Story by Anita Westervelt, Texas Master Naturalist
Tiny baubles suspended on strings might look odd hanging from leaves in your garden but check them out before you wipe them out, they may be lacewing eggs.
Green lacewings are a beneficial insect with a unique way of laying eggs. The eggs are usually found on vegetation in clusters, lines or spirals with about two dozen or more in a group. Each tiny, light green oval egg is suspended at the tip of a quarter-inch long hair-like filament so fine as to be nearly invisible.
It is thought that this peculiar fashion is to protect the eggs from ants and also from other lacewing larvae which are strongly cannibalistic, according to aggie-horticulture.tamu.edu. The eggs darken as they mature and hatch after about four days.
It is larvae of the lacewing that really benefit a garden. Lacewing larvae are predators; their prey are soft-bodied insect pests such as aphids, thrips, whitefly, leafhoppers, spider mites and mealybugs — all insects that can suck the life out of plants in ornamental and vegetable gardens and field crops. Lacewing larvae devour all stages of their prey — eggs, nymphs and adults.
The larvae look completely different from adult lacewings. The larvae resemble tiny brown alligators about a quarter to nearly an inch long. They have distinct legs on a flat body that tapers to a pointed tail and large, sickle-shaped jaws that can catch and devour prey.
Larvae feed for two to three weeks, spin a cocoon, and then emerge as adults 10 to 14 days later.
There are upwards of 1,300 species of green lacewings found all over the world in temperate and tropical climates. They inhabit agricultural fields, gardens, forests, tropical rainforests, chaparral and swamps.
Adult green lacewings are about three-quarters of an inch long. They have four transparent wings with obvious vein markings which make the wings look lacy. They are a delicate, soft-bodied insect. Adults often fly at night and can be drawn to lights. Most species have large golden eyes.
Adult green lacewings are not predatory; they feed on nectar, pollen and honeydew — honeydew is a sticky, sugar-rich liquid secreted by aphids and some scale insects as they feed on plant sap. Adult green lacewings are minor pollinators. They are active at dawn and dusk laying eggs as they feed. Adult lacewings live four to six weeks.
During summer, a prevalent prey of lacewing larva are mealybugs — garden pests especially during hot, moist weather. Mealybugs attack tropical and subtropical plants, woody trees and shrubs. They can be detected by a white cotton-like substance covering branches, flower buds, fruit and leaves where the bugs are feeding. Mealybugs crawl to nearby plants.
A light infestation of mealybugs can be dislodged from plants with a steady stream of water, a task that may need periodic repeating. Insecticidal soaps and other products can be effective although they will harm beneficial insects like lacewing larvae, as will spraying with water. A severe spread of mealybugs may require heavy pruning, bagging and disposing of infested branches.
Sources helpful in researching for this article include Agrilife.org, Bugguide.net, ScienceDirect.com, gardeninsects.com and Tamu.edu.