Aromatic plants to protect vines?

Investigating olfactory cues against insect vectors

General background to the topic: Over the past decades, the scientific literature has strongly described the need for new preventive approaches to achieve sustainable pest management1. One of the main reasons is that pest control based on pesticides alone provides only short-term help and has undesirable economic and environmental consequences2. Furthermore, natural plant signals can be used in Integrated Pest Management to develop alternatives to chemical pesticides, for example by using them to stimulate plant defences3. Indeed, plants can detect the volatile organic compounds of their neighbors, a phenomenon called "induced defense". Induced plants show faster and/or stronger activation of their various defense responses. Aromatic plants are known to synthesize large amounts of VOCs, which are related to defensive traits against pests4, or attraction of natural enemies5, yet there is not much research on how these volatiles may affect antagonistic interactions between the plants and insect herbivores in agroecological fields and more precisely on perennial plants. Vineyards, shape the appearance of entire landscapes, and therefore create unique ecosystems. In addition to their significant economic value, grapevines (Vitis vinifera) provide a multitude of services to people and nature. Flavescence dorée (FD) is an economically damaging quarantine disease of grapevines caused by phytoplasma strains and transmitted by the insect vector, leafhopper, Scaphoideus titanus (Hemiptera:Cicadellidae)6. While research on FD primarily focuses on its role as a plant pathogen, it is necessary to understand the ecological interactions between the host plant (grapevine), its insect vector (S. titanus), as the FD disease is the outcome of these interactions. Grapevines, emit VOCs related to insect damage and which have hardly been identified. Additionally, we only have very limited knowledge from lab experiments on the European grapevine moth on how VOCs of grapevines are related to resistant traits against herbivores or how VOCs affect the relationships between antagonist and mutualist insects,7,8. To date there is no scientific knowledge on how VOCs by aromatic plants may interact with the grapevine plants and the behavior of S. titanus.

PhD Thesis opportunity:

General objective of the thesis: The aim of this thesis project is to assess the role of volatile organic compounds emitted by neighbouring aromatic plants to disrupt the behaviour of S. titanus on receiver grapevines, with potential use for sustainable biocontrol solutions

Specific objectives and work programme

- Testing the effect of aromatic companion plants on the behaviour of S. titanus - Under controlled

conditions, different vine-aromatic plant associations (various cultivars and species) will be tested. The

attractiveness or repellent effect of these associations on leafhoppers, as well as their acceptance of the host plant,

will be measured.

- Assessing the medium-term effects on insect fitness - The effects of VOCs on the survival, fecundity and

development of S. titanus will be analysed in order to identify the plant associations most unfavourable to the longterm establishment of the vector.

- Detailed analysis of the vector's feeding behaviour - On the most promising vine-aromatic plant

combinations identified in the first two stages, detailed analyses of the insects' feeding behaviour will be carried out

using the electropenetrography (EPG) technique(10) (,11), to characterise the impact of VOCs on the stinging and

acquisition/transmission phases of the phytoplasma.

Profile required

✅Profile MSc in Entomology or Chemical Ecology 

✅Solid knowledge of biostatistics and an appetite for programming in R

✅Theoretical and practical knowledge of entomology and/or behavioural ecology would be a plus

✅Good level in French and English

✅Open to multidisciplinarity

Start date of thesis: October 2025

Host laboratory and collaborations

- The student will join the TEAM team of the UMR ABSYS joint research unit in Montpellier, whose 

general objective is to mobilise plant diversity in perennial crop systems, including agroforestry, 

in various Mediterranean and tropical environments, to support the agroecological transition.

- The student will be co-supervised by a member of the FORISK team at the Institut de la Santé des 

Plantes in Montpellier ( UMR PHIM), with whom he/she will interact closely, particularly for EPG 

analyses.

- The test plants and insects will be obtained from phytoplasma-free V. vinifera cuttings and in close collaboration with the UMR BFP and Sylvie Malembic-Maher and Sandrine Eveillard ,specialists in the vine-phytoplasm biological model.

Co-supervision

Foteini Paschalidou (CRCN-INRAE, UMR ABSYS, Montpellier) Nicolas Sauvion (HDR, IRHC-INRAE, UMR 

PHIM, Montpellier)

Funding: 36 months, HORIZON.1.1. - European Research Council (ERC) - PANOPLY project: "Do plant 

volatiles shape species interactions in agroecological fields?

How to apply: Send CV + covering letter + at least one letter of recommendation 

tofoteini.paschalidou@inrae.fr . nicolas.sauvion@inrae.fr

Dates :

- Deadline for receipt of applications: midnight on Friday 4 July 2025

- Hearings: week of 7 and 11 July 2025

- Publication of results: 15 July 2025