Green Lacewings: Aphid Killer

Controlling insects biologically is challenging because it requires certain detailed knowledge of the target pest, frequent monitoring of the pest populations and anticipatory strategies. That sort of control usually means the application of agricultural chemicals. It is often an instant cure whereas to rely on biological controls alone one must think ahead. One must recognize and anticipate a threatening pest population buildup. Plants can tolerate some pests and the economic threshold should be a consideration. In other words, the dollar gain should exceed the dollar cost.

While there are dozens of beneficial insect predators, most have limited applications, one really stands out as having a multitude of applications – Green Lacewings.

Benefits

• Huge appetite for aphids
• Wide range of other pests attached
• Several generations each season

Limitations

• Only the larva stage is a predator
• Ants can interfere with their attacks on aphids

Despite its beautiful, poetic name, the green lacewing is deadly to almost any soft-bodied insect pest and its eggs. In its adult stage, it lives up to its name, feeding only on nectar and pollen. In its larval stage it’s a voracious consumer of problem insects, known to devour over 200 aphids in a week. They also prey on a wide variety of other soft-bodied insects and mites, including insect eggs, thrips, mealybugs, immature whiteflies and small caterpillars. If it runs out of food, it will cannibalize other lacewing larvae.

Green Lacewing female lay their eggs at the end of long (about 1/4 inch) stalks, presumably to protect them from ants and other lacewing larvae, as they are strongly cannibalistic. Eggs may be laid in a random fashion but is very commonly deposited in a distinctive spiral fashion on leaves or in a straight line on stems.

The larval stage of the Green Lacewing is sometimes confused with the larval stage of Lady Beetles. Larvae of Green Lacewings have spindle-shaped bodies with prominent pincher-like mouthparts and resemble tiny alligators. Larvae of many species of Lady Beetles have spine-like projections and appear to be armored for combat. The armor-like exterior oftentimes has brightly colored flecks.

The sickle-shaped jaws (known as mandibles) of Green Lacewing larvae are used to capture and drain prey of their body fluids. The jaws contain tubes with which they can inject prey with paralyzing venom and then suck out the body fluids.

You can encourage green lacewings to stick around by discontinuing the use of broad-spectrum pesticides. These chemicals often ravage beneficial insect populations, creating room for pest insects to multiply.

Hot to Release

• Release when a few tiny (1/32nd of an inch) larvae are seen moving about the container.
• Gently turn and shake the container to mix the contents.
• Spread the material evenly over the pest infested area.
• A second release, two weeks later, may be necessary.