Every plant shows a distinct behavior at the time of infection. The plant disease can be analyzed by the detailed study of visually observable patterns of a particular plant. The major diseases are pathogens (infectious diseases). A plant scientist is to estimate the damage of plant (leaf, stem) caused due to disease by calculating the percentage of affected area. It results in prejudice and low turnout. In this paper we are going to know the techniques for detection of plant traits or diseases using Image Processing. These techniques are used to decrease the difficulty in detecting the plant diseases. It is any form of signal processing for which the input is an given in the format of image, such as a photograph or video frame and the output of may be either an image or a set of characteristics or parameters related to the image.