“…In addition, traditional approaches to disease classification via machine learning typically focus on a small number of classes usually within a single crop. Examples include a feature extraction and classification pipeline using thermal and stereo images in order to classify tomato powdery mildew against healthy tomato leaves (Raza et al, 2015 ); the detection of powdery mildew in uncontrolled environments using RGB images (Hernández-Rabadán et al, 2014 ); the use of RGBD images for detection of apple scab (Chéné et al, 2012 ) the use of fluorescence imaging spectroscopy for detection of citrus huanglongbing (Wetterich et al, 2012 ) the detection of citrus huanglongbing using near infrared spectral patterns (Sankaran et al, 2011 ) and aircraft-based sensors (Garcia-Ruiz et al, 2013 ) the detection of tomato yellow leaf curl virus by using a set of classic feature extraction steps, followed by classification using a support vector machines pipeline (Mokhtar et al, 2015 ), and many others. A very recent review on the use of machine learning on plant phenotyping (Singh et al, 2015 ) extensively discusses the work in this domain.…”