WIDE-Synergies · Towards a synergistic management of Weeds, Insect herbivores and Diseases with their natural Enemies in pesticide-free agroecosystems

Towards a synergistic management of Weeds, Insect herbivores and Diseases with their natural Enemies in pesticide-free agroecosystems

Agricultural landscapes have been homogenised in order to achieve economies of scales. While non-crop habitats have become scarcer, fields have been cultivated with pure stand crops. However, simplified cropping systems entrenched in homogeneous landscapes are more sensitive to pest and pathogen colonization and spread, less prone to biological control by natural enemies (i.e. predators and parasitoids), and more frequently and intensively treated with insecticides and fungicides. Simplified cropping systems are also more infested by weeds, hence more frequently and intensively treated with herbicides. The issue of pesticide use in agriculture is of crucial importance for society because their detrimental effects on the environment and human health are now well known. The European Union has decided to tackle the issue, with the very ambitious objectives of a 50 % reduction in the use and risk of chemical pesticides and a 50 % reduction in the use of more hazardous pesticides by 2030. In the present research, our aim was to test new agroecosystem design with the ambition to achieve an agriculture free of pesticides. Drastically reducing the use of pesticides requires redesigning agroecosystems. New agroecosystems have to diversify by maximizing functional biodiversity in order to reduce cropping system sensitivity to pests and favour their regulation by natural enemies (i.e. conservation biological control). Practices aiming at diversifying crop fields and the landscape are known and their beneficial impact on pests and their regulation has been studied. They include intercropping, that is the simultaneous cultivation of two or more crop species (or genotypes) coexisting in the field at least for a time; and the implementation and management of non-crop habitats at field margins such as pluriannual wildflower strips. While each of these practices has often been studied solely to assess their effects on weeds, insect herbivores, diseases and their enemies separately, the strategic integration of these instruments, with a view on their multifunctional effects, was missing. The overall objective of the WIDE-Synergies project was to test whether synergies would arise from the interplay between intercropping and wildflower strips at enhancing the regulation of multiple pests and cropping system productivity.

Data: CORDIS, © European Union