Ulrich KUHLMANN & Stefan TÖPFER
CABI Bioscience Centre, Rue des Grillons 1, 2800 Delémont, Switzerland

The possibilities for biological control of western corn rootworm (WCR) using natural enemies as biological control agents will be considered within the EU Project DIABROTICA that either occur in the area of origin of WCR in Central/South America or which are native to the European agro-ecosystems. The native natural enemy guild of WCR will be studied in southeastern Europe to characterise both structure (biodiversity) and function of the natural enemy community present. Findings from this study will provide information about host niches of WCR that are presently not attacked by the natural enemy guild in southeastern Europe.

In collaboration with Dr Astrid Eben (Mexico) and Dr Willie Cabera Walsh (Argentina) the natural enemy guild of WCR from the area of origin in Central/South America will be studied to identify potential natural enemies (i.e. parasitoids and predators). The study aims to select specific biological control agents of WCR for potential importation and establishment in Europe. Preliminary studies will be carried out on the biology and ecology of specific natural enemies in its area of origin. Selected exotic parasitoid or predator species will be further tested by CABI-CH in a quarantine laboratory at Delémont, Switzerland, with the intention of selecting and testing candidate biological control agents for potential importation into Europe. With regard to the safety of biological control the guidelines of the European and Mediterranean Plant Protection Organisation (EPPO) for the importation and release of exotic natural enemies will be followed. Guidelines and recommendations are currently elaborated by the EU-Project FAIR-3489; and exchange of information will guarantee that most recent testing procedures will be used.

Prior to the importation of exotic biological control agents the host specificity of the agent has to be identified to allow us to predict their field host range and to evaluate potential non-target risks. These pre-release studies are as follows: (1) assessment of the phylogenetic, ecological and behavioural affinities of the target hosts with the native and other non-target fauna to identify potential “at risk” non-target species, (2) examine the degree of habitat overlap between target and identified non-target host species, and (3) assess the laboratory host range of natural enemies under test conditions. On the basis of these criteria predictions will be made about which taxa are likely to be at risk, what the impact might be and habitats where this might occur will be identified. Field sampling will be carried out to assess the realised host range for comparison with that predicted in the pre-release quarantine laboratory studies.