Improving our understanding of the impact of nature-based integrated weed management approaches against the invasive, highly allergenic plant Ambrosia artemisiifolia, thr
Thesis supervisor: Stefan Toepfer
co-supervisor: Zita Dorner
belső konzulens: Mihaly Zalai
Location of studies (in Hungarian): Mainly southern Hungary, partly at Godollo Campus of MATE (Dep. of IPM, Godollo campus, MATE), international experimentation and travel in Hungary, Croatia, and other countries Abbreviation of location of studies: HU
Description of the research topic:
Background
Ambrosia artemisiifolia (Asteraceae) is a serious invasive weed in Central Europe as well as Eastern Asia (Schaffner et al. 2020). It originated in the southern parts of North America where it has a set of natural enemies and is therefore only a minor weed problem. In contrast, it is a major and difficult-to-manage weed in the invaded areas. Moreover, it is highly allergenic to humans, causing annual health costs of several billion Euros in Europe (Schaffner et al. 2020).
Ambrosia is also a serious problem in Hungary (Kiss 2007). In fact, the central region of central Europe seems to have highly optimal conditions for the weed. The region is therefore among the most suffering with regard to agricultural and human health impacts; in Hungary, more than 30% of the people are sensitive to ragweed pollen (Schaffner et al. 2020). Cultural and mechanical management of A. artemisiifolia is challenging, as it is a fast-propagating weed, can quickly re-grow after cutting, and occurs in many different habitats, including crop fields, road margins and natural riparian ecosystems. It is moreover difficult to be controlled through herbicides in Asteraceaen crops such as sunflower. The leaf beetle Ophraella communa (Coleoptera: Chrysomelidae) of north American origin has been introduced into China as is now being used as a biocontrol agent. In 2013, O. communa was detected also in Europe, i.e. in northern Italy and southern Switzerland. Since then, airborne pollen concentrations in the Milano region, where the beetle builds outbreak populations, has dropped by 80% (Schaffner et al. 2020). First risk assessment studies have shown, however, that the beetle can develop not only on Ambrosia, but also on some closely related plant species, which warrants additional risk-assessment studies before the beetle can be proposed as biological control agent across Europe (Dernovici et al. 2006; Augustinus et al. 2020b). The beetle has now also been detected in Hungary (Horvath and Lukatsi 2020). Demographic models developed for O. communa suggest that parts of Hungary are suitable for O. communa, while in other parts it may not be able to build up high densities by itself (Augustinus et al. 2020a). Thus, provided the non-target risks of this beetle are negligible for Central Europe, one may consider combining natural control by O. communa (the ‘Classical Biological Control’ approach) with mass releases of the beetle early in the season (‘Inundative Biological Control’) to increase herbivory on ragweed. Such a combined approach is likely to reduce ragweed pollen concentration in Hungary and other countries in Central and Eastern Europe to a similar extent as it has already done in northern Italy.
Specific objectives:
1. Assessing the demography and impact of the biocontrol agent Ophraella communa on Ambrosia artemisiifolia in hot spots in Central Europe differing in climatic conditions, and updating and validating existing demographic models.
This includes field studies assessing or analysing vital rates of the biological control agent Ophraella communa (Chrysomelidae) in central European countries (HU; CRO; others). This will combine field surveys with field cage trials to study O. communa populations established in Central Europe. Results will then be used to update a demographic model of Ophraella communa (Augustinus et al. 2020a).
2. Designing a biological control based weed management approach against Ambrosia artemisiifolia
Although there are already plenty of studies on how to chemically and mechanically manage Ambrosia, little is known about biological approaches. The study will combine results from field and laboratory studies and existing models to assess how different biological control approaches, including classical and inundative biological control using O. communa and the use of botanical and/or microbial bioherbicides, can be integrated in the management of A. artemisiifolia across Europe.
3. Contributing to the European-wide risk assessment of O. communa for biological control of common ragweed Ambrosia artemisiifolia
Ophraella communa of north American origin has been introduced into China as a biocontrol agent. Risk assessments have shown, however, that the beetle may, in rare cases, also attack other plant species, and seem therefore not entirely safe (Dernovici et al. 2006; ZhenJun et al. 2011; Augustinus et al. 2020b). It is proposed to conduct no-choice and choice host-specificity tests with O. communa under laboratory and field conditions using plant species from central and eastern Europe that are closely related to A. artemisiifolia and thus potentially at risk of non-target attack by O. communa.
Student skills:
Biological, ecological and/or agricultural background or comparable; interest in field work, experimentation and modelling; Hungarian – English language preferable, team work, driving licence.
We offer:
Work in a very international team; linkage to different local and international projects potentially also an EU project (decision mid 2022); cutting edge science on an extremely important topic.
References
Augustinus B, Sun Y, Beuchat C, Schaffner U, and Müller-Schärer. 2020a. Predicting impact
of a biocontrol agent: integrating distribution modeling with climate-dependent vital rates. Ecological Applications 30, e02003.
Augustinus BA, Gentili R, Horvath D, Naderi R, Yan S, Tournet AMTE, Schaffner U, Müller-Schärer H, 2020b. Assessing the risks of non-target feeding by the accidentally introduced ragweed leaf beetle, Ophraella communa, to native European plant species. Biol. Control 150.
Dernovici SA, Teshler MP, Watson AK, 2006. Is sunflower (Helianthus annuus) at risk to damage from Ophraella communa, a natural enemy of common ragweed (Ambrosia artemisiifolia). Biocontrol Sci. Technol. 16, 669–686.
Horvath D, Lukatsi M, 2020. First record of Ophraella communa in Hungary (Coleoptera: Chrysomelidae). Folia Entomol. Hungarica 81, 73–79.
Kiss L, 2007. Why is biocontrol of common ragweed, the most allergenic weed in Eastern Europe, still only a hope?, in: Biological Control: A Global Perspective. CABI, Wallingford, 80–91.
Schaffner U, Steinbach S, Yan S, Skjøth CA, Weger LA de, Lommen ST, Augustinus BA, Bonini M, Karrer G, Šikoparija B, Thibaudon M, Müller-Schärer H, 2020. Biological weed control to relieve millions from Ambrosia allergies in Europe. Nat. Commun. 11.
Cao Z, Wang H, Meng L, Li B, 2011. Risk to nontarget plants from Ophraella communa (Coleoptera: Chrysomelidae), a potential biological control agent of alien invasive weed Ambrosia artemisiifolia (Asteraceae) in China. Appl. Entomol. Zool. 46, 375–381.
Required language skills: English, Hungarian Number of students who can be accepted: 1
Deadline for application: 2024-05-31
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
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