Dear experts, my small fig tree developed some little brown dots that then spread to a plumbago and a bougainvillea next to it. It is very bad for leaves as they get all brown and die. It happened last year to the fig tree, but it came back with nice clean leaves this year, only to get all brown again. What do I do? Is there a way to kill this thing?

In case it is relevant, I am in Houston.

Thanks,
Ramiro