Hello,

Thank you for contacting Ask Extension. Is it possible to get a picture of the actual fly that is infesting the hibiscus? Less than 8mb would be able to be downloaded. he closer and clearer the picture, the better we can identify it and give you help.

Thank you for contacting Ask Extension.

White flies appear to like shaded areas, so if it is possible, then move the plant into full sun. Leaf removal is most effective when populations are restricted to a few plants or leaves. It is important to constantly monitor the plants if you are going to manage whiteflies. Place infested plant materials in plastic bags, seal and throw them away. Efficacy of leaf removal will vary among plant species. While giant whitefly may currently be found on many different plant species, suitability of these plants as reproductive hosts varies. On less preferred hosts, such as yellow hibiscus, removal of leaves should be sufficient to control populations. On more preferred host plants, such as red hibiscus control will require early detection, rigorous leaf removal, and spraying the plant with water.

The most effective way to get rid of white flies is to use a strong stream of water directed to the undersides of infested leaves, at least once a week. This will get rid of larva and nymphs during the process. There is a biological control, which I have included a brochure from UC for the types of biological control. Giant Whitefly Management Guidelines--UC IPM (ucanr.edu)

Insecticides are not recommended because they kill biological control agents. Since this is for California, I cannot recommend any chemical to use, because we are unaware of what is available.

White Flies – Southern California Hibiscus Society (socalhibiscussociety.org)

I have also included the contact information for asking questions To UC Master Gardener Program. https://mg.ucanr.edu/FindUs/