Short description
(English)
|
The North American plant Ambrosia artemisiifolia has become one of the flagship invasive alien species in Europe, causing severe health issues and impact in agriculture. While herbicides and mechanical control are well suited as local and short-term measures to control A. artemisiifolia, sustainable control strategies to mitigate Ambrosia's further spread and to reduce its abundance in badly infested areas are lacking in Europe. One of the main objectives of COST-SMARTER is to develop sustainable control strategies such as classical biological control (BC), an approach which has been successfully implemented against A. artemisiifolia on other continents. Here we propose to conduct biosafety studies with exotic insect species that are considered for BC of A. artemisiifolia in Europe. The goal is to generate knowledge that will be central for the risk assessment by European authorities when evaluating petitions for field release of BC candidates against this problematic invader which is one of the main goals of Working Group 1 (Biological control) of COST-SMARTER. We will combine standard biosafety tests (assessment of fundamental host-range) with new, innovative approaches that will strengthen the scientific quality of non-target risk assessment, specifically with regard to i) host-range testing under open-field conditions, and ii) prediction of the population dynamics of BC candidates prior to their release into a new environment.
|
Abstract
(English)
|
The North American plant Ambrosia artemisiifolia has become one of the flagship invasive alien species in Europe, causing severe health issues and impact in agriculture. In Europe, sustainable control strategies to mitigate Ambrosia’s further spread and to reduce its abundance in badly infested areas are lacking. One of the main objectives of COST action “SMARTER” is to develop sustainable control strategies such as classical biological control (BC), an approach which has been successfully implemented against A. artemisiifolia on other continents. In this project we will generate knowledge that will be central for the risk assessment by European authorities when evaluating the use of BC agents in the management of this problematic weed. Recently, two insect species successfully used as BC agents in Australia and/or China have established in Europe, i.e. the moth E. strenuana in Israel and the ragweed leaf beetle Ophraella communa in southern Switzerland and northern Italy. We will focus on these two species and aim to combine standard biosafety tests (assessment of host specificity) with the development of a climate-depending demographic model that will help predicting the suitability of the European climate for establishment and population build-up of a BC agent and its related impacts on target and non-target species. During the first project year, we started developing a continuous time model for O. communa and conducted a series of field and laboratory experiments to collect data on the climate dependent longevity, fecundity and growth rate of O. communa; these data will then be used to parametrize the model. In the invaded range in northern Italy, we set up field cages with ragweed plants along an altitudinal gradient in the southern Alps that covers a temperature range of 8 °C, and monitored population build-up and female fitness during the field season. Also, to assess the effect of temperature and humidity on longevity and fecundity of adult beetles, egg hatching rates and larval development, we initiated several laboratory experiments covering a temperature range of 14 °C. First results suggest that both temperature and humidity significantly affect various life-history transitions in O. communa. For example, while in the warmer parts of northern Italy O. communa has a generation time of approximately one month and produces four generations per year, this insect species can also establish at altitudes above 1000m, but under these cooler conditions it only produces one generation per year. Relative humidity of < 30% largely prevents egg hatching; these values can be reached during the daytime in some areas in Europe heavily invaded by common ragweed, e.g. the Pannonian plane in eastern Europe. During the second year of the project we will continue with open-field and laboratory experiments to collect data on the climate-dependent life-history transitions in O. communa and then use the results to parametrize the continuous-time stage structured model. We will include the non-target species sunflower in our experiments in order to model the climate-dependent demography of O. communa on this most important non-target species. In addition, we plan to carry out field surveys and open-field experiments with O. communa in southern Switzerland/northern Italy and with E. strenuana in Israel to improve our understanding of the host-specificity of these two biocontrol candidates under natural and semi-natural conditions.
|
