Abstract:Accurate identification of pepper diseases and pests in complex field environments remains challenging due to dense target distributions, significant scale variations, and practical deployment constraints of existing detection models. To address these issues, PDPI?YOLO, a efficient detection model was proposed based on an enhanced YOLO 11n architecture. Firstly, the model reconstructed the feature extraction structure using MobileNetV4 as the backbone, leveraging its efficient inverted residual blocks and integrated attention mechanisms to enhance multi?scale feature representation. Secondly, the original SPPF module in the backbone was replaced by the SPPF_LSKA feature enhancement module. By integrating the large kernel attention (LSKA) mechanism, this module augmented global contextual information at the end of the backbone, providing superior top?level semantic inputs for the feature pyramid and thereby optimizing the efficacy of feature fusion within the pyramid structure. Furthermore, a dynamic upsampling operator (Dysample) was incorporated into the feature fusion process to adaptively enhance multi?level feature integration and localization accuracy. Finally, the EfficientHead optimized the detection head structure, ensuring high precision while handling dense and scale?varying targets. Experiments on a public Kaggle dataset of six common pepper diseases and pests showed that PDPI?YOLO achieved a precision of 80.8%, recall of 75.7%, mAP50 of 83.1%, and mAP50-95 of 43.5%, outperforming the baseline by 5.6, 1.7, 3.8, and 1.2 percentage points, respectively. When deployed in a visual interface, the model achieved inference times under 0.1 s per image, meeting real?time requirements. Validation on a self?built dataset of Dongshan smooth?skinned pepper further confirmed its generalization capability and robustness, with inference times below 0.2 s per image. This model can offer practical technical support for automated disease and pest monitoring systems and intelligent plant protection equipment in edge environments.