Cornell University, Biological Control: A Guide to Natural Enemies in North America


Geocoris pallens adult. R.Bugg

Geocoris spp.
(Heteroptera: Lygaeidae)

Bigeyed Bug

by James Hagler, USDA-ARS, Western Cotton Research Laboratory, Phoenix, AZ 85040-8830

Bigeyed bugs, Geocoris spp., are among the most abundant and important predaceous insects in many cropping systems in the U.S. There are approximately 19 species that inhabit North America. Of these, G. punctipes and G. pallens are the most common. Geocoris spp. are known to feed on plants, however they rarely cause economic damage.

The most common species found in North America are:

  • G. punctipes
  • G. pallens
  • G. bullatus
  • G. uliginosus

Appearance

Adults and nymphs have oval bodies and broad heads. Their most distinguishing characteristic is their large, bulging eyes. They have relatively short antennae that are slightly enlarged at the tip. Bigeyed bugs walk with a distinctive "waggle" and omit a fowl odor when handled. Adults are about 3/16th inch long and silver/gray in appearance (G. punctipes). The immatures look like small adults, but lack fully developed wings. "Hot dog" shaped eggs are laid singly on leaves and stems of many crops. They are white to tan with a distinctive red spot. Both the adults and immatures feed by sucking juices from their prey through a "needle-like" beak.

Beware: chinch bugs, a pest of turfgrass, resemble bigeyed bugs and managers sometimes mistakenly spray when the biological control agent is found.

Habitat

Geocoris spp. are commonly found throughout the southern regions of the U.S. in most cropping systems. G. punctipes and G. pallens are the most common species along the cotton belt.


Bigeyed bug eggs. Note the distinctive red spot. S.Naranjo


Bigeyed bug nymph feeding on corn earworm egg. J.K.Clark
Courtesy of the Univ. of Calif. Statewide IPM Project


Bigeyed bug adult. C.Pickett

Pests Attacked

Bigeyed bugs feed on a wide variety of prey smaller than themselves. They are among the most important natural enemies in cotton. They feed on eggs and small larvae of most lepidopteran pests (bollworm, pink bollworm, tobacco budworm), on the eggs and nymphs of plant bugs (e.g., lygus), and on all life stages of whiteflies, mites and aphids.

Life Cycle

Bigeyed bugs overwinter as adults. As with any insects, their life cycle will depend on temperature. Eggs that are laid singly on leaves or stems hatch in approximately one week. Bigeyed bugs have five nymphal instars, each of which lasts from 4 to 6 days. Adults live approximately one month and a female can lay up to 300 eggs during her adult life span. Several generations may occur during a crop growing season.

Relative Effectiveness

The potential for Geocoris spp. as biological controls is well founded. Adults and immatures can consume dozens of prey per day (Hagler & Cohen, 1991). However, due to the small size and cryptic nature of this beneficial, quantification of predation in the field is difficult (Hagler & Naranjo, 1994). For a detailed discussion on the difficulties of quantifying predation, visit James Hagler's Predator Biology Laboratory.

Conservation

Geocoris spp. are ideal candidates for conservation. Since bigeyed bugs are also seed feeders, refuge crops can be planted that harbor large populations of Geocoris. For example, Tamaki and Weeks (1972) investigated the possibility of increasing bigeyed bug populations in crop lands by planting sunflowers. Their results were very encouraging. Exploiting the potential of Geocoris spp. as a native biological control agent deserves further study.

Polycropping, use of pest-specific insecticides (e.g., microbials, insect growth regulators, Bt cotton, etc.), and use of economic thresholds to minimize pesticide applications are all practical recommendations for preserving Geocoris (and other natural enemies) populations.
Geocoris adult among disk flowers of sunflower. C.Pickett

Pesticide Susceptibility

As with most beneficial insects, Geocoris spp. are very susceptible to broad spectrum pesticides. Conservation of bigeyed bugs and the use of broad spectrum pesticides are not compatible.

Commercial Availability

Available through Entomos, LLC (info@entomos.com), 4445 SW 35th Terrace, Suite 310 Gainesville, Florida 32608, 352-371-6490. However there is enormous potential for mass producing G. punctipes in the near future for augmentative biological control programs. The first artificial diet for rearing any insect predator was developed for G. punctipes (Cohen, 1985). If this diet can be automated and mass-produced, then G. punctipes might become commercially available.

References

    Cohen, A.C. 1985. A simple method for rearing the insect predator Geocoris punctipes on a meat diet. J. Econ. Entomol. 7: 1173-1175.

    Hagler, J.R. & A.C. Cohen. 1991. Prey selection by in vitro- and field-reared Geocoris punctipes. Entomol. Exp. Appl. 59: 201-205.

    Hagler, J.R. & S.E. Naranjo. 1994. Determining the frequency of heteropteran predation on sweetpotato whitefly and pink bollworm using multiple ELISAs.

    Mengersen, E. 1997. Personal communication.

    Tamaki, G. & R.E. Weeks. 1972. Efficiency of three predators, Geocoris bullatus, Nabis americoferus and Cocinella transversogutata, used alone or in combination against three insect prey species, Myzus persicae, Ceramica picta, and Manastra configurata, in a greenhouse study. Environ. Entomol. 1: 258-263.

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