Diagnosis of Fungal and Bacterial Diseases Based on Symptom & Sign

Abstract

Plant disease diagnosis is a form of hypothesis testing, where the hypothesis is simply the identity of the disease, and a good diagnostician goes through multiple iterations of the scientific method (seeking evidence through testing that supports or refutes the hypothesis that s/he generates). Identification of affected plants is one of the first steps in diagnosing a plant disease. Diagnosis is one of the most important aspects of a plant pathologist's training. Both scientific and common names of the plant should be noted. Without proper identification of the disease and the disease-causing agent, disease control measures can be a waste of time and money and can lead to further plant losses. Fungi are small, generally microscopic, eukaryotic, usually filamentous, branched, spore-bearing organisms that lack chlorophyll. Bacteria are prokaryotes. These are generally single-celled microorganisms whose genetic material (DNA) is not bound by a membrane and therefore is not organized into a nucleus. Our general objective was to acquaintance with Plant pathology laboratory materials & make disease diagnosis from field up to laboratory based on symptom and signs from different plant samples. All most all necro-tropic and bio-tropic fungi are grown on PDA agar, but bio-tropic fungi and bacterial diseases cannot grow on PDA agar. The best preferable method to diagnosis bio-tropic fungi is using direct leaf assay and blotting method on petri-dish. For bacterial disease identification we use NA agar. From this laboratory work I had concluded that those fungal and bacterial diseases need their niche to grow and well identified. It is very difficult to identify plant diseases based on sign and symptom. It is very imperative to diagnosis plant disease by collaborating both conventional (using sign and symptom) and molecular methods. It needs further work to identify rust diseases using race analysis up to f. species level.