India's population largely depends on agriculture for their livelihood, making agricultural research vital for the nation's economy. Plant leaf disease diagnosis is essential for ensuring healthy crop production and minimizing financial losses, as plant diseases can significantly reduce crop yield and quality. Machine learning (ML), particularly image-based analysis, has revolutionized plant disease detection. To address plant leaf disease identification via image analysis, a novel KHO-YOLO Net technique has been developed. Contrast Limited Adaptive Histogram Equalization (CLAHE) is applied to plant leaf images to improve their quality. YOLO v8 is used to detect multiple diseases within a single image. YOLOv8 is optimized using the Krill Herd Optimization (KHO) technique for superior classification outcomes. The efficacy of the proposed system is compared to YOLOv3, YOLOv4, YOLOv5, and YOLOv6, with the proposed YOLOv8 demonstrating an overall accuracy improvement to 99.59%.