In collaboration with Nathalie Boissot (INRAE-GAFL Montfavet) I am interested in the coupling between genetic control and cultural practices that reduce bioaggressors in a perspective of sustainability.
This axis of research focuses on the major gene Vat, which confers resistance to colonization by Aphis gossypii and resistance to viruses transmitted by these aphids (Boissot et al., 2016). In the field, this results in a significant reduction in outbreaks of CABYV, a virus transmitted mainly by Aphis gossypii in the persistent mode, but ineffectiveness on outbreaks of WMV, a virus transmitted by other aphid species in the non-persistent mode (Schoeny et al. 2017)

Therefore, the use of Vat is usually coupled with aphicide treatments to limit viral transmission by the non-colonizing "visitor" aphids of melon crops. However, the gradual reduction in the use of plant protection products in crop protection imposed by the evolution of the legislation leads to the search for new strategies to accompany genetic control for the management of bio-aggressors.

The hypothesis we tested is that the implementation of flower strips near to the crop can contribute to the regulation of aphid populations and/or their viruliferous potential, thus increasing the effectiveness and durability of resistance mediated by the Vat gene.
Large-scale experiments to test the effect of the combination of Vat x field margin management (in particular bare soil and flower strips) were conducted for 5 years in Avignon.
Flower strips sown with a mix of these five plant species (cornflower, grass pea, sainfoin, salad burnet and sweet marjoram) displayed a flowering continuum likely to provide a food resource to natural enemies throughout the growing season. Their potential to host/enhance natural enemies was compared to those of bare soil. Most generalist and specialist predators analyzed responded positively to the floral resources displayed. In particular, coccinellid and syrphid fluxes were significantly enhanced near flower margins.
We also showed that flower strips could enhance Vat efficiency to limit CABYV and WMV epidemics.

Another promising area of research concerns techniques that disrupt the installation of pests in crops, including the use of repellent plants. Recent research shows that aromatic plants such as rosemary or French marigold disturb the fecundity and nutritional behaviour of Myzus persicae on pepper (Dardouri et al. 2019; Dardouri et al., 2021).
An assessment of the effect of these service plants on the acquisition and inoculation of persistent and non-persistent viruses is currently underway as part of the MultiServ project.

Aromatic plants repellent towards aphids : (A) rosemary (Rosmarinus officinalis), (B) French marigold (Tagetes patula nana)

 Regardless of the strategies considered (chemical, cultural, biological, etc.), vector control remains a challenge due in particular to insufficient knowledge of the dynamics of arrival of vectors and the proportion of them carrying viruses (viruliferous).
As part of the BEYOND project we will develop molecular tools (qRT-PCR) allowing us to detect/quantify the presence of viruses in their vectors in order to be able to characterize the arrival of viruliferous vectors likely to initiate viral epidemics.