Lifecycle of Greenhouse Thrips and Thripobius

Greenhouse thrips lifecycle at 23°C (similar to summer temperatures)
The kidney-shaped, transparent eggs are laid under the surface of the host plant tissue and hatch after about 16 days.

1st larval stage	2nd larval stage	Prepupa	Pupa

A tiny larva hatches from the egg, feeds and grows for 5 days, and then moults into a second larval stage. The second larval stage continues to feed for a further 4-5 days before aggregating with other late second stage larvae and pupae in a sheltered spot to pupate. Both larval stages carry a ball of liquid excrement (faecal droplet) on the tip of their upturned abdomen, which gives their feeding site a characteristic spotty appearance.

The subsequent stages, prepupae and pupae, both have wing buds, and on the pupae the antennae are folded down. They remain as prepupae for as little as 12-24hrs before changing to pupae. Pupae are non-feeding and largely motionless unless disturbed. They stay as pupae for about 4 days before moulting to become adults. Greenhouse thrips are very unusual in that they pupate on the host plant rather than in the soil like most other thrips species.

Greenhouse thrips adult

The adult has cream coloured wings and legs. Freshly emerged adults have light yellow to orange abdomens that harden and turn dark brown/black after 24hrs. The adults are all females and reproduce without males. They start laying eggs after 6-10 days, and lay one egg every one to two days for the next 20-30 days. Most adults will lay 15-25 eggs in a lifetime (about 70 days). The adults feed on the plant tissue and oviposit (lay eggs) under the surface of the leaf or fruit. Adults cause considerably more damage to fruit than larvae.

Thripobius lifecycle at 23°C
The adult Thripobius wasp lays individual eggs into the first and small second stage larvae. The wasp larvae feeds inside the thrips larvae until the prepupae stage of the thrips (about 11 days). It then takes over the entire body of the thrips and forms a black coloured pupae. This stage is completely stationary and the parasitoid is quite protected. After another 11 days the tiny adult wasp emerges from the pupa and begins hunting for thrips larvae to lay eggs in. The adult wasps only live for 3-4 days and most of the eggs (approximately 40-60) are laid on the second day.

The adult Thripobius wasp is only 0.6mm in length, about half the size of the adult thrips.

(See also Greenhouse Thrips Parasite - Rearing Workshops)

If you require more information, please contact:

Karyn Froud, Scientist
HortResearch Mt Albert
120 Mt Albert Road
Private Bag 92 169
AUCKLAND, NZ
Tel: 09 8154200 Fax: 09 8154201
kfroud@hortresearch.co.nz
Mobile: 021 653 215

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