Plant disease and stress detection is a crucial agricultural competence. This approach generally uses time-consuming, insufficient visual examination. To help, AI-based apps diagnose plant illnesses. Many methods for identifying plant diseases are laborious, involve expert personnel, and require a lab. New optical sensors use electromagnetic spectrum to detect plant stressors and provide precise information. This includes identifying black spot, leaf spot, and mildew. Environmental elements including light, temperature, water, humidity, and nutrition are considered to detect environmental stress-related plant diseases. Automatic disease detection and categorisation can detect symptoms early, minimising big farm monitoring labour. Leaf spots, blight, chlorosis, necrosis, and wilt are plant disease symptoms. Sustainable agriculture requires effective, cheap, and eco-friendly plant disease control.