The method involved in the study of plant diseases are as varied as diseases themselves, and only a few of them can be generalized. One can study the specific plant diseases by means of their symptoms, either by naked eye or with the aid of a magnifying glass, while in the field of a particular corp.
Methods involved in the study of plant diseases are as varied as diseases themselves, and only few of them may be generalized. One can study the specific plant diseases by means of their symptoms, studied either by naked eye or with the aid of a hand lens, while in the field of a particular corp. The symptoms of many diseases are more or less same in appearance and sometimes it becomes quite difficult to differentiate a particular disease on the basis of its external symptoms. For a careful study of plant disease, host-parasite interaction should be studied intensively with the aid of a good microscope. For the study of plant disease a basic knowledge of botany in the field of anatomy, taxonomy and physiology are essential.
The identification of a pathogen of a new disease requires the study of its life cycle as well as study of its cultural, physiological and biochemical properties. Such type of study includes the isolation of causal organism from the host, its culturing on the culture media or on green house plants, and its examination under various conditions of nutrition and environment. For doing this one should be familiar with fundamentals procedures of the study of micro organism in the laboratory. This includes the laboratory techniques for handling casual organism, study of their culture and procedures involved in the study of their physiology and biochemistry. In certain plant disease the symptoms are so specific that one can immediately establish its identity by having a glance at it like loose smut of wheat ,rust of wheat may easily be placed in this category. But sometimes it becomes essential to use a hand lens. By using hand lens one can observe entophytic, mycelia, cleistothecia, sclerotia, conidiophores, conidia and others such fruiting bodies and on the basis of the presence of these characteristics structure disease can be identified and confirmed. For example the red rot symptoms appears on the midrib of sugarcane leaf in the shape of specific lesions; if the black dot-dot like acervuli are seen with the aid of hand lens in these lesions test becomes confirmatory. A critical eye is necessary in the study of field symptoms of plant diseases and only through a great deal of experience, such study is possible.