PestControlBasics
Menu

Identify

Treat

Local

About

Giant Strong-Nosed Stink Bug

Alcaeorrhynchus grandis[3]

The giant strong-nosed stink bug is a large, speckled brown predatory stink bug that feeds mainly on caterpillars.[1][2]

Group
Insect
Order
Hemiptera
Family
Pentatomidae
US records
9 states
Sources
3 cited
Updated
2026-10-16
Giant strong-nosed stink bug adult feeding on a caterpillar on a leaf
Giant strong-nosed stink bug adult feeding on a caterpillar on a leaf. Photo: Frank Thomas Sautter, public domain (CC0), via iNaturalist
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • Adults are 3/4 to 1 inch long, flat and speckled brown, with a double-pointed spine on each shoulder and a short stabbing beak.[1][2]
  • The wing tips lack speckles and are shinier and veined; the abdomen edges are spotted.[2]
  • Young nymphs are blue-black with red abdomens; older nymphs are blue-black with red keels on the thorax and grow up to about 5/8 inch.[1][2]

Look-alikes

Look-alikeHow to tell them apart
Florida predatory stink bugIts first-stage nymphs are hard to tell from Euthyrhynchus floridanus nymphs; both have blue-black fronts and red abdomens.[1]

Where it lives

Found in the southern United States, south to Mexico, Colombia and Brazil; Florida records cover the whole peninsula.[1]

US map: public records from 9 states since 1990 (GBIF).

Biology and life cycle

Eggs are laid 100 to 200 at a time in masses usually four to five rows wide.[1][2]

Nymphs stay in groups and pass through five stages; in the lab, egg to adult took about 59 to 60 days.[1][2]

Nymphs begin capturing prey in the second stage.[1]

Damage and signs

  • It is generally beneficial: an important predator of soybean pests, found on soybeans, eggplant, shrubs and trees near streams and marshes.[1][2]
  • It has been reported as a pest of eggplant, but crop damage is probably exceptional.[1]

Health risk

None reported to people or pets.[1][2]

Control

Traps and physical control

Usually leave it alone; where it is eating catalpa sphinx caterpillars kept as fish bait, pick the bugs off by hand into soapy water, since insecticides would kill the caterpillars too.[2]

Common questions

Is this big spiny stink bug a pest?
Usually not; it preys on caterpillars and other plant pests.[1][2]
What are the clusters of blue-black and red bugs?
Often giant strong-nosed stink bug nymphs, which stay in groups.[1][2]

Sources

  1. University of Florida IFAS Extension (EDIS, Featured Creatures), “Predatory Stink Bug, Alcaeorrhynchus grandis (EENY-165).” ask.ifas.ufl.edu/publication/IN322 (accessed 2026-10-16)
  2. NC State Extension, “Giant Strong-Nosed Stink Bug (PDIC Factsheet).” content.ces.ncsu.edu/giant-strong-nosed-stink-bug (accessed 2026-10-16)
  3. iNaturalist, “Alcaeorrhynchus grandis taxon page (order and family).” www.inaturalist.org/taxa/296201 (accessed 2026-10-06)

Updated 2026-10-16. Built from sourced records. Spot an error? Tell us.