Effect of push-pull cropping system and landscape structure on pest control and crop yield

Abstract: Ecological intensification can be used to enhance crop yield while supporting
biodiversity and ecosystem services. Push-pull cropping is a type of ecological intensification
that was developed in East Africa to protect maize from stem borers, and that subsequently was found to also reduce fall armyworm and Striga weeds and to improve soil fertility and crop yield (www.pushpull.net). We, however, still have a poor understanding of when and where push-pull works best. We will examine the influence of landscape composition (e. g., maize cover, grass cover and crop cover) and configuration (e. g., edge density) on pest and weed control, predator abundance and diversity and crop yield. Data was collected in Ethiopia, Kenya, Rwanda, Tanzania, and Uganda. In each country, sixteen pairs of push-pull and nonpush-pull maize and sorghum fields were selected along gradients of landscape level grassland cover and soil type. In each field, we measured the diversity of predators, pest pressure (stem borers and fall armyworm), Striga weeds, leaf damage and crop yield. Data will be analysed using Principal Component Analyses (PCAs) to summarize landscape variables, and Structural Equation Models (SEMs) to evaluate how landscape influences pest and natural enemies’ diversity and abundance and how it cascades down to crop yield.