Biological Control : A Guide to Natural Enemies in North America Anthony Shelton, Ph.D., Professor of Entomology, Cornell University
 

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Chrysoperla (=Chrysopa) carnea, C. rufilabris
(Neuroptera: Chrysopidae)
Common Green Lacewing (=C. carnea)

These green lacewings are common in much of North America. Adults feed only on nectar, pollen, and aphid honeydew, but their larvae are active predators. C. carnea occurs in a wide range of habitats in northeastern, midwestern and western U.S., and C. rufilabris may be more useful in areas where humidity tends to be high (greenhouses, irrigated crops, southeastern and midwestern U.S.).

Appearance

Adult green lacewings are pale green, about 12-20 mm long, with long antennae and bright, golden eyes. They have large, transparent, pale green wings and a delicate body. Adults are active fliers, particularly during the evening and night and have a characteristic, fluttering flight. Oval shaped eggs are laid singly at the end of long silken stalks and are pale green, turning gray in several days. The larvae, which are very active, are gray or brownish and alligator-like with well-developed legs and large pincers with which they suck the body fluids from prey. Larvae grow from <1 mm to 6-8 mm.

Habitat (Crops)

Cotton, sweet corn, potatoes, cole crops, tomatoes, peppers, eggplants, asparagus, leafy greens, apples, strawberries, and other crops infested by aphids.

Pests Attacked

Several species of aphids, spider mites (especially red mites), thrips, whiteflies, eggs of leafhoppers, moths, and leafminers, small caterpillars, beetle larvae, and the tobacco budworm are reported prey. They are considered an important predator of long-tailed mealybug in greenhouses and interior plantscapes.

Life Cycle

These two species of green lacewings overwinter as adults, usually in leaf litter at the edge of fields. During the spring and summer, females lay several hundred small (<1 mm) eggs on leaves or twigs in the vicinity of prey. Larvae emerge in 3-6 days.

Green Lacewing Life Cycle

The larval stage has three instars and lasts two to three weeks. Mature third instars spin round, parchment-like, silken cocoons usually in hidden places on plants. Emergence of the adults occurs in 10 to 14 days. The life cycle (under 4 weeks in summer conditions) is heavily influenced by temperature. There may be two to several generations per year.

Relative Effectiveness

These lacewing larvae are considered generalist beneficials but are best known as aphid predators. The larvae are sometimes called aphid lions, and have been reported to eat between 100 and 600 aphids each, although they may have difficulty finding prey in crops with hairy or sticky leaves.

Natural populations of Chrysoperla have been recorded as important aphid predators in potatoes, but mass releases of lacewings have yet to be evaluated against aphids in commercial potato production. In small scale experiments outside the United States, lacewings achieved various levels of control of aphids on pepper, potato, tomato, and eggplant, and have been used against Colorado potato beetle on potato and eggplant. On corn, peas, cabbage, and apples, some degree of aphid control was obtained but only with large numbers of lacewings. Mass releases of C. carnea in a Texas cotton field trial reduced bollworm infestation by 96%, although more recent studies show that C. carnea predation on other predators can disrupt cotton aphid control.

C. carnea is considered an important aphid predator in Russian and Egyptian cotton crops, German sugar beets, and European vineyards. The North Carolina State University Center for IPM considers it an important natural enemy of long-tailed mealybug, one of the 5 most important pests of NC interiorscapes.

Several strains of C. carnea occur in North America. Matching of the proper strain to specific pest management situations is desirable.

Pesticide Susceptibility

C. carnea appears to have some natural tolerance to several chemical insecticides although there may be considerable variation. Populations tolerant of pyrethroids, organophosphates, and carbaryl have been selected in the laboratory.

Conservation

Because young larvae are susceptible to dessication, they may need a source of moisture. Adult lacewings need nectar or honeydew as food before egg laying and they also feed on pollen. Therefore, plantings should include flowering plants, and a low level of aphids should be tolerated. Artificial foods and honeydew substitutes are available commercially and have been used to enhance the number and activity of adult lacewings. These products may provide sufficient nutrients to promote egg laying, but they cannot counter the dispersal behavior of newly emerged adult lacewings.

For general information about conservation of natural enemies, see Conservation in the Tutorial section on this site, Feature Article on conservation in Volume II, No. 1 of Midwest Biological Control News.

Commercial Availability

C. carnea and C. rufilabris are available commercially (see the off-site publication, Suppliers of Beneficial Organisms in North America, page of the California Department of Pesticide Regulation website), and are shipped as eggs, young larvae, pupae, and adults. C. carnea is recommended for dry areas, C. rufilabris for humid areas. Larvae are likely to remain near the release site if aphids or other prey are available. Newly emerging adults, however, will disperse in search of food, often over great distances, before laying eggs.

Acknowledgments

Thanks to Maurice J. Tauber and Catherine A. Tauber, Department of Entomology, Cornell University, for their help in reviewing and for offering suggestions that improved this section.

References

Henn, T., and Weinzierl, R. (1990) Alternatives in insect pest management. Beneficial insects and mites. University of Illinois, Circular 1298. 24 pp.

Hoffmann, M.P. and Frodsham, A.C. (1993) Natural Enemies of Vegetable Insect Pests. Cooperative Extension, Cornell University, Ithaca, NY. 63 pp.

Pree, D.J., Archibald, D.E., Morrison, R.K. (1989) Resistance to insecticide of the common green lacewing (Chrysoperla carnea (Neuroptera: Chrysopidae) in southern Ontario. J. Econ. Ent., 82: 29-34.

Rincon-Vitova Insectaries, Inc. (1974) Leaflet on Chrysopa carnea. Quoted in: Biological Control By Natural Enemies, by P. DeBach. Cambridge University Press, Cambridge, England. 323 pp.

Rosenheim, J.A., and Wilhoit, L.R. (1993) Predators that eat other predators disrupt cotton aphid control. Cal. Agricul., 47: 7-9.

Tauber, M.J. and Tauber, C.A. (1983) Life history traits of Chrysopa carnea and Chrysopa rufilabris (Neuroptera: Chrysopidae): influence of humidity. Ann. Entomol. Soc. Am. 76: 282-285.

Tauber, M.J. and Tauber, C.A. (1993). Adaptations to temporal variation in habitats: categorizing, predicting, and influencing their evolution in agroecosystems In: Evolution of Insect Pests (K.C. Kim & B.A. McPheron, Eds.), pp.103-127. John Wiley & Sons, NY.

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Green lacewing egg

Larva eating aphid

Top: Green lacewing egg

Bottom: Larva eating aphid
Photos: J.K. Clark, University of
California Statewide IPM Project


Green lacewing pupa

Adult green lacewing, Chrysopa oculata

Top: Green lacewing pupa

Bottom: Adult green lacewing, Chrysopa oculata
Photos: J. Ogrodnick

   
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