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Hannah Mathers, The Ohio State University, Horticulture and Crop Science |
Nurseries that produce high-quality nursery stock usually have a strong nursery monitoring program in place. One important part of a nursery monitoring program is to know how to submit a good sample for outside consultations and/or confirmations. When you submit samples to a plant diagnostic laboratory, the expected outcome is a confirmation or refutation of the presence of an infectious disease. Infectious diseases are often referred to as biotic disorders, meaning the causal organism is alive. Sixty percent or more, however, of what is presented to most diagnostic laboratories is abiotic in origin. Abiotic means the causal organism is not alive.
Being able to determine the difference between abiotic disorders and biotic infections in the field is not always easy. Sometimes submitting a sample to the diagnostic laboratory is a good idea even when you are quite sure the primary cause of the problem is abiotic. In some situations, secondary pathogenic invaders may come in after an abiotic injury, and you may want to ensure that you're not missing something that will cause problems later.
Some common non-infectious or abiotic disorders are physiological disorders like graft incompatibility, chemical injuries due to pesticide applications, nutritional deficiencies or excesses, excess light or shading, planting problems, flooding, drought, or salt damage. Mechanical injury due to wind, ice, or other physical factors such as mowers or pollution injuries are also common abiotic problems. Temperature extremes, either too high or too low, are a predominant cause of container abiotic injuries.