Small yellow spots or ringspots, which later become necrotic, appear on the leaves. Pithy tissue in petioles develop necrotic areas that later develop into brown, sunken pits. The virus is transmitted by thrips. No control is known. Aster yellows is caused by a mycoplasma and is transmitted by leafhoppers.
Plants are light yellow in color and stunted.
Petioles become curled, twisted and brittle. Leaves become thickened and brittle. Blackheart is characterized by death of heart leaves which turn black. Softrotting bacteria frequently invade necrotic tissue, causing watery rot. It is a complex physiological disease, but deficiency of calcium in the growing tip is associated with disease.