Pest profile

Hoplia Beetle

Hoplia callipyge (shown: a Hoplia species) · Coleoptera: Scarabaeidae[2]

Hoplia beetles chew holes in light-colored rose blossoms for a few spring weeks; handpicking is the main remedy, since sprays rarely reach them.[1]

Hoplia beetle, a small scarab with yellowish wing covers and long legs, on a leaf
Hoplia beetle, a small scarab with yellowish wing covers and long legs, on a leaf. (c) katunchik, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adults are oval, about 1/4 inch long, with a reddish-brown head and thorax and silvery-green iridescence in sunlight.[1]
  • Larvae are small, crescent-shaped grubs in the soil.[1]

Look-alikes

Look-alikeHow to tell them apart
Japanese beetleSometimes mistaken for it, but there are no known Japanese beetle populations in California.[1]
Rose chaferOften misidentified as rose chafer, which doesn't occur in California.[1]

Where it lives

It's common in many parts of California, especially the Central Valley.[1]

US map: public records from 1 state since 1990 (GBIF).

Biology and life cycle

Grubs feed on decaying vegetation and roots without harming woody roots, overwintering in the soil.[1]

Adults are active from late March to early May, then return to egg-laying sites; one generation a year.[1]

Damage and signs

  • Adults chew round holes in white, yellow, apricot and pink roses and can ruin early buds; they don't eat leaves.[1]
  • They also feed on calla, citrus, iris, lily, magnolia, peony, poppy and strawberry flowers.[1]

Health risk

It feeds on flowers; UC IPM mentions no risk to people.[1]

Control

Prevention

Where beetles are common, plant darker roses such as reds.[1]

Sprays generally aren't recommended; blossoms shield the beetles and systemics don't reach them in flowers.[1]

Traps and physical control

Pick beetles off or shake them into soapy water regularly, or clip off infested blooms.[1]

White 5-gallon buckets of water with a little detergent may attract and drown some beetles.[1]

Common questions

What's eating holes in my white roses in spring?
In California, hoplia beetles are a likely cause from late March to May.[1]
Should I spray?
Generally no; handpicking works better.[1]

Sources

  1. University of California Statewide IPM Program, “Pest Notes: Hoplia Beetle (Publication 7499).” ipm.ucanr.edu/PMG/PESTNOTES/pn7499.html (accessed 2026-10-06)
  2. iNaturalist, “Hoplia taxon page (order and family).” www.inaturalist.org/taxa/81486 (accessed 2026-10-06)

Updated 2026-10-14. Built from sourced records. Spot an error? Tell us.