What is an appropriate management step for crown gall?

• A. Remove and destroy heavily infected plants
• B. Graft heavily infected plants
• C. Use systemic fungicides early
• D. Plant in shaded areas

Answer: (A)

Crown gall is caused by a bacterial pathogen that survives in plant tissue and in the soil, often entering through wounds. The best way to reduce disease pressure is to remove and destroy heavily infected plants, because this directly lowers the amount of inoculum in the environment and cuts off sources of new infections. Cleaning and sterilizing tools, avoiding wounding, and starting with disease-free or resistant stock are important complementary steps.

Systemic fungicides don’t work against crown gall, since it’s a bacterial disease, not a fungal one. Grafting heavily infected plants can spread the bacteria and create more wound entry points. Planting in shaded areas doesn’t address the bacterial infection and doesn’t reduce the inoculum.