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Silverleaf Whitefly Control Methods

The silverleaf whitefly, also known as the sweet potato whitefly, was first introduced to the United States in 1986 and has become a growing problem since. So much so, it is currently listed on the USDA's National Invasive Species list. ["Invasive Species: Animals - Silverleaf Whitefly (Bemisia argentifolii)", invasivespeciesinfo.gov ] Though they are primarily a concern for large crop producers, they can also affect the home gardener.

Preventative Control Methods

The first line of defense is prevention. The silverleaf whitefly is primarily introduced to the home garden through the purchase of infected plants. Prior to purchasing, carefully inspect your plants for the tell-tale signs of whitefly infestation that include the presence of honeydew or the resulting black, sooty mold, nymphs on the undersides of leaves that may be starting to yellow or dry, or a waxy white substance. ["Whiteflies", imp.ucdavis.edu]

Biological Control Methods

Introducing the silverleaf whitefly's natural predators is a natural, though not always practical method for the home gardener to control the whitefly population. Whiteflies' natural enemies include the ladybug, lacewings, and the Encarsia formosa, a small parasitic wasp. ["Greenhouse:Insects:Whiteflies", ipm.ucdavis.edu]
Reflective mulch also can be used to repel whiteflies. You can use aluminum-coated construction paper or reflective plastic mulch products. ["Whiteflies", imp.ucdavis.edu]

Natural Control Methods

Natural whitefly control methods may be fairly successful for small home garden and houseplant infestations. Since whiteflies are attracted to yellow, yellow sticky strips are effective for smaller populations. Hand vacuuming is another natural control method. You will need to vacuum in the morning when whiteflies are not yet active. In order to kill the whiteflies that have been collected, you will need to empty the vacuum bag into a sealed, plastic bag and place it in the freezer, which will kill them. ["Managing Houseplant Pests", ext.colostate.edu]

Pesticide Control Methods

Whiteflies quickly become immune to pesticides, which is a good argument for attempting methods that will do the least harm to the whitefly's natural predators. Insecticidal soaps and oils, such as neem oil, are best if you opt for this route. ["Whiteflies", imp.ucdavis.edu]