Spotted, pale green insects up to 1/8 inch long hop or fly away quickly when a plant is touched. The leaves are stippled and may turn brown.
Apply an insecticide labeled for aster leafhopper, following label directions. Use row covers over the plants to keep leafhoppers out. Eradicate nearby weeds-especially thistles, plantains, and dandelions-which may harbor leafhopper eggs and aster yellows.