Impacts of Climate Change on Chinese Cabbage (Brassica rapa) Yields and Damages from Insects

Chinese cabbage (Brassica rapa) is one of the most important fall vegetables in South Korea. Recently, cabbage yields fluctuated due to climate change, leading to an unstable supply and increased prices. Additionally, raised temperatures led to increased beet armyworm (Spodoptera exigua) populations, resulting in greater plant damage. In this study, the Agricultural Policy/Environmental Extender (APEX) model was employed to develop the cabbage growth model. To enhance model accuracy, 4 years of field data collected from multiple locations in South Korea were utilized for model validation and calibration. The model goodness of fit tests revealed R² values between 0.9485 and 0.9873. Two different cabbage models, representing the physiological characteristics of common varieties cultivated in Korea, were applied to assess growth patterns under two distinct climate change scenarios, SSP245 and SSP585. A larval duration prediction model was formulated using previous field data. Under future climate conditions, simulation results indicate that as temperatures rise, Chinese cabbage yields will likely decrease continually, with increasing plant damage from insects. The modeling results can help farmers to control and manage crop insect pests under varying environmental conditions.