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Eucalyptus snout beetle

Gonipterus scutellatus species complex[5]

The eucalyptus snout beetle is an Australian weevil that feeds on eucalyptus leaves. Before biological control it could strip nearly all the leaves from large trees in California, but a tiny egg-parasitic wasp now controls it so completely that the beetle is hard to find there.[1]

Group
Insect
Order
Coleoptera
Family
Curculionidae
US records
2 states
Sources
5 cited
Updated
2026-11-09
Eucalyptus snout beetle, a reddish brown weevil, on a eucalyptus leaf
Eucalyptus snout beetle, a reddish brown weevil, on a eucalyptus leaf. Photo: Andrew J. Crawford, 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 brown and gray, often reddish, weevils about 1/3 inch (7.5 to 8.5 mm) long with a long, tapered snout. From the side the body looks dome-shaped. A dark X-shaped mark on the wing covers is not always visible.[1][2]
  • Larvae are white but look yellowish green because of a sticky coating, with many small black spots and a black stripe along each side. They reach about 2/5 inch and often trail strings of droppings that can stick to the body.[1][2]
  • Eggs are laid in a small, boxlike, blackish to dark brown case about 1/8 inch (3 mm) long, holding rows of yellowish eggs. Eggs turn black when parasitized.[1]
  • Adults notch leaf edges; young larvae scrape pale trails across the leaf surface, and older larvae chew holes right through. Infested foliage looks ragged and scalloped.[1]

Look-alikes

Look-alikeHow to tell them apart
Eucalyptus tortoise beetlesEucalyptus tortoise beetles are two Australian leaf beetles that also chew semicircular holes and notches along eucalyptus leaf edges in California. The snout beetle is a weevil, with a long tapered snout and a dome-shaped body seen from the side, and lays its eggs in small boxlike cases.[4][1]

Where it lives

Native to Australia, where it is a complex of at least eight look-alike species. Members of the complex have spread to New Zealand, South America, California, Hawaii and western Europe.[2][3]

US map: public records from 2 states since 1990 (GBIF).

Biology and life cycle

Adults feed for about a month before laying eggs, and each female can lay several hundred. Eggs hatch in about a week, and larvae pass through four stages while feeding on the leaves.[1]

Mature larvae drop to the ground and pupate in the topsoil; in warm weather adults emerge about a month later. Egg to adult takes 2 to 3 months during the growing season.[1]

Adults fly well and live for several months. They spend the winter clinging to eucalyptus twigs or hiding under loose bark. California has about three generations a year; worldwide the number ranges from one to four, depending on climate and natural enemies.[1][2]

Damage and signs

  • Adults and larvae eat the foliage of various eucalyptus species. Heavy feeding before biological control caused distorted regrowth, dead branches and sometimes dead trees.[1]
  • One of the first signs on infested trees is young foliage that looks scorched and brownish.[2]

Health risk

The sources describe it only as a leaf feeder on eucalyptus; they mention no harm to people.[1][2]

Control

Prevention

No control action is needed. Avoid broad-spectrum, persistent insecticides on eucalyptus, because they can kill natural enemies that keep this and other eucalyptus pests in check.[1]

Biological control

It is completely controlled by Anaphes nitens, a black wasp about 1/25 inch long that lays its eggs inside the beetle's eggs. The same wasp has greatly reduced damage in every country where the beetle has spread.[1][2]

Common questions

Should I spray my eucalyptus for snout beetles?
No. UC IPM says no control action is warranted because the egg parasite controls the beetle completely, and broad-spectrum insecticides can harm the natural enemies of other eucalyptus pests.[1]
What are the small black boxes stuck to my eucalyptus leaves?
They may be eucalyptus snout beetle egg cases. Healthy eggs inside are yellowish; eggs that have turned black were parasitized by the wasp that controls this beetle.[1]

Sources

  1. University of California Statewide IPM Program, “Eucalyptus Snout Beetle (Home and Landscape).” ipm.ucanr.edu/home-and-landscape/eucalyptus-snout-beetle/ (accessed 2026-11-09)
  2. EFSA Journal (European Food Safety Authority), “Pest categorisation of the Gonipterus scutellatus species complex (EFSA Panel on Plant Health 2018, EFSA Journal 16:5107).” pmc.ncbi.nlm.nih.gov/articles/PMC7009585/ (accessed 2026-11-09)
  3. Bulletin of Entomological Research, “Insect pests of eucalypts in California: implications of managing invasive species (Paine and Millar 2002, Bulletin of Entomological Research 92:147-152), abstract.” pubmed.ncbi.nlm.nih.gov/12020373/ (accessed 2026-11-09)
  4. University of California Statewide IPM Program, “Pest Notes: Eucalyptus Tortoise Beetles.” ipm.ucanr.edu/home-and-landscape/eucalyptus-tortoise-beetles/ (accessed 2026-11-09)
  5. iNaturalist, “Gonipterus taxon page (order and family).” www.inaturalist.org/taxa/199384 (accessed 2026-11-09)

Updated 2026-11-09. Built from sourced records. Spot an error? Tell us.