©Xavier Remongin/Min.agri.fr

A vast international consortium of researchers involving France’s leading agricultural research institute, National Institute for Agricultural Research (INRA), and the University of California at Davis and Stanford University, highlighted the existence of a large variability in answers concerning the effect of the composition of countryside surrounding farms in controlling bio-aggressors like pests and weeds. This results from a meta-analysis of more than 130 studies representing more than 18,000 observations of natural enemies of pests and weeds spread across 6,700 sites in 31 different countries.

Optimizing the natural control of bio-aggressors is a major issue for the development of agroecology and for reducing the use of phytosanitary products like pesticides and herbicides. For the past two decades, a paradigm has emerged in that matter, indicating that the composition of agricultural countryside, and particularly how much of it is devoted to semi-natural habitats (forests, hedges, native prairies, etc.), is an important factor in explaining the activity of natural enemies of pests and weeds.

The scientists found that this composition of countryside surrounding farms is indeed a relevant factor. Some of the studies prove positive impacts of semi-natural habitats while some suggest an opposite result: the meta-analysis thus helped to identify the ideal conditions for the use of semi-natural habitats and where they can have the most positive impact. The research underlined the importance of the natural context in developing solutions to different groups of natural pest and weed enemies.

The scientists are currently continuing their work, looking for ways to integrate other variables into the equation to help better identify the situations that encourage natural control of pests and weeds. A global database has been put together that will continue to be updated and made available to the public for all to be able to analyze the data and put it to use on their farms.