Practical Manual On Fundamantals Of Plant Pathology: Plant pathogens

All crop plants produced have the potential to become diseased under certain conditions. Diseases of crops can affect yield and/or quality of the harvested commodity. This can impact profitability and increase the risks of farming. A plant is diseased when it is affected by some agent that interferes with its normal development. Some disorders are caused by noninfectious factors, such as temperature extremes or nutrient deficiencies. However, this publication focuses on diseases caused by infectious microorganisms. Diseased plants exhibit a variety of symptoms. These can include stunting, yellowing, wilting, twisting, reddening, browning, blighting, root rot, fruit rot, or other abnormalities. Accurate diagnosis is important in order to effectively control a plant disease. Diagnosis is an art as well as a science, andexperience is important. Until a disease is properly diagnosed, a farmer may waste time and money trying to correct a problem with an unknown cause. Once a disease is diagnosed, appropriate control practices can be selected. Your local Extension agent can provide information on identification and management of crop diseases.