The present invention relates to an apparatus, method, software algorithm and system for evaluating plants for conditions or characteristics. In one aspect, the method can include imaging at least a portion of the plant and evaluating the image for discriminating condition(s) or characteristic(s) of interest. In one example, soybean roots are imaged and the image is evaluated to discriminate between soybean cyst nematode (SCN) cysts and the plant roots to count the number of SCN cysts for the plant. In another embodiment, a plant is illuminated by a ultra-violet radiation selected to cause photo-induced fluorescence of a target, e.g. SCN cysts. The fluorescence emitted is collected and analyzed to discriminate between the target and the remainder of the plant.