Plant disease is the major threat to the productivity of the plants. Identification of the plant diseases is the key to prevent the losses in the productivity and quality of the yield. It is a very challenging task to identify diseases detection on the plant for sustainable agriculture, where it requires a tremendous amount of work, expertise in the plant disease, and also requires excessive processing time. Hence, image processing is used here for detection of diseases in multi-horticulture plants such as alternaria alternata, anthracnose, bacterial blight, and cercospora leaf spot and also addition with the healthy leaves. In the first stage, the leaf is classified as healthy or unhealthy using the KNN approach. In the second stage, they classify the unhealthy leaf using PNN, SVM, and the KNN approach. The features are like GLCM, Gabor, and color are used for classification purposes. Experimentation is conducted on the authors own dataset of 820 healthy and unhealthy leaves. The experimentation reveals that the fusion approach with PNN and SVM classifier outperforms KNN methods.