Herbaceous landscape ornamentals can succumb to various adverse factors, including infectious and non-infectious diseases. Infectious diseases are caused by microorganisms, such as fungi, fungus-like water molds, bacteria, nematodes, viruses, and phytoplasmas. Abiotic or non-infectious diseases may be attributed to unfavorable growing conditions, which can include nutritional deficiencies, improper soil pH, extreme temperatures, excessive soil moisture, or drought. In order to determine the proper course of action for treatment, it is essential to accurately identify the specific cause(s).