Leafhopper feeds on China aster and carries aster yellows. Leafhoppers are controlled by one of the following insecticides, carbaryl, Diazinon, methoxychlor, or rotenone.
Aphids suck juices but are controlled by malathion, Diazinon dust, Sevin, or rotenone.
Black blister beetle feeds on flowers and foliage in the middle of June. Sprays of Sevin should control the pest.
Tarnished plant bug punctures the terminal shoot below the flowers and injects a poison causing the flower to die. Tarnished plant bug may be controlled with sprays of Sevin, or malathion.
Mites cause the plants to lose their good green color and appear stippled. Heavy infestations develop noticeable amounts of very fine webbing. Mites are controlled with applications of Diazinon dust.