1. A plant disease, caused by mineral deficiency or a virus or mycoplasma, in which there is yellowing of the foliage. Yellowing is a common symptom when there is a deficiency of elements important in chlorophyll production, namely, iron, magnesium, manganese, nitrogen, or sulphur. Barley yellow dwarf and beet yellows are caused by viruses and coconut lethal yellowing is caused by a mycoplasma. See also deficiency disease
2. A disease of cabbage caused by Fusarium conglutinans.