The common green lacewing, Chrysoperla carnea, is a beneficial insect for gardeners and farmers. Also known as the aphid lion, this species is important for natural pest management. It preys on numerous soft-bodied insects, helping maintain ecosystem balance. This makes Chrysoperla carnea valuable in sustainable agriculture.
Identification and Life Cycle
The life cycle of the common green lacewing involves four distinct stages: egg, larva, pupa, and adult, undergoing complete metamorphosis. Each stage has unique characteristics.
Lacewing eggs are small, oval, and pale green, often turning gray as they develop. They are typically laid individually on slender, hair-like silken stalks, which helps protect them from predators and cannibalism by newly hatched siblings. These eggs are usually found in clusters near pest populations, ensuring a food source for the emerging larvae.
The larval stage is where Chrysoperla carnea earns its “aphid lion” nickname due to its predatory nature. These larvae are active, alligator-like creatures, mottled brown or gray in color, and grow from less than 1 mm to 6-8 mm in length. They possess well-developed legs and large, pincer-like mandibles, which they use to grasp prey and inject digestive enzymes, then suck out the body fluids. This stage typically lasts two to three weeks, during which they consume a large number of pests.
The lacewing enters the pupal phase, forming a spherical, silk cocoon. This cocoon is often found in sheltered spots on plants, such as under leaves or in crevices. The pupation period lasts 10 to 14 days, after which the adult lacewing emerges.
Adult Chrysoperla carnea are typically 12-20 mm long, with slender, pale green bodies and long antennae. Their most recognizable feature is their large, transparent, intricately veined wings, which are held tent-like over their abdomen when at rest. They also have distinctive bright golden or copper-colored eyes, contributing to their common name, “golden eyes”.
A Voracious Predator’s Diet
The dietary habits of Chrysoperla carnea differ between its larval and adult stages, with the larval stage being the primary predatory phase. These “aphid lions” are generalist predators, consuming soft-bodied insect pests. Their aggressive feeding behavior makes them effective in pest management.
Lacewing larvae feed on common garden and agricultural pests. Their diet includes aphids, spider mites, thrips, whiteflies, mealybugs, and leafhoppers. They also consume the eggs of moths and beetles, including cotton bollworm and tobacco budworm. A single lacewing larva can consume 100 to 600 aphids during its two to three-week developmental period, demonstrating their impact on pest populations.
Adult Chrysoperla carnea are not predatory insects. They feed on plant-derived substances such as nectar and pollen. They also consume honeydew, a sugary waste product excreted by aphids, which can attract them to areas with pest infestations. This adult diet supports their energy needs and reproductive capacity, allowing females to lay hundreds of eggs.
Utilizing Green Lacewings for Pest Control
Green lacewings are useful for biological pest control. Their populations can be managed through commercial purchasing or by creating attractive habitats. These methods provide practical ways for gardeners and farmers to leverage their predatory benefits.
Eggs or larvae can be purchased from commercial suppliers. When releasing these beneficial insects, do so during the cooler parts of the day, such as early morning or evening, to minimize stress. Eggs or larvae should be distributed directly onto affected plants, particularly in areas with visible pest activity, or scattered in the crop at rates ranging from 10-100 eggs per square meter.
Attracting adult lacewings naturally is another effective strategy for long-term pest management. Adult Chrysoperla carnea are drawn to flowering plants that provide nectar and pollen. Planting diverse flowers and herbs such as dill, fennel, cosmos, angelica, yarrow, and coreopsis can encourage adults to remain and lay eggs nearby. Providing a nearby water source can also enhance the attractiveness of the habitat.
Avoid broad-spectrum chemical pesticides to ensure lacewing presence and effectiveness. These chemicals can harm lacewings and other beneficial insects, disrupting ecosystem balance and negating biological control benefits. A pesticide-free environment allows lacewings to thrive and contribute to a healthier garden or farm.
Natural Habitat and Distribution
Chrysoperla carnea is a species complex widely distributed across North America, Europe, North Africa, and Asia. Its broad geographic range indicates adaptability to diverse climates and environments. Its widespread presence makes it a globally recognized natural enemy in agricultural systems.
These lacewings inhabit environments where food sources are available. They are commonly found in agricultural fields, meadows, forests, and suburban gardens. Areas with sufficient soft-bodied insect pests for larvae and nectar or pollen sources for adults provide suitable habitat.
During colder periods, Chrysoperla carnea adults overwinter. They seek sheltered locations such as leaf litter, ground cover, or buildings. Their characteristic green coloration changes to a yellowish-brown, providing camouflage and indicating dormancy.