White flies are usually only a problem in green houses, so they say, but I’ve run into many a Texas gardener who begs to differ. There are over 1200 species of whitefly only a few of which are usually a problem in Texas, the silverleaf ( Bemisia argentifolii), banded wing ( Trialeurodes abutiloneus) and the greenhouse (Trialeurodes vaporariorum ).
These insects are very tiny, white and not much bigger than spider mites and have four wings.
You’ll find them in huge quantities underneath leaves when you have them. Eggs are laid under the leaves and the newly hatched crawlers damage the plant by sucking out juice from the plant. Plants will look mottled, really bad cases will yellow the plant and eventually cause its death.
White flies leave a sticky sap on the plant which is then followed by black sooty mold on the top of the plants. Just wash off the sooty mold with soapy water.
Treat with insecticidal oils or insecticidal soaps. The difficulty is that they all fly away as soon as you start to spray. So getting the pesticide to the pest can be a challenge.
They are especially fond of hibiscus, gardenias, and small annuals.