Crown gall forms soft nodular galls up to one inch in diameter in the region of the graft union. The galls are soft and fall apart easily. Destroy infected plants. No chemical control is listed.
Blight causes ash gray spots on the bud scales and stems. This causes the plant to die back several nodes from the top. The causal organism is Botrytis cinerea and is controlled by benomyl.
Aster yellows may infect plants which should then be destroyed. No chemical control is listed.
Fasciation causes formation of distorted and aborted shoots at soil level. No chemical control is listed.