Many years ago I had a confederate rose that routinely got covered in white flies. Someone told me to top dress the soil with a heavy layer of worm castings, that the "flavor" would be taken up into the plant and the flies would not like it and go away. I tried it and darn if it didn't work. It could have been coincidental but I never had another white fly on that plant. I think if I had container plants in a GH with white flies I might try the castings. It can't hurt and the nutrients they supply are all good.
