Whiteflies are tiny insects that feed on the undersides of the leaves of many plants including houseplants, tropicals, and even vegetables. Hibiscus are especially prone to whitefly. Whiteflies are a sucking insect that can damage the leaves by removing too much sap, leading to “stippling” or a pale looking leaf. As their name suggests, this insect is white and can be easily discovered by shaking or brushing against a plant. The adults fly around erratically and are very visible. Whiteflies don’t overwinter outdoors but can be reintroduced to vegetable gardens from tropicals or transplants that are already infected. There are several generations a year. They also produce “honeydew” or their sugary pee which can lead to black sooty mold, further weakening the plant by blocking photosynthesis.
Whiteflies can be controlled by several methods. Low populations are often controlled by beneficial insects such as ladybugs. If populations get large enough to damage plants, Bonide’s “For All Seasons” horticultural oil offers control. It should not be sprayed at high temperatures or on heavily stressed plants, however. Fertilome’s “Indoor/Outdoor” aerosol also offers control.