SuzoCarpo

Project financing: 

Total budget: 354 763,12 euro

PSH budget: 41 460 euro

Financier : Ecophyto II (OFB)

Time : 3 years (2023-2025)

Digest:

Through initial introductions of exotic parasitoids, combined with post-introduction monitoring and population dynamics approaches, the project aims to (i) define the optimal conditions to acclimate parasitoids for the sustainable control of the pests Drosophila suzukii and Cydia pomonella, and (ii) prepare the large-scale deployment and integration of these two alternative control methods into crop management practices. The expected outcome is a substantial and lasting reduction in pest densities, at no cost to growers, which in turn will allow for a significant decrease in pesticide use.

PSH role:

Myriam Siegwart works on the compatibility of parasitoids release with (bio)pesticides
Biological control can be strongly affected by pesticides and exclusion nets, which alter insect survival and mobility. This action will assess in laboratory conditions: (i) the toxicity of key pesticides used in orchards, under both organic and conventional management, on the introduced parasitoids M. ridens and G. cf. brasiliensis, and (ii) the effect of plastic nets commonly used in fruit production on their dispersal ability. Preliminary results obtained at INRAE PSH (toxicity of three insecticides, including spinosad, on M. ridens) will be extended to other products, in particular fungicides. These bioassays will also evaluate the complementarity between nets and parasitoids, given that C. pomonella adaptations to nets have already been reported. Finally, the results will contribute to exploring the potential of “augmentorium” systems, designed both to eliminate pest hotspots (infested fruits, trap-bands) and to promote the multiplication of introduced parasitoids as well as native beneficials.

Bertrand Gauffre, Claire Lavigne and Pierre Franck are involved in the characterization of factors driving the establishment and spread of Mastrus ridens :
They tri to identify the ecological, climatic and agronomic factors influencing the successful establishment of M. ridens. Between 2019 and 2021, the parasitoid was released in 57 French orchards, where post-introduction monitoring will combine trap-bands, sentinel larvae, and an innovative male recapture method using sex pheromones. At the national scale, these surveys will be complemented by damage assessments on fruits, while at the local scale (Basse Vallée de la Durance experimental site), intensive sampling in release orchards and surrounding landscapes will evaluate the role of agricultural practices, landscape structure and agroecological infrastructures in parasitoid establishment. Emerging parasitoids (exotic and native) will be identified using morphological and molecular tools, and landscape maps will be used to relate community composition to environmental drivers. Statistical analyses will determine the factors (landscape, practices, genetics) shaping establishment success and parasitoid community dynamics. In addition, historical datasets will be mobilized to assess how spatial and temporal stability of landscapes, as well as interspecific interactions, influence parasitism rates, community diversity, and long-term host–parasitoid dynamics.