Plant Pathology
Plant pathology is the study of plant diseases that are caused by harmful living things and bad environmental conditions. It looks at how diseases begin, spread, and affect plants, and also how they impact people and animals. It also covers how plants can fight off diseases, how diseases move from one plant to another, and how to stop them from spreading.
Plant Pathogenicity
Plant pathogens are the living things that cause plant diseases. They include fungi, bacteria, viruses, and other small organisms. Most of these pathogens use special enzymes to break down the plant's cell walls so they can get inside. These enzymes often target a substance called pectin. The plant's cell wall helps protect it and is also a food source for some pathogens. These pathogens can grow when the plant's cell walls break down, like during ripening.
Unlike diseases in animals or people, most plant diseases are caused by a single organism, though sometimes more than one is involved.
To detect a plant, pathogens use various tools.
These can include enzymes that help break down the cell wall, harmful chemicals that damage the plant, proteins that help the pathogen take over the plant, hormones that change how the plant grows, and substances that help the pathogen stick to the plant's surface. Some plant problems are not caused by living organisms but by environmental factors like drought, frost, too much water, lack of nutrients, or salt in the soil. These are called non-infectious or abiotic disorders. These can look like diseases caused by pathogens, so it’s important to learn the difference.
Epidemiology
Epidemiology is the study of how diseases spread and why they happen. The disease triangle is a model that says a plant disease needs three things: a host plant, a pathogen, and the right environment. Changing any of these can help control the disease.
Plant Resistance
Plant resistance is the ability of a plant to stop a pathogen from infecting it.
Plants have natural barriers like the cuticle, cell walls, and guard cells. If a pathogen gets through these, the plant uses special signals to create molecules that fight the invader. These signals are controlled by genes, and by changing these genes through breeding, plants can be made more resistant to diseases.
Management
Detection
Managing plant diseases involves finding them early. Old methods looking at leaves and breaking open plant parts, are now used with new techniques like DNA testing. Methods like PCR and LAMP allow scientists to detect diseases more accurately.
Some tools can check for many diseases at once. One of the most commonly used tests is the enzyme-linked immunosorbent assay.
Also read: Plant Cell
Traditional methods
Natural methods, like crop rotation, can help prevent plant diseases. For example, using different crops each year can stop harmful bacteria from building up in the soil. This method has been used for a long time and can be very effective. Plant pathology has been studied for a long time, starting with ancient scholars like Theophrastus. The development of the microscope in the modern era helped scientists understand plant diseases better. The field grew even more in the 19th century.
Some notable people who have contributed to plant pathology include
George Washington Carver, Anton de Bary, Erwin Frink Smith, Agnes Robertson Arber, and Harold Henry Flor.