A tropical evergreen shrub with glossy green leaves, schefflera (Schefflera spp.) is a fast-growing plant most often grown indoors. However, in warm climates, schefflera grows outdoors, where it reaches a height of up to 40 feet. Although hardiness varies depending on the species, most grow in U.S. Department of Agriculture plant hardiness zones 9b through 11. Schefflera is relatively easy to grow, but the plant is sometimes affected by a variety of common pests. When applying any type of insecticidal product, always read the product label for warnings on toxicity and keep children and pets away from the treated area. Wear protective clothing when mixing and applying, if necessary.
Mites, a common enemy of ornamental plants, are not true insects but tiny arachnids related to ticks and spiders. The tiny pests live in colonies, often on the underside of leaves. If the pests are too tiny to see with the naked eye, you can usually recognize the fine, silky webbing and tiny dots, or stippling that they leave on leaves. In small numbers, the pests aren't usually problematic. However, in large numbers, the pests cause leaves to turn bronze or yellow before they drop from the plant. Don't spray mites with pesticides because the sprays kill many beneficial insects that prey on mites. Insecticidal soaps or horticultural oils are less harmful options.
Insects that suck the juices from the leaves of a schefflera plant include aphids, thrips and scale. Insecticidal soap sprays are effective, relatively safe treatments. You can make your own insecticidal soap spray by mixing 1 tablespoon of liquid dish detergent in 1 quart of water. However, homemade solutions are sometimes harsh and may damage the plant. Commercial soap sprays are readily available in both pre-mixed and concentrated form. If you choose a concentrated product, mix the soap at a rate of 1 to 4 teaspoons per quart of water, depending on the severity of the infestation. Spray both sides of the leaves. Repeat every four to seven days, if needed.
One of the most common enemies of ornamental plants, mealybugs are easy to spot by the protective cottony, mealy masses on the joints and undersides of leaves. Light infestations are relatively easy to remove by dabbing the pests with a cotton swab dipped in rubbing alcohol. Repeat as needed until the pests are eradicated. Spray the pests with insecticidal soap if the infestation is heavy. In some cases, the best treatment is to prune and discard affected branches.
Caterpillars sometimes affect schefflera plants grown outdoors. Because of their size, the pests are easy to spot. If the numbers aren't great, you can pick the pests off by hand. If you notice egg masses on the plant's trunk, remove them by scraping the masses into a container of soapy water. If the infestation is heavy, you can spray the pests with a product containing Bacillus thuringiensis (Bt). When caterpillars eat the natural bacteria, they usually die within two to three days.