Pest profile

Spider Mite Destroyer

Stethorus species (S. punctum in the East, S. picipes in California) · Coleoptera: Coccinellidae[3]

Barely 1/16 inch long, the spider mite destroyer is a lady beetle that eats nothing but plant-feeding mites, and it homes in on mite outbreaks.[1][2]

Tiny black spider mite destroyer lady beetle covered in fine pale hairs on a leaf, next to a 1 mm scale bar
Tiny black spider mite destroyer lady beetle covered in fine pale hairs on a leaf, next to a 1 mm scale bar. Photo: Jesse Rorabaugh, public domain (CC0), via iNaturalist

How to identify it

  • Adults are black, oval and domed, about 1/16 inch (1.5 mm) long, and look grayish because of fine pale hairs.[1][2]
  • Young larvae are dark gray with many tiny branched hairs, and they turn reddish from the edges inward as they mature.[1][2]
  • Eggs are pale, oval and tiny, laid singly on their sides, mostly beside the main veins under leaves.[1][2]
  • Newly emerged adults are reddish-orange for a few hours before turning black.[2]

Where it lives

At least seven Stethorus species live in the U.S. Stethorus punctum is native in the mid-Atlantic and Midwest; S. picipes is the species found in California.[1][2]

US map: public records from 12 states since 1990 (GBIF).

Biology and life cycle

Females lay about 100 to 200 eggs over a one- to two-month life, one to ten per leaf depending on mite numbers.[1][2]

In warm weather it goes from egg to adult in three to four weeks, and there are usually three overlapping generations.[1][2]

Adults overwinter in leaf litter and other sheltered spots around trees and fence rows.[2]

Damage and signs

  • It is strictly a mite predator. Adults can eat 75 to 100 mites a day and large larvae up to 75.[2][1]
  • It needs about two to five active mites per leaf to stay in a planting, and pockets of eight to ten to breed.[2]

Health risk

Its food is limited to spider mites and other plant-feeding mites; the sources describe no effect on people.[2]

Control

Biological control

Leave leaf litter under fruit trees undisturbed from November to late April, because overwintering adults shelter there.[2]

Some miticides and insect growth regulators, including abamectin and fenoxycarb, harmed it in studies.[2]

It isn't sold commercially, so conserving local beetles is the way to use it.[2]

Common questions

What are the tiny black beetles in my mite-infested plants?
Possibly spider mite destroyers. Adults fly well and gather where mites are thick, then lay eggs there.[1]
Are the reddish hairy larvae a problem?
No. Spider mite destroyer larvae turn reddish as they mature and feed on all stages of spider mites.[1][2]
Can I buy spider mite destroyers?
Cornell lists them as not commercially available.[2]

Sources

  1. University of California Statewide IPM Program, “Spider Mite Destroyer (Natural Enemies Gallery).” ipm.ucanr.edu/natural-enemies/spider-mite-destroyer/ (accessed 2026-10-06)
  2. Cornell University College of Agriculture and Life Sciences, “Biological Control: A Guide to Natural Enemies in North America: Stethorus punctum.” biocontrol.entomology.cornell.edu/predators/Stethorus.php (accessed 2026-10-06)
  3. iNaturalist, “Stethorus taxon page (order and family).” www.inaturalist.org/taxa/211369 (accessed 2026-10-06)

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