Continuous monitoring of soybean (Glycine max) electrical signaling during stink bug (Euschistus heros) infestation and plant protection measures

Stink bug feeding on soybean pods requires vigilant crop protection due to low economic thresholds. This study used extracellular plant electrophysiology (EPE) to continuously monitor plant electrical signals (ES) during infestation. Greenhouse experiments evaluated crop infestation scenarios with the insecticide Verdavis (isocycloseram and lambda-cyhalothrin). Plant ES were recorded for different infestation periods, and related crop damage was compared with EPE output. Based on these experiments, an EPE model was developed to quantify spike occurrences. Distinct spike counts emerged within the first day of infestation: infested plants with visual damage after 7 days generated significantly more ES spikes compared to non-infested controls (p < 0.001). Conversely, plants that showed only marginal damage after 7 days did not exhibit significant differences in ES spike generation (p = 0.058). Treated plants generated similar spike patterns as non-infested plants, indicating effective plant protection. Manual insect removal led to rapid reduction of spike count. Additionally, more spikes were recorded during the day (p < 0.001), but spike output was similar between pod- and stem-inserted electrodes during day (p = 0.837) and night (p = 0.328). This study demonstrates that EPE can be used as a minimally invasive method for real-time monitoring of plant protection, providing insights into plant-insect interactions and insect control measures.