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Deraeocoris nebulosus (Uhler)
(Heteroptera: Miridae)

by David Boyd, Jr., Urban Entomology Lab, Clemson University, Clemson, SC 29634

Deraeocoris nebulosus (Uhler) is a generalist predator of plant-feeding insects and mites. It is associated with many common pests on more than 50 species of ornamental trees and shrubs (Wheeler et al. 1975). D. nebulosus is found in southern Canada and is widespread in the United States (Henry and Wheeler 1988); it is common in the eastern states (Knight 1941). Reported by Uhler (1876) to be predaceous on a cankerworm, it may have been the first mirid documented as a predator in North America (Wheeler et al. 1975).

Appearance

Adults have ovate, shiny, dark, olive bodies with pale markings, and are 3.5-4.0 mm long and 1.75-2.0 mm wide. The apical half of each forewing is clear with each having a small fuscous dot which helps distinguish D. nebulosus from other species in the genus. Eggs (0.91 mm long, 0.28 mm wide) are laid singly or in groups of two or more in leaf midveins and petioles, with only the operculum, including a respiratory horn, visible (McCaffrey and Horsburgh 1980, Jones and Snodgrass 1998). Nymphs are pale grey, with the early instars having a red tinge and the late instars having red streaks on the legs and a red line between two of the segments on the abdominal dorsum.

Habitat

Deraeocoris nebulosus, collected on more than 75 plant species (Wheeler et al. 1975, Snodgrass et al. 1984), is found in apple orchards (Parrella et al. 1981), peach orchards (Gorsuch et al. 1989), pecan orchards (Mizell and Schiffhauer 1987), cotton fields (Snodgrass 1991) and in landscape plantings (Wheeler et al. 1975).

Pests Attacked (Host Range)

This predator feeds on whiteflies, aphids, psyllids, scales, mites, and lace bugs (Wheeler et al. 1975, pers. obs.). In captivity it tends to cannibalize unless provided with hiding places.

Life Cycle

Adults overwinter in protected places such as under bark. With onset of warmer weather and appearance of new leaves, eggs are laid in the petioles and midveins. This bug has five nymphal stages. Under laboratory conditions, the nymphal period lasts 19.8 days at 21°C (Wheeler et al. 1975) and 13.3 days at 27°C (Jones and Snodgrass 1998). Females have a mean fecundity of about 240 eggs (Jones and Snodgrass 1998). Three generations per year are reported from Pennsylvania (Wheeler et al. 1975), with more suspected farther south. Adults track a succession of plant species, according to prey availability.

Relative Effectiveness

Wheeler et al. (1975) reported that D. nebulosus consumed an average of 107.6 lace bug nymphs during development and 6.9 nymphs per day as an adult. An adult can consume 4-7 cotton aphids per day and 16-19 tobacco budworm eggs per day (Snodgrass 1991). Little work has been done with D. nebulosus in the field.

Conservation

Use of target-specific pesticides only after a pest reaches an economic threshold will help conserve D. nebulosus.

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.

Pesticide Susceptibility

Little work has been done on the susceptibility of D. nebulosus to pesticides. Synthetic pyrethroids show a low toxicity, only up to 10% and 30% susceptible at the low and high rates tested, respectively (Croft and Whalon 1982).

Deraeocoris brevis, a species common in the northwestern United States, is susceptible to many pesticides including azinphosmethly, fenvalerate, diflubenzuron, and organophosphates (Westigard 1973, van de Baan and Croft 1990, Booth and Riedl 1996). D. nebulosus probably is also susceptible to these pesticides.

Commercial Availability

Deraeocoris nebulosus has never been commercially available, though D. brevis was available until early 1998 when it was taken off the market due to labor-intensive rearing methods and decreased demand. Research that is underway to develop mass-rearing methods for D. nebulosus might result in its eventual availability.

Acknowledgments

I would like to thank Drs. A. G. Wheeler, Jr. and P. H. Adler for reviewing earlier versions of this manuscript and for their helpful comments.

References

Booth, S. R. and H. Riedl. 1996. Diflubenzuron-based management of the pear pest complex in commercial orchards of the Hood River Valley in Oregon. J. Econ. Entomol. 89: 621- 630.

Croft, B. A. and M. E. Whalon. 1982. Selective toxicity of pyrethroid insecticides to arthropod natural enemies and pests of agricultural crops. Entomophaga 27: 3-21.

Gorsuch, C. S., G. T. Lee, and D. R. Alverson. 1989. Arthropod species collected from peach trees in South Carolina utilizing a whole-tree sampling method. J. Agric. Entomol. 6: 233-255.

Henry, T. J. and A. G. Wheeler, Jr. 1988. Family Miridae Hahn, 1833 (=Capsidae Burmeister, 1835), pp. 251-507. In T. J. Henry and R. C. Froeschner [eds.], Catalog of the Heteroptera, or true bugs, of Canada and the continental United States. Brill, New York.

Jones, W. A. and G. L. Snodgrass. 1998. Development and fecundity of Deraeocoris nebulosus (Heteroptera: Miridae) on Bemisia argentifolii (Homoptera: Aleyrodidae). Fla. Entomol. 81: 345-350.

Knight, H. H. 1941. The plant bugs, or Miridae, of Illinois. Bull. Ill. Nat. Hist. Surv. 22: 1-234.

McCaffrey, J. P. and R. L. Horsburgh. 1980. The egg and oviposition site of Deraeocoris nebulosus (Hemiptera: Miridae) on apple trees. Can. Entomol. 112: 527-528.

Mizell, R. F. III and D. E. Schiffhauer. 1987. Trunk traps and overwintering predators in pecan orchards: Survey of species and emergence times. Fla. Entomol. 70: 238-244.

Parella, M. P., J. P. McCaffrey, and R. L. Horsburgh. 1981. Population trends of selected phytophagous arthropods and predators under different pesticide programs in Virginia apple orchards. J. Econ. Entomol. 74: 492-498.

Snodgrass, G. L. 1991. Deraecoris (sic) nebulosus (Heteroptera: Miridae): Little known predator in cotton in the Mississippi Delta. Fla. Entomol. 74: 340-344.

Snodgrass, G. L., T. J. Henry, and W. P. Scott. 1984. An annotated list of the Miridae (Heteroptera) found in the Yazoo-Mississippi Delta and associated areas in Arkansas and Louisiana. Proc. Entomol. Soc. Wash. 86: 845-860.

Uhler, P. R. 1876. List of Hemiptera of the region west of the Mississippi River, including those collected during the Hayden explorations of 1873. In Bull. Geol. Geogr. Surv. Terr. 1. Pp. 267-361.

van de Baan, H. E. and B. A. Croft. 1990. Factors influencing insecticide resistance in Psylla pyricola (Homoptera: Psyllidae) and susceptibility in the predator Deraeocoris brevis (Heteroptera: Miridae). Environ. Entomol. 19: 1223-1228.

Westigard, P. H. 1973. The biology of and effect of pesticides on Deraeocoris brevis piceatus (Heteroptera: Miridae). Can. Entomol. 105: 1105-1111.

Wheeler, A.G., Jr., B. R. Stinner, and T. J. Henry. 1975. Biology and nymphal stages of Deraeocoris nebulosus (Hemiptera: Miridae), a predator of arthropod pests on ornamentals. Ann. Entomol. Soc. Am. 68: 1063-1068.

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