The Q&A Archives: Fire Blight on Hibiscus

Question: I live in south Florida and have several hibiscus bushes that seem to have been infected with fire blight. The bark is black (looks scorched), and leaves have withered and crumpled up, turning black before they fall off. One large bush appears to be less infected, and I pruned it back pretty severely. I applied a copper sulfate spray. Is there anything else I can do? Can I be sure it's not anthracnose?
Thank you.

Answer: Fire blight, caused by the bacterium Erwinia amylovora and can infect cotoneaster, flowering crabapple, flowering pear, hawthorn, photinia, pyracantha and mountainash. Hibiscus is generally not affected by it. However, copper-based bactericides are used successfully to control the disease. I think, since you've already pruned out the affected plant parts, your hibiscus stands a pretty good chance of recovering. I'd allow it to regrow and see how it looks.

Anthracnose infected plants generally have a dark streak on the inside wood of cut branches, which makes looking for the streaks a good test in either confirming or ruling out the disease.

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