Associational effects of Desmodium intercropping on maize resistance and secondary metabolism

Abstract

Abstract Intercropping is drawing increasing attention as a strategy to increase crop yields and manage pest pressure; however the mechanisms of associational resistance remain controversial. We conducted a controlled experiment to assess the impact of co-planting with silverleaf Desmodium (Desmodium uncinatum) on maize secondary metabolism and resistance to herbivory by the spotted stemborer (Chilo partellus). Two maize varieties were grown either with Desmodium or adjacent to it in separate pots. Our findings indicate that co-planting with Desmodium influences secondary metabolism and herbivore resistance through both above and below-ground mechanisms. Stronger effects were generally observed when maize and Desmodium shared the same pot, implying that direct root contact or soil-borne cues play an important role in mediating associational effects on plant resistance in this system.