Wheat intraspecific diversity suppressed diseases with subdued yield, economic return and arthropod predation services

The push for sustainable intensification requires development of alternative strategies for managing crop production that improve yields while maintaining or enhancing environmental services. We propose that intraspecific mixtures potentially exploit landscape ecosystem services to help suppress pests, impede disease spread, and ultimately improve yields. To test this hypothesis, we conducted a three-year field study of wheat cultivar mixtures compared to sole cultivar stands and evaluated pest control, yield, and economic benefits. Arthropod pests were not abundant in our experiment and predator abundance varied unpredictably across mixtures and sole cultivar stands. We found that mixtures suppressed foliar diseases at a level comparable to that of a fungicide application but had less impact on head diseases. Yield and economic return over variable costs were similar for mixtures and sole cultivar stands (3875 vs 3817 Mg ha⁻¹ of wheat, $473 vs $462 ha⁻¹, respectively), indicating that mixtures may provide similar yields and economic returns. In the three years of this project, there was no substantial benefit of using mixtures, but neither was there a penalty, indicating that planting mixtures can minimize risks should insect pests or disease outbreak.