Loss of root function produces yellowing, wilting, and possibly death of infected plants, especially under stressful growing conditions. Diseased roots lead to stunting and poor growth of plants. Botrytis may also cause a stem blight on cuttings and plants. The Botrytis fungus can colonize dead plant tissues and produce large numbers of spores. Disease control is best done through prevention using a program involving sanitation, cultural control, and chemical fungicides.
Sanitation is important for control of any greenhouse crop disease, and poinsettia is no exception.
Disease-causing fungi and bacteria survive in plant debris from the previous crop, and in soil and water left on floors, benches and equipment. Infectious microbes can also be brought into the greenhouse on contaminated equipment. Clean and disinfest the benches and equipment with a germicide. Transplant rooted cuttings into sterilized soil mix. Regularly collect and remove organic debris such as shed leaves or bracts or declining plants from the greenhouse.