Control Whiteflies On Gardenia

Q: What is the downside of using diatomaceous earth in your garden, specifically to control whiteflies on gardenia?

A: I don’t know of a downside, except for the fact that it probably won’t control whiteflies on your gardenia. Whiteflies live underneath plant leaves and it’s extremely difficult to get this insecticidal powder under the leaves of your shrubs. If you can figure out a way to spray under the leaves, commercial insecticidal soap (not home-made) will control whiteflies if you are persistent. Otherwise, imidacloprid (Bonide Systemic Granules, Bayer Tree and Shrub, etc) works well. Use it after your shrub blooms to avoid honeybee damage.