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How to identify it
- Adults are only 2 to 3 mm (about 1/8 inch) long and yellowish brown, with darker antennae nearly as long as the body. Females hold their antennae bent; males do not.[1]
- The easiest sign is the mealybug it leaves behind: a parasitized mealybug turns brown, swells and becomes a brown to dark brown 'mummy'. When the adult wasp leaves, it chews an exit hole in the mummy.[1][3]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Coccidoxenoides perminutus | Another small wasp that parasitizes mealybugs and is also sold in the United States. Mealybugs it kills become smaller, greenish mummies instead of brown ones.[2] |
Where it lives
It is thought to be native to South America and Africa but has spread around the world. It has been released against mealybugs in the Middle East, Europe, the United States, Pakistan, India and Australia, and it has been used in California vineyards and Florida citrus.[1]
Biology and life cycle
A female lays a single egg inside each mealybug she chooses, preferring large nymphs, and she can tell an already parasitized mealybug from a healthy one. She can lay up to 10 eggs a day and about 51 to 66 in her life.[1]
Once parasitized, a mealybug stops feeding and never lays eggs. The wasp larva goes through four stages and pupates inside the mealybug's body.[1]
At 25 °C (77 °F) it completes a generation in 16 to 18 days; overall the life cycle takes about three to four weeks depending on temperature and mealybug size. Adults live two to three weeks and feed on mealybug honeydew, nectar and pollen.[1]
It does best in warmth, reproducing most at 26 to 30 °C (79 to 86 °F). Females fail to lay eggs below 18 °C (64 °F), and the species is very sensitive to cold and cannot overwinter for long.[1]
It attacks more than 20 kinds of mealybugs. Its preferred hosts are citrus mealybug, vine mealybug, longtailed mealybug and obscure mealybug, and it also attacks passionvine mealybug.[1][2]
Damage and signs
- It does no damage. It is a beneficial insect that helps control mealybugs, which are serious pests of citrus in Florida.[1]
Health risk
The sources describe it only as a tiny parasite of mealybugs; none mentions stings or any risk to people or pets.[1][3]
Control
Prevention
No control is needed. It is a beneficial insect that reduces mealybug numbers, so leave it alone.[1]
Biological control
It can be bought and released against mealybugs in greenhouses, interiorscapes and citrus groves, and UF/IFAS considers it well suited to small nurseries and greenhouses as well as orchards. In India, releases controlled citrus mealybug in two orchards within three to four months.[3][1]
Pesticides
Choose insecticides carefully where it is working. In laboratory tests, dinotefuran killed all adult wasps within a day, and kinoprene applied a day before release killed all of them and cut parasitism; buprofezin, pyriproxyfen, flonicamid and azadirachtin caused little or no adult mortality, though pyriproxyfen reduced parasitism on coleus in one study.[4][5]
Common questions
- What are the brown, swollen mealybugs with holes in them?
- Those are probably mummies left by parasitic wasps such as Leptomastix dactylopii. A parasitized mealybug turns brown and bloated, and the adult wasp chews its way out, leaving a hole.[1][3]
- Will Leptomastix dactylopii work outdoors in winter?
- Not well. Females stop laying eggs below about 18 °C (64 °F), the species cannot overwinter for long, and it reproduces best at 26 to 30 °C (79 to 86 °F).[1]
- Does Leptomastix dactylopii sting people?
- None of the sources mentions any risk to people; they describe it only as a 2 to 3 mm parasite of mealybugs.[1]
Sources
- University of Florida IFAS Extension (EDIS Featured Creatures), “Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae): parasitoid of mealybugs (EENY-807, 2024).” journals.flvc.org/edis/article/view/134441 (accessed 2026-11-09)
- University of Florida IFAS Extension (EDIS), “Passionvine Mealybug, Planococcus minor (Maskell) (Hemiptera: Pseudococcidae) (ENY-920).” journals.flvc.org/edis/article/view/119515 (accessed 2026-11-09)
- University of California Statewide IPM Program, “Pest Notes: Mealybugs (UC ANR Publication 74174).” ipm.ucanr.edu/home-and-landscape/mealybugs/ (accessed 2026-11-09)
- Entomological Society of America (Journal of Economic Entomology), “Effect of insecticides on mealybug destroyer and parasitoid Leptomastix dactylopii, natural enemies of citrus mealybug (Cloyd and Dickinson 2006, Journal of Economic Entomology 99:1596-1604).” doi.org/10.1603/0022-0493-99.5.1596 (accessed 2026-11-09)
- Entomological Society of America (Journal of Economic Entomology), “Effects of insect growth regulators on citrus mealybug parasitoid Leptomastix dactylopii (Rothwangl et al. 2004, Journal of Economic Entomology 97:1239-1244).” doi.org/10.1093/jee/97.4.1239 (accessed 2026-11-09)
- iNaturalist, “Leptomastix dactylopii taxon page (order and family).” www.inaturalist.org/taxa/672693 (accessed 2026-11-09)