Tomato (Solanum lycopersicum) production in Nigeria is severely affected by diseases such as bacterial spot, early blight, and yellow leaf curl virus, which reduce yields and impose economic burdens on farmers, ultimately impacting the nation’s agricultural gross domestic product (GDP). Conventional detection methods are often slow, subjective, and error-prone, leading to delayed or ineffective interventions. This study develops a deep learning framework for automated detection and classification of nine common tomato diseases and healthy leaves. The approach integrates transfer learning, ensemble learning, and knowledge distillation to achieve both high accuracy and computational efficiency suitable for mobile deployment. A dataset of 20,245 annotated tomato leaf images was used to train and evaluate five pre-trained Convolutional Neural Networks (ResNet50, EfficientNetB0, MobileNetV2, MobileNetV3-Small, and MobileNetV3-Large). An ensemble of the four best-performing models achieved a test accuracy of 89.86% and a ROC-AUC of 99.19%. Knowledge distillation was then applied, transferring knowledge from ResNet50 to MobileNetV2. The distilled student model retained strong performance, with a validation accuracy above 92% and an F1-score of 0.92, while reducing the model size from 121.81 MB to 108.39 MB. These results demonstrate the potential of the framework to deliver accurate, lightweight, and deployable solutions for plant disease detection, supporting precision agriculture and enhancing food security in Nigeria.
Adesoba et al. (Sun,) studied this question.