Hi Elizabeth - I hesitate to say anything, because you are the expert, but since you asked. ... I'm sure you know it is not only harmful (to all the beneficial insects), but useless to spray poison on them. Whiteflies have already developed resistances to most insecticides. Natural predators of them include ladybugs and lacewings. There is also a tiny non-stinging wasp which parasitizes them and kills them. In the short term, you can buy all these things commercially for release in your garden. In the long term, it is good to be growing flowers in your garden that attract beneficial insects. Insecticidal soap (Safer's or a homemade soapy water solution) and Neem oil work against them. You can also reduce the population, with just a strong blast of water.
Don't over-fertilize your plants (I don't fertilize indoor plants while they are indoors at all). Tender, juicy new growth is most attractive to juice sucking bugs like this and most vulnerable to their attack.
Let us know what you try and what works for you!