L’antagoniste du cynips du châtaignier est en Suisse!

Torymus sinensis, le parasitoïde exotique lâché en Italie pour lutter contre le cynips du châtaignier a été détecté pour la première fois en Suisse, au Tessin. L’insecte est arrivé naturellement malgré les précautions environnementales prises par la Suisse.

Un article paru dans La Regione Ticino mardi 10 septembre 2013, PDF


“Cinipide, la lotta biologica funziona” by Luca Berti, in La Regione Ticino

Torymus sinensis, a chinese hymenopteran parasitoid is considered as the only antagonist of the chestnut gall wasp Dryocosmus kuriphilus. After the invasion of the gall wasp in Ticino’s chestnut forests, cantonal authorities sought an homologation of T. sinensis by the Federal Office for the Environment. A very good paper by Luca Berti (published the 4th of July 2012 in La Regione Ticino) summarizes the biosafety questions raised by this classical biological control example and the international situation where different countries regulate the introduction of exotic natural enemies differently. The paper (in italian) can be read here PDF

Predation of native coccinellids by the invasive alien Harmonia axyridis (Coleoptera: Coccinellidae): detection in Britain by PCR-based gut analysis

First field quantification of intraguild predation by the asiatic invasive ladybird Harmonia axyridis, at the species level on native ladybird species (Adalia bipunctata and A. decempunctata).

THOMAS A, TROTMAN J, WHEATLEY A, AEBI A, ZINDEL R and  BROWN PMJ(2013) Predation of native coccinellids by the invasive alien Harmonia axyridis (Coleoptera: Coccinellidae): detection in Britain by PCR-based gut analysis. Insect Conservation and Diversity 6:20-27 PDF

Torymus sinensis: a viable management option for the biological control of Dryocosmus kuriphilus in Europe?

The chestnut gall wasp Dryocosmus kuriphilus is a global pest of chestnut (Castanea spp). Established as a pest in the mid-twentieth century in Japan, Korea and North America, this species was first reported in Europe in 2002. Following the successful release of a biological control agent Torymus sinensis in Japan, this parasitoid species has been released in Italy since 2005. Here we discuss the potential of T. sinensis as a viable management option for the biological control of D. kuriphilus in central Europe. We suggest that more consideration should be given to determining, (i) the conditions under which T. sinensis may attack alternative native gall wasp hosts and (ii) the likelihood of hybridization of this species with native Torymus. Both issues are central to predicting unassisted range expansion by released T. sinensis, and to assess the environmental risks associated with a more widespread release of this species in Europe.

Melanie Gibbs, Karsten Schönrogge, Alberto Alma, George Melika, Ambra Quacchia, Graham N. Stone and Alexandre Aebi (2011) Torymus sinensis: a viable management option
for the biological control of Dryocosmus kuriphilus in Europe? 56:527–538 DOI 10.1007/s10526-011-9364-8

Is Dryocosmus kuriphilus present in Switzerland? Yes. An evaluation of the use of T. sinensis in Ticino in a socio-economical context can be downloaded here.

Aebi A, Schönenberger N, Bigler F (2011) Evaluating the use of Torymus sinensis against the chestnut gall wasp Dryocosmus kuriphilus in the Canton Ticino, Switzerland. Agroscope Reckenholz-Tänikon Report (ISBN: 978-3-905733-20-4) pp. 71

Detecting arthropod intraguild predation in the field

Picture: Mario Waldburger

The process of biological control carries a distinct risk that an alien biological control agent (BCA) will become established as an invasive alien species with an associated threat to the local ecosystem biodiversity. It is imperative that a wide-ranging environmental risk assessment (ERA) is performed before the release of any BCA. This should include considering various potential but difficult to observe ecological interactions between the BCA and members of the native community, including disruption of intraguild relationships. Detection of intraguild predation (IGP) events involving predatory arthropods in the field can be done by analyzing their gut contents. Polymerase chain reaction (PCR) is a sensitive and specific tool to identify target prey DNA within a predator’s gut. This paper reviews the efficiency of a DNA based approach for detecting IGP in the field, compared with detection by the use of monoclonal antibodies or gas chromatography. Prey specificity, detection times after prey consumption, capacity for quantification, multiple prey targeting and the time and costs involved in developing and using the different methods are considered.

Aebi A, Brown PMJ, de Clercq P, Hautier L, Howe AG, Ingels B, Ravn HP, Sloggett JJ, Zindel R and Thomas A (2011) Measuring arthropod intraguild predation in the field. BioControl 56:429–440 DOI 10.1007/s10526-011-9378-2