Increasing crop diversity reduces pesticides across diverse production situations

Abstract

Pesticides have caused significant losses of biodiversity and pose a threat to human health. Crop diversification is proposed as a major solution to achieve the needed pesticide reduction in agriculture, by moderating the pressure of weeds, insect pests, and fungal diseases. According to the pest triangle framework, the impact of a pest outbreak depends on the interactions between crop, pest, and the environment. Diversifying crop sequences in a cropping system could impact the interactions between the three factors and recalibrate the need for pesticides to control pests and avoid yield losses. A previous study found that pesticide use, measured by the Treatment Frequency Index at the cropping system level, is affected both by crop species and crop diversity (assessed in this study through the number of crops), with crop species having a greater impact. However, to our knowledge, no study has quantified the role of the farming environment in the effect of crop diversity on regulating pest pressure, and limiting the need for pesticides. In this study, we used the classification and regression trees method to identify six clusters of production situations with contrasting levels of pesticide use, taking into account the nature of crop species grown. Our results show that production situations, the crop species, and crop diversity, jointly shaped pesticide reliance at the cropping system level. Specifically, production situations explained 5.6% of the variance in total pesticide use. Crop diversification by adding one extra crop reduced total Treatment Frequency Index by 0.10, after filtering out the influences of production situation, and this effect was significant across all pesticide groups, namely herbicides, fungicides, and insecticides. Our findings provide evidence that increasing crop diversity consistently reduces pesticide reliance across diverse production conditions. These insights highlight the potential of crop diversification as an effective and scalable strategy for sustainable pest management.