Tiny, Fuzzy and White Plant-Eating Bugs

Mealybugs

• More than 275 mealybug species in the United States belong to the Pseudococcidae and Eriococcidae families. These tiny, oval-shaped insects are less than 1/8 inch long and covered with a waxy coating that often appears fuzzy. Mealybugs are common pests of citrus trees and greenhouse plants. Females lay several hundred eggs on the undersides of leaves. The immature and adult insects suck sap from stems, leaves and roots. They excrete a sticky substance called honeydew that invites mold growth on the plants. Remove mealybug infestations on houseplants with cotton swabs soaked in 70 percent alcohol. Outdoors, predatory insects, especially ladybugs, keep mealybug populations from harming plants. Chemical treatments are necessary for large infestations of this pest on trees.

Woolly Aphids

• Named for the woollike, waxy material covering their body, woolly aphids belong to the insect family Eriosomatidae. They are particular pests of hardwood trees, especially apple. Like mealybugs, woolly aphids feed on plant sap and produce honeydew. Besides attracting mold, honeydew also attracts ants that feed on the sugary excretion. Ladybugs, wasps and other insects control most aphid populations. If jets of water from a hose don’t remove woolly aphids from trees, and there are no signs of predatory insects, chemical insecticides can treat the problem.

Cottony Cushion Scales

• The female cottony cushion scale insect (Icerya purchasi) carries an egg sac on her back that contains several hundred eggs. The egg sac gives the insect its white, fuzzy appearance. Another sap feeder and honeydew producer, this pest damages foliage and affects fruit production of citrus trees. Introducing natural predators of scale insects, such as ladybugs and flies, is an effective biological control measure. Chemical treatment is required only when natural predators are absent.

Whiteflies

• Whiteflies are tiny, winged insects belonging to the family Aleyrodidae. Their wings have a white, powdery covering, giving the insect a fuzzy appearance. This tropical species infests citrus and greenhouse plants and is quite intolerant to cold temperatures. Plant damage from whiteflies includes wilted leaves and mold development. The wasp species Encarsia formosa is a predator of whiteflies and an effective control. Chemical treatment is usually unsuccessful against this pest.