Léa Bolis
PhD student
lea.bolis@unine.ch
PhD thesis project
My PhD project is the result of the collaboration between the Laboratory of Functional Ecology and the Entomology and Nematology group of the Agroscope (Swiss center of excellence for agricultural research). It focuses on finding sustainable control measures against insect pests associated with oilseed rape.
Context:
Winter oilseed rape (WOR, Brassica napus) is a very economically important crop and accounts for about 1/4th of vegetable oil consumption in Switzerland. This crop takes almost a year to develop until it is ready to harvest, which makes it particularly vulnerable to a wide variety of biotic and abiotic stresses. Various insect species from many different taxonomic groups are considered pests of WOR, impacting plant health throughout its entire development either simultaneously or successively.
The recent ban in European countries on neonicotinoid treatments coupled with the rise of resistance mechanisms in insects against remaining authorized substances drive the need for efficient alternative control measures.
Intercropping WOR, the effect of Faba bean:
Early testing in Agroscope highlighted the potential of cover cropping and intercropping with other plant species as “environmentally friendly” ways to reduce insect pest pressure in WOR fields. The mechanisms underlying such intercropping-induced changes in insect and host plant interactions are poorly understood and require more research.
During my PhD, I focus on the impact of intercropping faba bean (Vicia faba) with WOR on the production of secondary metabolites in the latter, then focusing on subsequent effects on behavior and performance of three of the most important insect pests found in Switzerland:
- The cabbage stem flea beetle (Psylliodes chrysocephala)
- The rape stem weevil (Ceutorhynchus napi)
- The pollen beetle (Brassicogethes aeneus)
Auxi-Gen project:
Another part of my thesis is within the framework of the Auxi-Gen project, which aims to uncover how different landscape structural elements within or around fields such as hedges, flower strips, grassland and meadow fallows could promote insect biodiversity and act as biological control service providers. This project was launched by the Geneva state office for agriculture and nature (OCAN) and has a duration of four years. My role in the project focuses on quantifying and characterizing insect pest migration, associated crop damage as well as parasitism rates in WOR fields with or without pest suppressive landscape.
