Unveiling the role of cover crop mixtures: Implications for maize resistance to pests and pathogens

Cover crops have been lauded for their positive ecosystem services, but lately researchers have gained interest on how cover cropping can act as a sustainable pest management tool. Recent findings on how individual cover crops impact plant defenses against multiple pests have encouraged our investigation into how cover crop mixtures can aid in mitigating tradeoffs. For this study, we evaluated Zea mays resistance to fall armyworm (Spodoptera frugiperda) and Fusarium verticillioides after growing in three different soils: soil legacy of a grass cover crop (triticale: xTriticosecale), soil legacy of a brassica cover crop (forage radish: Raphanus sativus), and a mixture of soil from those two crop species. We found evidence that the mixture soil might make corn more susceptible to fall armyworm, yet the outcome might be affected by the length at which soil communities are allowed to settle. The investigation suggests that while cover crop mixtures could potentially impact maize resistance to pests, the duration for which soil communities settle might play a crucial role in determining the outcome for the insect. Also unexpectedly, the cover cropping treatments had minimal effects on maize resistance to F. verticillioides, but there might be reduced maize root growth in mixture and radish soils, contrary to previous studies. In the future, we hope to characterize defensive chemical responses (phytohormones) in each maize treatment, as well as replicate these experiments in a field study.