Symbiosis disruption in the olive fruit fly, Bactrocera oleae (Rossi), as a potential tool for sustainable control

Martina Sinno (1) , Annie Bezier (2) , Francesco Vinale (1) , David Giron (2) , Stefania Laudonia (1) , Antonio P Garonna (3) , Francesco Pennacchio (1)

1 University of Naples Federico II = Università degli studi di Napoli Federico II
2 IRBI - Institut de recherche sur la biologie de l'insecte
3 Dipartimento di Agraria

BACKGROUND: The olive fruit fly Bactrocera oleae (Rossi) (OLF) is a major agricultural pest, whose control primarily relies on the use of chemical insecticides. Therefore, development of sustainable control strategies is highly desirable. The primary endo-symbiotic bacterium of OLF, 'Candidatus Erwinia dacicola', is essential for successful larval development in unripe olive fruits. Therefore, targeting this endosymbiont with antimicrobial compounds may result in OLF fitness reduction and may exert control on natural populations of OLF. RESULTS: Here, we evaluate the impact of compounds with antimicrobial activity on the OLF endosymbiont. Copper oxychlor-ide (CO) and the fungal metabolite viridiol (Vi), produced by Trichoderma spp., were used. Laboratory bioassays were carried out to assess the effect of oral administration of these compounds on OLF fitness and molecular analyses (quantitative polymer-ase chain reaction) were conducted to measure the load of OLF-associated microorganisms in treated flies. CO and Vi were both able to disrupt the symbiotic association between OLF and its symbiotic bacteria, determining a significant reduction in the endosymbiont and gut microbiota load as well as a decrease in OLF fitness. CO had a direct negative effect on OLF adults. Conversely, exposure to Vi significantly undermined larval development of the treated female's progeny but did not show any toxicity in OLF adults. CONCLUSIONS: These results provide new insights into the symbiotic control of OLF and pave the way for the development of more sustainable strategies of pest control based on the use of natural compounds with antimicrobial activity.

Domaines: Zoologie des invertébrés; Sciences et techniques de l'agriculture

Martina Sinno, Annie Bezier, Francesco Vinale, David Giron, Stefania Laudonia, et al.. Symbiosis disruption in the olive fruit fly, Bactrocera oleae (Rossi), as a potential tool for sustainable control. Pest Management Science, 2020, 76 (9), pp.3199 - 3207. ⟨10.1002/ps.5875⟩. ⟨hal-02637937⟩