PART 1. A FEW DEFINITIONS
1. Pest, crop protection and natural regulation
* Pest: from injuries to economic losses
* Natural regulation in crop protection strategies
2. Plant diversification in agricultural areas
* Increasing crop intraspecific diversity: varietal mixtures, use of heterogeneous varieties (farmer, traditional), etc.
* Increasing the interspecific diversity of the cultivated cover: mixed cropping, service plants, agroforestry, etc.
* Increasing the temporal diversity of cultivated plants: diversified rotations
* Diversity of semi-natural vegetation in the landscape: hedgerows, permanent grasslands, groves, etc.
* Managing the level of diversity in the landscape

PART 2. LESSONS LEARNED FROM THE COLLECTIVE SCIENTIFIC ASSESSMENT
3. Agroecological impacts of plant diversification
* Diversifying the vegetation on agricultural fields and landscapes is a crop protection lever
* Plant diversification is good for the associated biodiversity and the ecosystem services provided to farmers and society
* Diversified systems often provide higher yields than poorly diversified systems
4. Implementing plant diversification to protect crops
* Introduction
* Plant diversification has contrasting effects on short-term farm profitability
* To encourage plant diversification, several obstacles must be removed both within agricultural supply chains and at the territorial level
* Public policies are a key factor in the deployment of plant diversification

PART 3. OUTLOOK AND RESEARCH NEEDS
5. Perspectives: plant diversification and environmental challenges
* What role can plant diversification play in the transition to pesticide-free agriculture?
* Plant diversification of agricultural systems to meet the challenges of climate change
* To what extent should we diversify? Some recommendations from the scientific literature
6. Further research and studies needed
* Gaining a better understanding of the natural regulation mechanisms of pests
* Gaining a better understanding of socio-economic organisations
* Building on long-term research and using digital tools…
* … to design public policies that foster diversification

Conclusion
Annex. The turning point in the Common Agricultural Policy that paved the way for plant diversification
* Greening the 2014 reform: An admission of failure?
* The promises of the post-2020 CAP reform
Selected references
Composition of the working group
Image and photo credits