Know You Pests and Recognize Their Enemies: Lacewings

While scouting for pests or during field walks with growers I often see more beneficial insects than pests. One of the more underappreciated groups of beneficial insects is green lacewings.  Despite their fragile appearance, green lacewings are valuable natural enemies of insect pests in the field, attacking many types of soft-bodied insects and insect eggs. Natural enemies of crop pests help to slow the rate at which pest populations build in numbers, much of the time preventing them from reaching an economic injury level.

Figure 1. The numerous cross veins in the wings give lacewings their common name. (Photo: Ric Bessin, UK)

Figure 1. The numerous cross veins in the wings give lacewings their common name. (Photo: Ric Bessin, UK)

Green lacewings are weak fliers and are commonly found near aphid colonies or other insect prey. They are almost an inch long, green in color, and have two hemispherical golden eyes. They get their name from the lace-like appearance of their wings due to the numerous cross veins. As adults, some species feed mostly on nectar, pollen, and honeydew, but other species feed on insects. The egg stage is quite different from other insect eggs; each lacewing egg is perched on a ½-inch hair-like stalk. Larvae are voracious predators and are often called aphid lions. They are brown and white and may grow up to about ½ inch in length. The larval stage is the most beneficial stage; larvae feed on soft-bodied insects like aphids, but will also feed on caterpillars and some beetles.

Figure 2. Lacewing larvae feed with long sickle-shaped mandibles. (Photo: Ric Bessin, UK)

Figure 2. Lacewing larvae feed with long sickle-shaped mandibles. (Photo: Ric Bessin, UK)

Lacewings can be purchased commercially either as eggs or larvae.  Releasing either of these stages has the benefit that they will not move far to find prey, unlike what might happen when winged adults are released.

 

Ric Bessin, Extension Entomologist

 

Posted in Vegetables