Fine-tuning of a mowing regime, a method for the management of the invasive plant, Ambrosia artemisiifolia, at different population densities

Citation: Milakovic, I., Fiedler, K., Karrer, G. (2014) Fine-tuning of a mowing regime, a method for the management of the invasive plant, Ambrosia artemisiifolia, at different population densities. Weed Biology and Management14 ( 4 ) pp. 232 – 241

Wiley Online Library

Abstract: Common ragweed (Ambrosia artemisiifolia) is an invasive annual plant with highly allergenic pollen. Its spread in introduced and native ranges often occurs on roadsides, where it builds stable and rapidly growing populations. The most sustainable way of controlling the population size of this species is to prevent seed production in order to deplete the soil seed bank. Populations on roadsides are submitted to regular mowing management, which can even exacerbate the situation by inducing resprouting after cutting or by accidentally spreading seeds along the road. The population density in the juvenile stages of development could play an important role in the success of cutting regimes, as it might influence the resprouting capacity of this plant. The influence of the juvenile population density and of seven cutting regimes, differing in the timing and frequency of cuts, on easily measurable reproductive traits was investigated in a glasshouse experiment. The cutting regimes had a strong influence on the reproductive success and on the phenology of the development stages of ragweed. The population density in the juvenile stages did not play a role in further phenological development, but did influence the reproductive traits. The reproduction of ragweed can be lowered by locally adapted combinations of the timing and frequency of mowing. As the optimal management option for the reduction of both the male and female flowers, the authors suggest a first cut just before the start of male flowering, followed by subsequent cuts every 3–4 weeks.

Ground cover species selection to manage common ragweed (Ambrosia artemisiifolia L.) in roadside edge of highway

Citation: Bae, J., Byun, C., Watson, A.K., Benoit, D.L. (2014) Ground cover species selection to manage common ragweed (Ambrosia artemisiifolia L.) in roadside edge of highway. Plant Ecology,

Springer Link

Abstract: In southern Quebec, Canada, Trifolium species are commonly used as supplement ground cover along roadside of major roads to assist turf recruitment. They often fail to establish particularly near roadside edges. The noxious weed, Ambrosia artemisiifolia, exploits the empty niches. Based on an assumption that heavy metal stress mainly drives plant species shift, we conducted a field experiment to test the emergence of four species near roadside edges along a metal gradient. The test species included a clover ground cover (Trifolium arvense), two candidate ground covers (Lotus corniculatus and Coronilla varia), and the weed (A. artemisiifolia). Two hundred wet-cold stratified seeds of each species were sown in plots (20 × 30 cm), assigned separately for one of four species treatments, replicated three times. We measured final emergence percentage and soil metal contents and analyzed their correlations. T. arvense emergence was negatively correlated with Zn, Pb, and Cu. In contrast, A. artemisiifolia emergence was positively correlated with Zn, Pb, and Cu. The experiment supports the hypothesis that A. artemisiifolia colonization along roadside edges may be attributing to its greater tolerance for Zn, Pb, and Cu than T. arvense. In evaluating the two legume candidates, L. corniculatus was positively correlated with Zn, Pb, and Cu like A. artemisiifolia, while C. varia emergence did not have significant relationship with Pb and Cu. The current finding implies that L. corniculatus can be a good candidate because of its emergence performance and its tolerance to heavy metal, similarly to that of A. artemisiifolia.

Ophraella and Ambrosia pollen flying on TV (6-minute videos)

This summer, a television crew visited the University of Fribourg research facilities in Switzerland, and two field sites in Italy where an international team led by Heinz Müller-Schärer has been investigating the effects of the ragweed leaf beetle Ophraella communa.

Watch the resulting movies that were broadcast on the popular science shows  Nano (Switzerland) or Einstein (Austria, Germany, Switzerland). The potential benefits for the control of ragweed, and the potential risks for other plant species are presented.

The movies are in German, but you can anyway enjoy the images of flying beetles and Ambrosia pollen without understanding the spoken words! The websites contain additional interviews on the Ambrosia problem.

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SMARTER@Neobiota Conference on invasive species


Prof. Heinz Müller-Schärer presenting the COST action SMARTER

A number of SMARTER members presented their work on ragweed at Neobiota 2014, the 8th International Conference on Biological Invasions: From understanding to action (3-8 November, Antalya, Turkey).

The 15 studies presented covered a range of different topics, including: distribution patterns and pathways of introduction in particular countries, understanding phenotypic variation and the invasion process, testing the effects of herbicides and biological control methods, and successful management strategies.

Poster presentations by SMARTER members about ragweed

Oral presentations by SMARTER members about ragweed

  • Uwe Starfinger (Germany): Can the invasion of common ragweed be halted? New insights from an international project
  • Baruch Rubin (Israel): Ambrosia confertiflora in Israel – weed invasion and possible management
  • Božena Mitić (Croatia): Invasive alien plants in Croatia – distributional patterns and range size
  • Hüseyin Önen (Turkey): The Black Sea highway: the route of common ragweed invasion in Turkey
  • Suzanne Lommen (Switzerland): A SMARTER approach to assess the impact of an established, exotic leaf beetle on invasive ragweed Europe
  • Heinz Müller-Schärer (Switzerland): The ragweed leaf beetle landed in Europe: fortunate introduction or threat?
  • Florencia Yannelli (Germany): Limiting similarity by functional group resemblance: Preventing plant invasion during grassland restoration