Systemic Pesticide Transfer from Treated Corn to Wild Mustard Poses a Risk to Non-Target Herbivores

Modern agriculture frequently uses chemical seed treatments combining fungicides and insecticides to mitigate yield losses caused by pests and pathogens. While effective, these compounds may unintentionally affect non-target organisms. New York State passed Senate Bill S8031, banning prophylactic neonicotinoid use starting in 2029. Diamides, considered less toxic to pollinators, are being considered as alternatives. Our project assesses whether diamide insecticides are a safer by investigating whether non-crop plants can absorb pesticides from treated crops. We predict that a non-target plant, the wild mustard (Rhamphospermum arvvense), will take up pesticides from adjacent treated corn (Zea mays) plant, leading to a higher mortality of caterpillars feeding on wild mustard. We planted wild mustard next to corn seeds treated with the following seed coatings: untreated, fungicide only, fungicide with neonicotinoids, and fungicide with diamides. We calculated the relative growth rate of third star in star larvae of the fall army worm (Spodoptera frugiperda larvae) after feeding on wild mustard leaves for three days. In addition, we collected leaf tissue for LC-MS analysis to determine whether changes in caterpillar growth rate were associated with variations in secondary metabolite profiles. We found that caterpillars feeding on wild mustard leaves from plants growing next to the corn treated with diamide has lower relative growth rate than those fed on wild mustard grown next to the untreated control, fungicide-only, or neonicotinoid and fungicide treated corn. These results indicate potential ecological risks, as systemic insecticides are taken up by non-targeted plants, thereby affecting associated herbivores.

I had the opportunity to work in the Poveda Lab, where I investigated how insecticide seed treatments affect non-target herbivores. Coming into the lab with limited experience in ecology, I improved my statistical analysis skills in R and learned how to think critically about experimental design and data interpretation. With guidance from my mentor, Alexander Chaúta, I gained a deeper understanding of field-based research and working with living systems. Although unexpected results challenged our original goals, they taught me that science requires resilience and adaptability. This experience confirmed my interest for molecular biology and strengthened my motivation to pursue a plant biology PhD with a focus on genome engineering.