Answer: Whiteflies can be a real challenge! I've heard that marigolds planted around vegetable gardens repels whiteflies, but further research indicates that marigold roots secrete a substance that is absorbed by nearby vegetables, which repels the insects. I'm not sure you'd get the same effect on your citrus trees. Whiteflies have several natural enemies, including lacewings, bigeyed bugs, minute pirate bugs and a tiny wasp (Encarsia). If you avoid using pesticides in the area, the natural predators will find your population of whiteflies and keep them in check. There appear to be no perennials with the same whitefly repelling qualities as marigolds.
Q&A Library Searching Tips