Mealybugs on Outdoor Ornamentals and Citrus

title: "Mealybugs on Outdoor Ornamentals and Citrus"

Mealybugs look distinctive enough that most gardeners recognize them on sight — white, cottony, waxy clusters in leaf axils, on stems, and at root zones. They are most commonly associated with indoor plants, but several species are significant pests in outdoor ornamental gardens and in citrus growing regions.

Per UC IPM, mealybugs are soft-bodied insects in the family Pseudococcidae. They have a wax-covered body and waxy filaments around the margins, giving them their characteristic cottony appearance. Like scale insects, they feed on plant sap with piercing-sucking mouthparts and excrete honeydew that promotes sooty mold.

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Biology

Per UC IPM, mealybugs go through several nymphal stages (instars) before reaching adulthood. Adult females are wingless and continue to feed and produce eggs. Most species produce a cottony egg mass containing 100—200 eggs. Males are winged but short-lived and do not feed.

Mealybugs reproduce rapidly in warm conditions. Outdoors in warm climates, populations can complete multiple generations per year. On Long Island and the Northeast, mealybug populations on outdoor plants typically decline or disappear with the first frost, though root mealybugs can persist in soil.

The primary routes of introduction are infested nursery plants, infested soil, and movement from adjacent infested plants.