Little White Flies in Dirt
If you see whiteflies on the soil around your plants, it is probably because something disturbed them, causing them to abandon their resting places temporarily. The insects do not fly far. Neither adult whiteflies nor their nymphs tend to spend time in the soil, but adults may land on the soil if they are disturbed. Whiteflies are a problem outdoors during warm weather, but indoors, the pests can survive the winter and continue to trouble your plants. Does this Spark an idea?
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Identification
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Whiteflies are 1/16-inch long, moth-like flying insects. The pests have four wings, and a white wax coating covers their bodies. Adult whiteflies shelter, feed and lay their eggs under plant leaves. One female can lay up to 400 eggs. Newly hatched nymphs crawl around on your plants to find a location to feed. You may never see them because of their extremely small size. Older nymphs may be mistaken for scale insects.
Damage
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Both adults and nymphs feed by drawing sap from plants. Whiteflies collect on and feed from a wide range of plants, including houseplants, flowering plants, vegetable plants and weeds. The pests secrete honeydew, which can lead to sooty mold growth, and whiteflies can transmit viruses to plants. Your plants may appear stressed, and their foliage may yellow and die. Other signs of an infestation include dry, sticky, deformed or silvered leaves.
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Prevention
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Preventing an infestation is the most important step in managing whiteflies, according to the Iowa State University Extension. Inspect all plants before you bring them indoors, and check them regularly afterward for the presence of adults or signs of damage. Keep your plants clean and well-maintained because healthy plants are better able to fight infestations and any subsequent viral infection. Traps can both prevent and treat an infestation by keeping adults from moving onto unaffected plants. Place yellow sticky traps in the area immediately around your plants.
Treatment
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Remove adults by hand, or spray them away with a stream of water. For a small collection of plants and plants with a limited amount of foliage, wipe down the undersides of the leaves. Insecticides are unreliable for treating for whiteflies. The University of Missouri Extension recommends you vary the type of chemical you use, and make weekly applications for at least a month. Neem oil and insecticidal soap are among the insecticides recommended for use against whiteflies.
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References
- Iowa State University Extension; Check Your Houseplants for Whiteflies; Donald R. Lewis; January 2005
- University of Missouri Extension; Managing Whiteflies on Indoor and Outdoor Plants; Bruce A. Barrett; June 2010
- University of Wisconsin Kenosha County Extension; Whiteflies and Houseplants; January 2011
- University of California Davis Integrated Pest Management; Whiteflies; M. L. Flint; September 2002
- University of Florida IFAS Extension, Okaloosa County; Sooty Mold; Larry Williams; 2008
