate reserves present in the large woody crowns ofLythrum salicaria, it will require in excess of 2 yr of consistent, severe leaf defoliation to cause plant mortality. A combination of stresses, such as winter crown injury, or other biological control agents in addition toGalerucellaleaf defoliation may be required for plant mortality.

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Influence of Nontarget Neighbors and Spray Volume on Retention and Efficacy of Triclopyr in Purple Loosestrife (Lythrum salicaria)

Weed Science ◽

10.1017/s0043174500093681 ◽

1996 ◽

Vol 44 (1) ◽

pp. 143-147 ◽

Cited By ~ 6

Author(s):

Elizabeth J. Stamm Katovich ◽

Roger L. Becker ◽

Brad D. Kinkaid

Keyword(s):

Plant Density ◽

Spray Deposition ◽

Soil Surface ◽

Lythrum Salicaria ◽

Purple Loosestrife ◽

Central Target ◽

Basal Portion ◽

Spray Volume ◽

Vegetative Propagules ◽

Target Plant

Greenhouse studies were conducted to determine the influence of plant density and spray volume on the retention, spray deposition, efficacy, and translocation of the amine salt of triclopyr in purple loosestrife. More spray solution was retained on leaves at 935 Lha−1than at 94 Lha−1at populations of 0, 4, or 8 nontarget neighbors. Spray coverage decreased with decreasing height within the plant canopy when spray cards were placed in the top, middle, and soil surface adjacent to the central target plant. Within a population, spray card coverage generally increased as spray volume increased. Regrowth from the crown was affected by spray volume, and uniform spray coverage of the plant was required for adequate control of vegetative regrowth and was achieved with spray volumes of 374 and 935 L ha−1spray volume. Regrowth of purple loosestrife was greater at 94 Lha−1at all three plant populations indicating that less herbicide penetrated the canopy to reach the basal portion of the plant. A laboratory experiment was conducted to investigate the translocation of radiolabelled triclopyr to roots and crowns of purple loosestrife. Only 0.3 to 1.4% of absorbed14C-labelled material was translocated to roots and crowns. Low spray volumes and dense stands of purple loosestrife would likely result in poor control because inadequate amounts of triclopyr reach the basal portion of the plant and translocate to vegetative propagules.

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