Hosts or Prey
Greenhouse thrips and certain other thrips
Identification
The presence of T. javae can be recognized by distorted and swollen (parasitized) thrips larvae and black, oblong parasitoid puparium (covering of the pupa). Unlike the active, black adult of greenhouse thrips that has whitish wings, the black parasitoid puparium lack wings and do not move.
Adult T. javae are wasps about 1/32 inch (0.8 mm) long. The abdomen and antennae are pale yellow and the head and thorax are blackish. The eyes are dark red and the wings are clear.
Thripoctenus javae eggs, larvae, and pupae occur hidden inside host thrips. The pale parasitoid eggs are oval and the pale larvae are maggotlike. As a parasitoid larva ages inside the yellow larva of greenhouse thrips it causes the thrips to become somewhat distorted and swollen. When the parasitoid pupates it blackens the covering of the parasitized thrips larva.
Life Cycle
Thripoctenus develops through 4 life stages: egg, larva, pupa, and adult. All individuals are female. During her lifespan an adult wasp lays about 80 eggs, 1 each in first or second instar thrips. The wasp larva feeds inside on the thrips' body contents while developing through 3 or 4 increasingly larger instars. Thripoctenus kills the thrips shortly before it pupates. Thripoctenus javae pupates inside the blackened skin of the dead thrips then emerges as an adult wasp.
Thripoctenus adults have a short lifespan of about 4 days when temperatures are warm. But during this time each female can parasitize about 20 thrips per day.
When temperatures average 73°F T. javae develops from an egg to a reproductive adult in about 25 days. There are multiple generations per year.
Habitat
This parasitoid was deliberately introduced into California in 1986 from New South Wales, Australia. It is common in Australia on greenhouse thrips infesting liquidambar (sweetgum) trees. In California Thripoctenus javae is considered an important parasitoid of greenhouse thrips in coastal avocado groves.
To improve biological control
- Control ants because they attack natural enemies of various pests.
- Grow flowering insectary plants to provide nectar for adult natural enemies.
- Reduce dustiness that disrupts the activities of natural enemies (e.g., irrigate overhead or periodically hose off small plants).
- Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.
For more information see Protecting Natural Enemies and Pollinators and the table of relative toxicities of insecticides and miticides to natural enemies and honey bees for specific crops.
Species
Thripoctenus javae is the only member of its genus reported in California. It parasitizes at least eight thrips species of which three occur in California: Heliothrips haemorrhoidalis, Rhipiphorothrips cruentatus, and Selenothrips rubrocinctus.
Greenhouse thrips in California is also parasitized by a Trichogrammatidae egg parasitoid, Megaphragma mymaripenne. The adult M. mymaripenne is only about 1/100 inch (0.25 mm) long, one of the smallest insects known.
More Information
- Biological Parameters of Thripobius semiluteus Boucek (Hym., Eulophidae), a Larval Endoparasitoid of Heliothrips haemorrhoidalis (Bouche) (Thysan., Thripidae), Journal of Applied Entomology
- Imported Parasitoid of Greenhouse Thrips Established on California Avocado, UC Riverside, California Agriculture
- Universal Chalcidoidea Database, Natural History Museum of London
Scientific classification:
- Phylum: Arthropoda
- Class: Insecta
- Order: Hymenoptera
- Family: Eulophidae
